Horizontal and Vertical Distribution of Perfluoroalkyl Acids (PFAAs) in the Water Column of the Atlantic Ocean

2023. Eleni Konstantina Savvidou (et al.). Environmental Science and Technology Letters 10 (5), 418-424

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Perfluoroalkyl acids (PFAAs) are widely distributed in the oceans which are their largest global reservoir, but knowledge is limited about their vertical distribution and fate. This study measured the concentrations of PFAAs (perfluoroalkyl carboxylic acids (PFCAs) with 6 to 11 carbons and perfluoroalkanesulfonic acids (PFSAs) with 6 and 8 carbons) in the surface and deep ocean. Seawater depth profiles from the surface to a 5000 m depth at 28 sampling stations were collected in the Atlantic Ocean from similar to 50 degrees N to similar to 50 degrees S. The results demonstrated PFAA input from the Mediterranean Sea and the English Channel. Elevated PFAA concentrations were observed at the eastern edge of the Northern Atlantic Subtropical Gyre, suggesting that persistent contaminants may accumulate in ocean gyres. The median sigma PFAA surface concentration in the Northern Hemisphere (n = 17) was 105 pg L-1, while for the Southern Hemisphere (n = 11) it was 28 pg L-1. Generally, PFAA concentrations decreased with increasing distance to the coast and increasing depth. The C6-C9 PFCAs and C6 and C8 PFSAs dominated in surface waters, while longer-chain PFAAs (C10-C11 PFCAs) peaked at intermediate depths (500-1500 m). This profile may be explained by stronger sedimentation of longer-chain PFAAs, as they sorb more strongly to particulate organic matter.

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Lithium-ion battery recycling: a source of per- and polyfluoroalkyl substances (PFAS) to the environment?

2023. Amanda Rensmo (et al.). Environmental Science

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Recycling of lithium-ion batteries (LIBs) is a rapidly growing industry, which is vital to address the increasing demand for metals, and to achieve a sustainable circular economy. Relatively little information is known about the environmental risks posed by LIB recycling, in particular with regards to the emission of persistent (in)organic fluorinated chemicals. Here we present an overview on the use of fluorinated substances – in particular per- and polyfluoroalkyl substances (PFAS) – in state-of-the-art LIBs, along with recycling conditions which may lead to their formation and/or release to the environment. Both organic and inorganic fluorinated substances are widely reported in LIB components, including the electrodes and binder, electrolyte (and additives), and separator. Among the most common substances are LiPF₆ (an electrolyte salt), and the polymeric PFAS polyvinylidene fluoride (used as an electrode binder and a separator). Currently the most common LIB recycling process involves pyrometallurgy, which operates at high temperatures (up to 1600 °C), sufficient for PFAS mineralization. However, hydrometallurgy, an increasingly popular alternative recycling approach, operates under milder temperatures (<600 °C), which could favor incomplete degradation and/or formation and release of persistent fluorinated substances. This is supported by the wide range of fluorinated substances detected in bench-scale LIB recycling experiments. Overall, this review highlights the need to further investigate emissions of fluorinated substances during LIB recycling and suggests that substitution of PFAS-based materials (i.e. during manufacturing), or alternatively post-treatments and/or changes in process conditions may be required to avoid formation and emission of persistent fluorinated substances.

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Managing PMT/vPvM substances in consumer products through the concepts of essential-use and functional substitution: a case-study for cosmetics

2023. Joanke van Dijk (et al.). Environmental Science 25 (6), 1067-1081

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Measures are needed to protect water sources from substances that are mobile, persistent and toxic (PMT) or very persistent and very mobile (vPvM). PMT/vPvM substances are used in a diverse range of applications, including consumer products. The combined application of the essential-use and functional substitution concepts has been proposed to phase out substances of concern and support the transition to safer and more sustainable chemicals, a key goal of the European Commission’s Chemicals Strategy for Sustainability. Here, we first identified the market share of PMT/vPvM containing cosmetic products. We found that 6.4% of cosmetic products available on the European market contain PMT or vPvM substances. PMT/vPvM substances were most often found in hair care products. Based on their high occurrence, the substances Allura red (CAS 25956-17-6), benzophenone-4 (CAS 4065-45-6) and climbazole (CAS 38083-17-9) were selected as case-studies for assessment of their functionality, availability of safer alternatives and essentiality. Following the functional substitution framework, we found that the technical function of Allura red was not necessary for the performance of some cosmetic products, making the use non-essential. For other applications of Allura red, as well as all applications of benzophenone-4 and climbazole, the technical function of the chemical was considered necessary for the performance. Via the alternative’s assessment procedure, which used experimental and in silico data and three different multicriteria decision analysis (MCDA) strategies, safer alternatives were identified for all case-study chemicals. All assessed uses of PMT/vPvM substances were thus deemed non-essential and should consequently be phased out.

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The essential-use concept: a valuable tool to guide decision-making on applications for authorisation under REACH?

2023. Romain Figuière (et al.). Environmental Sciences Europe 35

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Background In 2020, the European Commission published the Chemical Strategy for Sustainability (CSS) in which it aims to increase the level of protection for human health and the environment from hazardous chemicals. Part of the implementation of the CSS will involve a reform of the REACH authorisation and restriction processes. One option for the reform of the authorisation process is to implement the essential-use concept as a tool to guide decision-making on applications for authorisation to make the process more efficient and to align it with societal needs. The purpose of this study is to investigate whether changes in the legal text that defines the authorisation process, and of the amount and type of information that applicants should provide in an application for authorisation, are needed to enable an implementation of the essential-use concept.

Results The results suggest that no fundamental changes in the regulatory requirements are needed and that applicants should already provide sufficient and relevant information to the authorities to determine if the use(s) applied for is (are) essential.

Conclusions Although the REACH authorisation already provides a legal and practical basis for an implementation of the essential-use concept, the feasibility of the essentiality assessment and its potential to make the decision-making on applications more efficient are highly dependent on the quality of the information provided and the clearness of decision criteria. However, if an applicant successfully demonstrates that the risk related to the use(s) applied for is adequately controlled, it could not be legally justified for the European Commission to refuse an authorisation by arguing that the use(s) applied for is (are) non-essential.

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ACS Environmental Au─How to Improve the Reach of Your Open Access Research

2022. Antonia Praetorius, Ian T. Cousins. ACS Environmental Au 2 (5), 373-375

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This Editorial provides suggestions for how authors can boost the visibility and reach of their research. If readers of this Editorial want more detailed guidance, we suggest that they read Rebecca Fuocco’s excellent Career Column in Nature1 and the supporting materials, and ACS Au Editor-in-Chief Shelley Minteer’s recent Editorial on Tips for Improving the Visibility of Research Publications.2 ACS Environmental Au continues to attract top-class contributions on a diversity of topics within the environmental sciences. We were especially delighted to have an ACS Editors’ Choice article in this issue and look forward to having more of these in future issues. As authors, we understand the value of giving your work that extra promotional boost, and as Editors of ACS Environmental Au, we are pleased to support our authors in disseminating their work.

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An Outdoor Aging Study to Investigate the Release of Per- And Polyfluoroalkyl Substances (PFAS) from Functional Textiles

2022. Steffen Schellenberger (et al.). Environmental Science and Technology 56 (6), 3471-3479

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The emission of per- and polyfluoroalkyl substances (PFAS) from functional textiles was investigated via an outdoor weathering experiment in Sydney, Australia. Polyamide (PA) textile fabrics treated with different water-repellent, side-chain fluorinated polymers (SFPs) were exposed on a rooftop to multiple natural stressors, including direct sunlight, precipitation, wind, and heat for 6-months. After weathering, additional stress was applied to the fabrics through abrasion and washing. Textile characterization using a multiplatform analytical approach revealed loss of both PFAS-containing textile fragments (e.g., microfibers) as well as formation and loss of low molecular weight PFAS, both of which occurred throughout weathering. These changes were accompanied by a loss of color and water repellency of the textile. The potential formation of perfluoroalkyl acids (PFAAs) from mobile residuals was quantified by oxidative conversion of extracts from unweathered textiles. Each SFP-textile finish emitted a distinct PFAA pattern following weathering, and in some cases the concentrations exceeded regulatory limits for textiles. In addition to transformation of residual low molecular weight PFAA-precursors, release of polymeric PFAS from degradation and loss of textile fibers/particles contributed to overall PFAS emissions during weathering.

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Combined Application of the Essential-Use and Functional Substitution Concepts: Accelerating Safer Alternatives

2022. Monika A. Roy (et al.). Environmental Science and Technology 56 (14), 9842-9846

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Combined Use of Total Fluorine and Oxidative Fingerprinting for Quantitative Determination of Side-Chain Fluorinated Polymers in Textiles

2022. Ioannis Liagkouridis (et al.). Environmental Science and Technology Letters 9 (1), 30-36

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Given their extensive production volumes and potential to form persistent perfluoroalkyl acids (PFAAs), there is concern surrounding the ongoing use of side-chain fluorinated polymers (SFPs) in consumer products. Targeted SFP quantification relies on matrix-assisted laser desorption ionization time-of-flight mass spectrometry, which can suffer from poor accuracy and high detection limits. Alternatively, total fluorine (TF)-based methods may be used, but these approaches report concentrations on a “fluorine equivalent” basis (e.g., fluorine per square meter in the case of textiles) and are incapable of elucidating structure or chain length. Here a new method for comprehensive characterization of SFPs is presented, which makes use of the total oxidizable precursor assay for fingerprint-based structural elucidation and combustion ion chromatography for TF quantification. When used in parallel, quantitative determination of SFPs (in units of mass of C_nF_2n+1 per square meter of textile) is achieved. Expressing SFP concentrations in terms of the mass of the side chain (as opposed to fluorine equivalents) facilitates estimation of both the structure and quantity of PFAA degradation products. As a proof of principle, the method was applied to six unknown SFP-coated medical textiles from Sweden. Four products contained C6-fluorotelomer-based SFPs (concentration range of 36–188 mg of C₆F₁₃/m²), one contained a C4-sulfonamide-based SFP (718 mg of C₄F₉/m²), and one contained a C8-fluorotelomer-based SFP (249 mg of C₈F₁₇/m²).

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Emerging Contaminants: Fluorinated Alternatives to Existing PFAS

2022. Ting Ruan (et al.). Environmental Science and Technology 56 (10), 6001-6003

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European scale assessment of the potential of ozonation and activated carbon treatment to reduce micropollutant emissions with wastewater

2022. Alberto Pistocchi (et al.). Science of the Total Environment 848

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Micropollutants (MPs) in wastewater pose a growing concern for their potential adverse effects on the receiving aquatic environment, and some countries have started requiring that wastewater treatment plants remove them to a certain extent. Broad spectrum advanced treatment processes, such as ozonation, activated carbon or their combination, are expected to yield a significant reduction in the toxicity of effluents. Here we quantify the reduction of effluent toxicity potentially achieved by implementing these advanced treatment solutions in a selection of European wastewater treatment plants. To this end, we refer to a list of “total pollution proxy substances” (TPPS) composed of 1337 chemicals commonly found in wastewater effluents according to a compilation of datasets of measured concentrations. We consider these substances as an approximation of the “chemical universe” impinging on the European wastewater system. We evaluate the fate of the TPPS in conventional and advanced treatment plants using a compilation of experimental physicochemical properties that describe their sorption, volatilization and biodegradation during activated sludge treatment, as well as known removal efficiency in ozonation and activated carbon treatment, while filling the gaps through in silico prediction models.

We estimate that the discharge of micropollutants with wastewater effluents in the European Union has a cumulative MP toxicity to the environment equal to the discharge of untreated wastewater of ca. 160 million population equivalents (PE), i.e. about 30 % of the generated wastewater in the EU. If all plants above a capacity of 100,000 PE were equipped with advanced treatment, we show that this load would be reduced to about 95 million PE. In addition, implementing advanced treatment in wastewater plants above 10,000 PE discharging to water bodies with an average dilution ratio smaller than 10 would yield a widespread improvement in terms of exposure of freshwater ecosystems to micropollutants, almost halving the part of the stream network exposed to the highest toxic risks.

Our analysis provides background for a cost-effectiveness appraisal of advanced treatment “at the end of the pipe”, which could lead to optimized interventions. This should not be regarded as a stand-alone solution, but as a complement to policies for the control of emissions at the source for the most problematic MPs.

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Grouping of PFAS for human health risk assessment: Findings from an independent panel of experts

2022. J. K. Anderson (et al.). Regulatory toxicology and pharmacology 134

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An expert panel was convened to provide insight and guidance on per-and polyfluoroalkyl substances (PFAS) grouping for the purposes of protecting human health from drinking water exposures, and how risks to PFAS mixtures should be assessed. These questions were addressed through multiple rounds of blind, independent responses to charge questions, and review and comments on co-panelists responses. The experts agreed that the lack of consistent interpretations of human health risk for well-studied PFAS and the lack of information for the vast majority of PFAS present significant challenges for any mixtures risk assessment approach. Most experts agreed that all PFAS should not be grouped together, persistence alone is not sufficient for grouping PFAS for the purposes of assessing human health risk, and that the definition of appropriate subgroups can only be defined on a case-by-case manner. Most panelists agreed that it is inappropriate to assume equal toxicity/potency across the diverse class of PFAS. A tiered approach combining multiple lines of evidence was presented as a possible viable means for addressing PFAS that lack analytical and/or toxicological studies. Most PFAS risk assessments will need to employ assumptions that are more likely to overestimate risk than to underestimate risk, given the choice of assumptions regarding dose-response model, uncertainty factors, and exposure information.

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Information Requirements under the Essential-Use Concept: PFA Case Studies br

2022. Juliane Glüge (et al.). Environmental Science and Technology 56 (10), 6232-6242

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Per- and polyfluoroalkyl substances (PFAS) are a class of substances for which there are widespread concerns about their extreme persistence in combination with toxic effects. It has been argued that PFAS should only be employed in those uses that are necessary for health or safety or are critical for the functioning of society and where no alternatives are available (“essential-use concept”). Implementing the essential-use concept requires a sufficient understanding of the current uses of PFAS and of the availability, suitability, and hazardous properties of alternatives. To illustrate the information requirements under the essential-use concept, we investigate seven different PFAS uses, three in consumer products and four industrial applications. We investigate how much information is available on the types and functions of PFAS in these uses, how much information is available on alternatives, their performance and hazardous properties and, finally, whether this information is sufficient as a basis for deciding on the essentiality of a PFAS use. The results show (i) the uses of PFAS are highly diverse and information on alternatives is often limited or lacking; (ii) PFAS in consumer products often are relatively easy to replace; (iii) PFAS uses in industrial processes can be highly complex and a thorough evaluation of the technical function of each PFAS and of the suitability of alternatives is needed; (iv) more coordination among PFAS manufacturers, manufacturers of alternatives to PFAS, users of these materials, government authorities, and other stakeholders is needed to make the process of phasing out PFAS more transparent and coherent.

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Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS)

2022. Ian Cousins (et al.). Environmental Science and Technology 56 (16), 11172-11179

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It is hypothesized that environmental contamination by per- and polyfluoroalkyl substances (PFAS) defines a separate planetary boundary and that this boundary has been exceeded. This hypothesis is tested by comparing the levels of four selected perfluoroalkyl acids (PFAAs) (i.e., perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)) in various global environmental media (i.e., rainwater, soils, and surface waters) with recently proposed guideline levels. On the basis of the four PFAAs considered, it is concluded that (1) levels of PFOA and PFOS in rainwater often greatly exceed US Environmental Protection Agency (EPA) Lifetime Drinking Water Health Advisory levels and the sum of the aforementioned four PFAAs (Σ4 PFAS) in rainwater is often above Danish drinking water limit values also based on Σ4 PFAS; (2) levels of PFOS in rainwater are often above Environmental Quality Standard for Inland European Union Surface Water; and (3) atmospheric deposition also leads to global soils being ubiquitously contaminated and to be often above proposed Dutch guideline values. It is, therefore, concluded that the global spread of these four PFAAs in the atmosphere has led to the planetary boundary for chemical pollution being exceeded. Levels of PFAAs in atmospheric deposition are especially poorly reversible because of the high persistence of PFAAs and their ability to continuously cycle in the hydrosphere, including on sea spray aerosols emitted from the oceans. Because of the poor reversibility of environmental exposure to PFAS and their associated effects, it is vitally important that PFAS uses and emissions are rapidly restricted.

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Probing the impact of a phytoplankton bloom on the chemistry of nascent sea spray aerosol using high-resolution mass spectrometry

2022. Nikola Radoman (et al.). Environmental Science 2 (5), 1152-1169

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Sea spray aerosol is the largest natural source of aerosol to Earth's atmosphere with significant impacts on climate. Despite this, estimates of the impact of sea spray aerosol on Earth's radiation budget are highly uncertain due to an overall lack of understanding of the physical and chemical factors controlling its composition. Critically, results from studies probing the importance of oceanic biological activity on the amount and type of organic matter present in nascent sea spray aerosol have been ambiguous. Some field studies have shown a relationship between the organic fraction of sea spray aerosol and oceanic primary productivity while others have reported no such relationships. Given this, we have probed the composition of seawater and nascent sea spray aerosol during a phytoplankton bloom in the North Atlantic using a novel liquid chromatography-mass spectrometry method. We observed that the composition of dissolved organic matter present in seawater changed as the phytoplankton bloom progressed over an 18 day period. Further, we observed changes to both the chemical composition of the organic matter present in seawater and the chemical composition of the organic matter present in the sea spray aerosol despite the organic matter mass fraction of the aerosol remaining unchanged. More specifically, we observed that the nascent sea spray aerosol became progressively more enriched in surface-active organic substances as the bloom progressed and that the sea spray aerosol had a distinct organic matter composition compared to the seawater. Thus, our work provides additional insight into the biological dependence of nascent sea spray aerosol composition.

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Sea Spray Aerosol (SSA) as a Source of Perfluoroalkyl Acids (PFAAs) to the Atmosphere: Field Evidence from Long-Term Air Monitoring

2022. Bo Sha (et al.). Environmental Science and Technology 56 (1), 228-238

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The effective enrichment of perfluoroalkyl acids (PFAAs) in sea spray aerosols (SSA) demonstrated in previous laboratory studies suggests that SSA is a potential source of PFAAs to the atmosphere. In order to investigate the influence of SSA on atmospheric PFAAs in the field, 48 h aerosol samples were collected regularly between 2018 and 2020 at two Norwegian coastal locations, Andoya and Birkenes. Significant correlations (p < 0.05) between the SSA tracer ion, Na+, and PFAA concentrations were observed in the samples from both locations, with Pearson's correlation coefficients (r) between 0.4-0.8. Such significant correlations indicate SSA to be an important source of atmospheric PFAAs to coastal areas. The correlations in the samples from Andoya were observed for more PFAA species and were generally stronger than in the samples from Birkenes, which is located further away from the coast and closer to urban areas than Andøya. Factors such as the origin of the SSA, the distance of the sampling site to open water, and the presence of other PFAA sources (e.g., volatile precursor compounds) can have influence on the contribution of SSA to PFAA in air at the sampling sites and therefore affect the observed correlations between PFAAs and Na+.

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Addressing Urgent Questions for PFAS in the 21st Century

2021. Carla Ng (et al.). Environmental Science and Technology 55 (19), 12755-12765

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Despite decades of research on per- and polyfluoroalkyl substances (PFAS), fundamental obstacles remain to addressing worldwide contamination by these chemicals and their associated impacts on environmental quality and health. Here, we propose six urgent questions relevant to science, technology, and policy that must be tackled to address the “PFAS problem”: (1) What are the global production volumes of PFAS, and where are PFAS used? (2) Where are the unknown PFAS hotspots in the environment? (3) How can we make measuring PFAS globally accessible? (4) How can we safely manage PFAS-containing waste? (5) How do we understand and describe the health effects of PFAS exposure? (6) Who pays the costs of PFAS contamination? The importance of each question and barriers to progress are briefly described, and several potential paths forward are proposed. Given the diversity of PFAS and their uses, the extreme persistence of most PFAS, the striking ongoing lack of fundamental information, and the inequity of the health and environmental impacts from PFAS contamination, there is a need for scientific and regulatory communities to work together, with cooperation from PFAS-related industries, to fill in critical data gaps and protect human health and the environment.

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Estimating Environmental Hazard and Risks from Exposure to Per- and Polyfluoroalkyl Substances (PFASs): Outcome of a SETAC Focused Topic Meeting

2021. Mark S. Johnson (et al.). Environmental Toxicology and Chemistry 40 (3), 543-549

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Per- and polyfluoroalkyl substances (PFAS) are a group of highly fluorinated synthetic chemicals that were originally developed for uses as surfactants and surface protectors. Increasingly, specific substances of this class are being found in environmental media (e.g., surface water, soils, sediments, food sources), and concerns regarding exposure to humans and environmental receptors have been described by the public, legislators, and the general population. Data suggest that some PFAS (such as certain of the long-chain ones) bioaccumulate and have long biological half-lives, particularly in humans. Toxicity data in various organisms are variable as are their toxicokinetics. A Society of Environmental Toxicology and Chemistry (SETAC) Focused Topic Meeting and workshop entitled Environmental Risk Assessment of PFAS convened during 12 to 15 August, 2019 in Durham, North Carolina (USA) and brought together experts from around the globe to highlight recent advances in research pertinent to evaluating environmental and human health risks from exposures. The objectives of the Focused Topic Meeting and workshop were: 1) to review new and emerging information on PFAS chemical classification and grouping, environmental chemistry, detection technology, fate and transport, exposure potential, human health toxicity, and ecological toxicity; and 2) to harness the expertise of attendees to discuss and formulate a roadmap to prioritize the study of specific PFAS with the goal of developing a risk assessment approach that considers mechanistic (including computational) data for extrapolating exposure and data across different species/scenarios and compounds within environmental exposure pathways. We present the key issues that were discussed.

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Finding essentiality feasible: common questions and misinterpretations concerning the "essential-use" concept

2021. Ian T. Cousins (et al.). Environmental Science 23 (8), 1079-1087

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The essential-use concept is a tool that can guide the phase-out of per- and polyfluoroalkyl substances (PFAS) and potentially other substances of concern. This concept is a novel approach to chemicals management that determines whether using substances of concern, such as PFAS, is truly essential for a given functionality. To assess the essentiality of a particular use case, three considerations need to be addressed: (1) the function (chemical, end use and service) that the chemical provides in the use case, (2) whether the function is necessary for health and safety and critical for the functioning of society and (3) if the function is necessary, whether there are viable alternatives for the chemical for this particular use. A few illustrative examples of the three-step process are provided for use cases of PFAS. The essential-use concept takes chemicals management away from a substance-by-substance approach to a group approach. For PFAS and other substances of concern, it offers a more rapid pathway toward effective management or phase-out. Parts of the concept of essential use have already been widely applied in global treaties and international regulations and it has also been recently used by product manufacturers and retailers to phase out substances of concern from supply chains. Herein some of the common questions and misinterpretations regarding the practical application of the essential-use concept are reviewed, and answers and further clarifications are provided.

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Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols

2021. Bo Sha (et al.). Environmental Science and Technology 55 (14), 9489-9497

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Perfluoroalkyl acids (PFAAs) are persistent organic substances that have been widely detected in the global oceans. Previous laboratory experiments have demonstrated effective enrichment of PFAAs in nascent sea spray aerosols (SSA), suggesting that SSA are an important source of PFAAs to the atmosphere. In the present study, the effects of the water concentration of PFAAs on their size-resolved enrichment in SSA were examined using a sea spray simulation chamber. Aerosolization of the target compounds in almost all sizes of SSA revealed a strong linear relationship with their water concentrations (p < 0.05, r(2) > 0.9). The enrichment factors (EF) of the target compounds showed no correlation with their concentrations in the chamber water, despite the concentrations varying by a factor of 500 (similar to 0.3 to similar to 150 ng L-1). The particle surface-area-to-volume ratio appeared to be a key predictor of the enrichment of perfluoroalkyl carboxylic acids (PFCAs) with >= 7 perfluorinated carbons and perfluoroalkanesulfonic acids (PFSAs) with >= 6 perfluorinated carbons in supermicron particles (p < 0.05, r(2) > 0.8), but not in submicron particles. The different enrichment behaviors of PFAAs in submicron and supermicron particles might be a result of the different production mechanisms of film droplets and jet droplets. The results suggest that the variability in seawater concentrations of PFAAs has little influence on EFs and that modeling studies designed to quantify the source of PFAAs via SSA emissions do not need to consider this factor.

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Sorption of PFOS in 114 Well-Characterized Tropical and Temperate Soils: Application of Multivariate and Artificial Neural Network Analyses

2021. Anthony C. Umeh (et al.). Environmental Science and Technology 55 (3), 1779-1789

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The influence of soil properties on PFOS sorption are not fully understood, particularly for variable charge soils. PFOS batch sorption isotherms were conducted for 114 temperate and tropical soils from Australia and Fiji, that were well-characterized for their soil properties, including total organic carbon (TOC), anion exchange capacity, and surface charge. In most soils, PFOS sorption isotherms were nonlinear. PFOS sorption distribution coefficients (K_d) ranged from 5 to 229 mL/g (median: 28 mL/g), with 63% of the Fijian soils and 35% of the Australian soils showing K_d values that exceeded the observed median K_d. Multiple linear regression showed that TOC, amorphous aluminum and iron oxides contents, anion exchange capacity, pH, and silt content, jointly explained about 53% of the variance in PFOS K_d in soils. Variable charge soils with net positive surface charges, and moderate to elevated TOC content, generally displayed enhanced PFOS sorption than in temperate or tropical soils with TOC as the only sorbent phase, especially at acidic pH ranges. For the first time, two artificial neural networks were developed to predict the measured PFOS K_d (R² = 0.80) in the soils. Overall, both TOC and surface charge characteristics of soils are important for describing PFOS sorption.

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An (Eco)Toxicity Life Cycle Impact Assessment Framework for Per-And Polyfluoroalkyl Substances

2020. Hanna Holmquist (et al.). Environmental Science and Technology 54 (10), 6224-6234

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A framework for characterizing per- and polyfluoroalkyl substances (PFASs) in life cycle impact assessment (LCIA) is proposed. Thousands of PFASs are used worldwide, with special properties imparted by the fluorinated alkyl chain. Our framework makes it possible to characterize a large part of the family of PFASs by introducing transformation fractions that translate emissions of primary emitted PFASs into the highly persistent terminal degradation products: the perfluoroalkyl acids (PFAAs). Using a PFAA-adapted characterization model, human toxicity as well as marine and freshwater aquatic ecotoxicity characterization factors are calculated for three PFAAs, namely perfluorooctanoic acid (PFOA) perfluorohexanoic acid (PFHxA) and perfluorobutanesulfonic acid (PFBS). The model is evaluated to adequately capture long-term fate, where PFAAs are predicted to accumulate in open oceans. The characterization factors of the three PFAAs are ranked among the top 5% for marine ecotoxicity, when compared to 3104 chemicals in the existing USEtox results databases. Uncertainty analysis indicates potential for equally high ranks for human health impacts. Data availability constitutes an important limitation creating uncertainties. Even so, a life cycle assessment (LCA) case study illustrates practical application of our proposed framework, demonstrating that even low emissions of PFASs can have large effects on LCA results.

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An overview of the uses of per- and polyfluoroalkyl substances (PFAS)

2020. Juliane Glüge (et al.). Environmental Science 22 (12), 2345-2373

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Per- and polyfluoroalkyl substances (PFAS) are of concern because of their high persistence (or that of their degradation products) and their impacts on human and environmental health that are known or can be deduced from some well-studied PFAS. Currently, many different PFAS (on the order of several thousands) are used in a wide range of applications, and there is no comprehensive source of information on the many individual substances and their functions in different applications. Here we provide a broad overview of many use categories where PFAS have been employed and for which function; we also specify which PFAS have been used and discuss the magnitude of the uses. Despite being non-exhaustive, our study clearly demonstrates that PFAS are used in almost all industry branches and many consumer products. In total, more than 200 use categories and subcategories are identified for more than 1400 individual PFAS. In addition to well-known categories such as textile impregnation, fire-fighting foam, and electroplating, the identified use categories also include many categories not described in the scientific literature, including PFAS in ammunition, climbing ropes, guitar strings, artificial turf, and soil remediation. We further discuss several use categories that may be prioritised for finding PFAS-free alternatives. Besides the detailed description of use categories, the present study also provides a list of the identified PFAS per use category, including their exact masses for future analytical studies aiming to identify additional PFAS.

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Are Fluoropolymers Really of Low Concern for Human and Environmental Health and Separate from Other PFAS?

2020. Rainer Lohmann (et al.). Environmental Science and Technology 54 (20), 12820-12828

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Fluoropolymers are a group of polymers within the class of per- and polyfluoroalkyl substances (PFAS). The objective of this analysis is to evaluate the evidence regarding the environmental and human health impacts of fluoropolymers throughout their life cycle(s). Production of some fluoropolymers is intimately linked to the use and emissions of legacy and novel PFAS as polymer processing aids. There are serious concerns regarding the toxicity and adverse effects of fluorinated processing aids on humans and the environment. A variety of other PFAS, including monomers and oligomers, are emitted during the production, processing, use, and end-of-life treatment of fluoropolymers. There are further concerns regarding the safe disposal of fluoropolymers and their associated products and articles at the end of their life cycle. While recycling and reuse of fluoropolymers is performed on some industrial waste, there are only limited options for their recycling from consumer articles. The evidence reviewed in this analysis does not find a scientific rationale for concluding that fluoropolymers are of low concern for environmental and human health. Given fluoropolymers' extreme persistence; emissions associated with their production, use, and disposal; and a high likelihood for human exposure to PFAS, their production and uses should be curtailed except in cases of essential uses.

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Computational material flow analysis for thousands of chemicals of emerging concern in European waters

2020. Jos van Gils (et al.). Journal of Hazardous Materials 397

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Knowledge of exposure to a wide range of chemicals, and the spatio-temporal variability thereof, is urgently needed in the context of protecting and restoring aquatic ecosystems. This paper discusses a computational material flow analysis to predict the occurrence of thousands of man-made organic chemicals on a European scale, based on a novel temporally and spatially resolved modelling framework. The goal was to increase understanding of pressures by emerging chemicals and to complement surface water monitoring data. The ambition was to provide a first step towards a real-life mixture exposure situation accounting for as many chemicals as possible. Comparison of simulated concentrations and chemical monitoring data for 226 substance/basin combinations showed that the simulated concentrations were accurate on average. For 65% and 90% of substance/basin combinations the error was within one and two orders of magnitude respectively. An analysis of the relative importance of uncertainties revealed that inaccuracies in use volume or use type information contributed most to the error for individual substances. To resolve this, we suggest better registration of use types of industrial chemicals, investigation of presence/absence of industrial chemicals in wastewater and runoff samples and more scientific information exchange.

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Environment occurrence of perfluoroalkyl acids and associated human health risks near a major fluorochemical manufacturing park in southwest of China

2020. Shuhong Fang (et al.). Journal of Hazardous Materials 396

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Despite China being the largest global manufacturer of perfluoroalkyl acids (PFAAs), few studies have been carried out on the environmental occurrence and associated human health risks of PFAAs emitted from manufacturing sites in China. Here, river water, tap water, soil and leaf samples were collected around a major fluorochemical manufacturing park (FMP) in the southwest of China in 2019. High EPFAA concentrations (sum of 12 PFAAs) of 3817 ng/L, 3254 ng/L, 322 - 476 ng/g dw and 23401-33749 ng/g dw were measured near the FMP in river water, tap water, soil and leaves, respectively, indicating that the FMP is a point source of PFAAs. PFOA was the predominant PFAA in all samples (58.5-98.6 %) indicating the production or use of PFOA at the FMP. PFOA concentrations in most tap water samples (> 300 ng/L in 31 of 38 samples) exceeded the U.S. EPA health advisory. Proportions of branched PFOA isomers in all samples were in 5.9-47.4 %, suggesting the production or use of PFOA manufactured by electrochemical fluorination at the FMP. It is recommended to focus more attention on branched PFOA isomers in the future because otherwise health risks may be underestimated due to their relatively high proportions in China.

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Levels of per- and polyfluoroalkyl substances (PFAS) in ski wax products on the market in 2019 indicate no changes in formulation

2020. Shuhong Fang, Merle M. Plassmann, Ian T. Cousins. Environmental Science 22 (11), 2142-2146

Artikel

In the summer of 2019, eleven of the best-selling fluorinated ski wax products were purchased from one of Norway's largest sports stores and soon after analysed for a suite of 26 per- and polyfluoroalkyl substances (PFAS). The waxes were shown to contain a wide range of perfluoroalkyl acids, including perfluoroalkyl carboxylic acids with up to 25 carbons. Of particular concern was the finding that perfluorooctanoic acid (PFOA) levels in nine of the eleven ski lubrication products analysed were above the EU limit values of 25 ng g(-1), which came into force on 4(th) July 2020. The ski wax with the highest PFOA levels had a concentration that was 1215 times higher than the EU restrictions. Although some of the ski wax manufacturers have indicated that they have switched to formulations that contain chemistries based on shorter perfluoroalkyl chains, the analytical results show that this is not the case.

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Per- and poly-fluoroalkyl substances (PFAS): Current status and research needs

2020. R. Naidu (et al.). Environmental Technology & Innovation 19

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An expert workshop focusing on per- and poly-fluoroalkyl substances (PFAS) was held in Adelaide, South Australia, Australia in September 2019 following the 8th International Contaminated Site Remediation Conference — CleanUp 2019. The workshop was organised by the Cooperative Research Centre for Contamination and Remediation of the Environment (CRC CARE) and was chaired by Professor Ravi Naidu, CEO and Managing Director of CRC CARE and Director of the Global Centre for Environmental Remediation at the University of Newcastle, NSW. The purpose of the workshop, which was attended by more than 50 experts in the field of contaminated land assessment and management, was to discuss the current state of play and research needs relating to PFAS contaminated sites. This paper provides a summary of the discussions and conclusions and lists actions and needs that the expert group identified as critical for pursuing successful PFAS management and remedy approaches.

This paper is intended to capture the shared information, comments, and current thinking related to PFAS challenges and research needs as identified by the group of expert participants; the write up is not intended to be a complete dissertation on the science and work that has been carried out. With a fast-evolving subject and increased government and public attention on PFAS presence in the environment, the group was convened with the objective of providing value in contributing to solutions to the PFAS challenges that are faced both in Australia and internationally. The text contained herein provides references to observations and methods that the experts drew on in their discussions and in support of their commentary; documentation of the original references was not provided, and the reader should consult the scientific literature if further information and confirmation of observations is required. Following a brief on the background to PFAS challenges, the paper focusses on research gaps identified by experts with focus on Australian soils and groundwater including climatic patterns, an overview of PFAS research in Australia with emphasis on:

Regulatory
Analytical considerations
Ecological and Human Health Risks
Fate and Transport
Remediation and Risk Management.

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Role of the air-water interface in removing perfluoroalkyl acids from drinking water by activated carbon treatment

2020. Pingping Meng (et al.). Journal of Hazardous Materials 386

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Contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) is a worldwide problem. In this study, we for the first time revealed the role of the air-water interface in enhancing the removal of long-chain perfluoroalkyl carboxylic (PFCAs; CnF2n+1COOH, n >= 7) and perfluoroalkane sulfonic (PFSAs; CnF2n+1SO3H, n >= 6) acids, collectively termed as perfluoroalkyl acids (PFAAs), through combined aeration and adsorption on two kinds of activated carbon (AC). Aeration was shown to enhance the removal of long-chain PFAAs through adsorption at the air-water interface and subsequent adsorption of PFAA-enriched air bubbles to the AC. The removal of selected long-chain PFAAs was increased by 50-115 % with the assistance of aeration, depending on the perfluoroalkyl chain length. Aeration is more effective in enhancing long-chain PFAA removal as air-water interface adsorption increases with PFAA chain length due to higher surface activity. After removing adsorbed air bubbles by centrifugation, up to 80 % of the long-chain PFAAs were able to desorb from the sorbent, confirming the contribution of the air-water interface to the adsorption of PFAAs on AC. Aeration during AC treatment of water could enhance the removal of long-chain PFAAs, and improve the performance of AC during water treatment.

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Strategies for grouping per- and polyfluoroalkyl substances (PFAS) to protect human and environmental health

2020. Ian T. Cousins (et al.). Environmental Science 22 (7), 1444-1460

Artikel

Grouping strategies are needed for per- and polyfluoroalkyl substances (PFAS), in part, because it would be time and resource intensive to test and evaluate the more than 4700 PFAS on the global market on a chemical-by-chemical basis. In this paper we review various grouping strategies that could be used to inform actions on these chemicals and outline the motivations, advantages and disadvantages for each. Grouping strategies are subdivided into (1) those based on the intrinsic properties of the PFAS (e.g.persistence, bioaccumulation potential, toxicity, mobility, molecular size) and (2) those that inform risk assessment through estimation of cumulative exposure and/or effects. The most precautionary grouping approach of those reviewed within this article suggests phasing out PFAS based on their high persistence alone (the so-called P-sufficient approach). The least precautionary grouping approach reviewed advocates only grouping PFAS for risk assessment that have the same toxicological effects, modes and mechanisms of action, and elimination kinetics, which would need to be well documented across different PFAS. It is recognised that, given jurisdictional differences in chemical assessment philosophies and methodologies, no one strategy will be generally acceptable. The guiding question we apply to the reviewed grouping strategies is: grouping for what purpose? The motivation behind the grouping (e.g.determining use in productsvs.setting guideline levels for contaminated environments) may lead to different grouping decisions. This assessment provides the necessary context for grouping strategies such that they can be adopted as they are, or built on further, to protect human and environmental health from potential PFAS-related effects.

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The high persistence of PFAS is sufficient for their management as a chemical class

2020. Ian T. Cousins (et al.). Environmental Science 22 (12), 2307-2312

Artikel

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic organic substances with diverse structures, properties, uses, bioaccumulation potentials and toxicities. Despite this high diversity, all PFAS are alike in that they contain perfluoroalkyl moieties that are extremely resistant to environmental and metabolic degradation. The vast majority of PFAS are therefore either non-degradable or transform ultimately into stable terminal transformation products (which are still PFAS). Under the European chemicals regulation this classifies PFAS as very persistent substances (vP). We argue that this high persistence is sufficient concern for their management as a chemical class, and for all non-essential uses of PFAS to be phased out. The continual release of highly persistent PFAS will result in increasing concentrations and increasing probabilities of the occurrence of known and unknown effects. Once adverse effects are identified, the exposure and associated effects will not be easily reversible. Reversing PFAS contamination will be technically challenging, energy intensive, and costly for society, as is evident in the efforts to remove PFAS from contaminated land and drinking water sources.

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Children's exposure to perfluoroalkyl acids - a modelling approach

2019. Fabian G. P. Balk (et al.). Environmental Science 21 (11), 1875-1886

Artikel

Adults are mainly exposed to per- and polyfluoroalkyl substances (PFASs) via ingestion of food, inhalation of air and ingestion of dust, whereas for children the exposure to PFASs is largely unknown. This study aimed to reconstruct the serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in children after infancy up to 10.5 years of age and to test if dietary intake is the major exposure pathway for children to PFOA, PFOS and PFHxS after infancy. For this work, a dataset from a Finnish child cohort study was available, which comprised serum concentrations of the studied perfluoroalkyl acids (PFAAs) and PFAS concentration measurements in dust and air samples from the children's bedrooms. The calculated PFAA intakes were used in a pharmacokinetic model to reconstruct the PFAA serum concentrations from 1 to 10.5 years of age. The calculated PFOA and PFOS intakes were close to current regulatory intake thresholds and diet was the major exposure medium for the 10.5 year-olds. The one-compartment PK model reconstructed median PFOA and PFOS serum concentrations well compared to corresponding measured median serum concentrations, while the modelled PFHxS serum concentrations showed a constant underestimation. The results imply that children's exposure to PFOA and PFOS after breastfeeding and with increasing age resembles the exposure of adults. Further, the children in the Finnish cohort experienced a rather constant exposure to PFOA and PFOS between 1 and 10.5 years of age. The PFHxS exposure sources and respective pharmacokinetic parameter estimations need further investigation.

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Exploring open cheminformatics approaches for categorizing per- and polyfluoroalkyl substances (PFASs)

2019. Bo Sha (et al.). Environmental Science 21 (11), 1835-1851

Artikel

Per- and polyfluoroalkyl substances (PFASs) are a large and diverse class of chemicals of great interest due to their wide commercial applicability, as well as increasing public concern regarding their adverse impacts. A common terminology for PFASs was recommended in 2011, including broad categorization and detailed naming for many PFASs with rather simple molecular structures. Recent advancements in chemical analysis have enabled identification of a wide variety of PFASs that are not covered by this common terminology. The resulting inconsistency in categorizing and naming of PFASs is preventing efficient assimilation of reported information. This article explores how a combination of expert knowledge and cheminformatics approaches could help address this challenge in a systematic manner. First, the splitPFAS approach was developed to systematically subdivide PFASs (for eventual categorization) following a CnF2n+1-X-R pattern into their various parts, with a particular focus on 4 PFAS categories where X is CO, SO2, CH2 and CH2CH2. Then, the open, ontology-based ClassyFire approach was tested for potential applicability to categorizing and naming PFASs using five scenarios of original and simplified structures based on the splitPFAS output. This workflow was applied to a set of 770 PFASs from the latest OECD PFAS list. While splitPFAS categorized PFASs as intended, the ClassyFire results were mixed. These results reveal that open cheminformatics approaches have the potential to assist in categorizing PFASs in a consistent manner, while much development is needed for future systematic naming of PFASs. The splitPFAS tool and related code are publicly available, and include options to extend this proof-of-concept to encompass further PFASs in the future.

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Exposure and ecotoxicological risk assessment of mixtures of top prescribed pharmaceuticals in Swedish freshwaters

2019. Claudia Lindim (et al.). Chemosphere 220, 344-352

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Surface water concentrations of 54 pharmaceuticals were predicted for seven major Swedish rivers and the Stockholm City area basins using the STREAM-EU model. These surface water concentrations were used to predict the ecotoxicological impact resulting from the exposure of aquatic organisms to this mixture of 54 pharmaceuticals. STREAM-EU model results indicated that <10 substances were present at median annual water concentrations greater than 10 with highest concentrations occurring mostly in the more densely populated area of the capital city, Stockholm. There was considerable spatial and temporal variability in the model predictions (1-3 orders of magnitude) due to natural variability (e.g. hydrology, temperature), variations in emissions and uncertainty sources. Local mixture ecotoxicological pressures based on acute EC50 data as well as on chronic NOEC data, expressed as multi-substance potentially affected fraction of species (msPAF), were quantified in 114 separate locations in the water bodies. It was estimated that 5% of the exposed aquatic species would experience exposure at or above their acute EC50 concentrations (so-called acute hazardous concentration for 5% of species, or aHC5) at only 7% of the locations analyzed (8 out of 114 locations). For the evaluation based on chronic NOEC concentrations, the chronic HC5 (cHC5) is exceeded at 27% of the locations. The acute mixture toxic pressure was estimated to be predominantly caused by only three substances in all waterbodies: Furosemide, Tramadol and Ibuprofen. A similar evaluation of chronic toxic pressure evaluation logically demonstrates that more substances play a significant role in causing a higher chronic toxic pressure at more sites as compared to the acute toxic pressure evaluation. In addition to the three substances contributing most to acute effects, the chronic effects are predominantly caused by another five substances: paracetamol, diclofenac, ethinylestradiol, erythromycin and ciprofloxacin. This study provides regulatory authorities and companies responsible for water quality valuable information for targeting remediation measures and monitoring on a substance and location basis.

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Global transport of perfluoroalkyl acids via sea spray aerosol

2019. Jana H. Johansson (et al.). Environmental Science 21 (4), 635-649

Artikel

Perfluoroalkyl acids (PFAAs) are persistent organic pollutants found throughout the world's oceans. Previous research suggests that long-range atmospheric transport of these substances may be substantial. However, it remains unclear what the main sources of PFAAs to the atmosphere are. We have used a laboratory sea spray chamber to study water-to-air transfer of 11 PFAAs via sea spray aerosol (SSA). We observed significant enrichment of all PFAAs relative to sodium in the SSA generated. The highest enrichment was observed in aerosols with aerodynamic diameter < 1.6 mm, which had aerosol PFAA concentrations up to similar to 62 000 times higher than the PFAA water concentrations in the chamber. In surface microlayer samples collected from the sea spray chamber, the enrichment of the substances investigated was orders of magnitude smaller than the enrichment observed in the aerosols. In experiments with mixtures of structural isomers, a lower contribution of branched PFAA isomers was observed in the surface microlayer compared to the bulk water. However, no clear trend was observed in the comparison of structural isomers in SSA and bulk water. Using the measured enrichment factors of perfluorooctanoic acid and perfluorooctane sulfonic acid versus sodium we have estimated global annual emissions of these substances to the atmosphere via SSA as well as their global annual deposition to land areas. Our experiments suggest that SSA may currently be an important source of these substances to the atmosphere and, over certain areas, to terrestrial environments.

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Highly fluorinated chemicals in functional textiles can be replaced by re-evaluating liquid repellency and end-user requirements

2019. Steffen Schellenberger (et al.). Journal of Cleaner Production 217, 134-143

Artikel

Ongoing regulation of, and concerns regarding, polyfluoroalkyl substances (also popularly known as highly fluorinated chemicals), has the textile market to search for sustainable alternative chemistries that can provide similar liquid repellency to polyfluoroalkyl substances in performance textiles. This paper aims to inform the potential substitution of fluorochemicals with more environmentally friendly durable water repellents, taking a case-by-case approach and evaluating protection needs for consumer outdoor clothing and protective clothing separately. Recently developed non-fluorinated durable water repellents, some based on green chemistry principles, were evaluated in an in depth assessment for their functionality against fluorinated short-chain alternatives (with hydro- and oleophobic moieties of carbon chain length or six or less). Repellency towards water and non-polar liquids was evaluated with established standard test methods and at measuring the roll-off angle of liquid droplets with a novel sample holder setup. This improved method allows an enhanced mechanistic understanding of the droplets' roll-off processes on woven textiles. The best non-fluorinated alternatives are high water repellency equal to fluorinated side-chain polymers with short fluorinated carbon chains, and should be considered as suitable substitutes for consumer outdoor clothing. These results are supported by a survey of end-use requirements indicating water repellency and durability were the most important purchasing criteria. For polar liquids, with lower surface tensions, the repellency provided by non-fluorinated alternatives was clearly reduced, although they had a moderate repellency towards liquids with intermediate polarity (eg red wine or synthetic blood). Only fluorinated side-chain polymers with "short" fluorinated carbon chains <= 6 carbons were provided to provide sufficient protection to polar liquids with very low surface tension (olive oil or gastric fluid). Since occupational protective clothing (eg medical clothing) often must provide protection against liquid of a wider range of polarities (eg in the case of medical clothing, to bodily fluids and protect the wearer from the transmission of diseases, current non-Fluorinated DWRs do not provide sufficient liquid repellency. This means that innovations in textile technology are still needed to substitute PFASs in some types of occupational protective clothing and other end uses where oil and stain repellency is essential.

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Release of Side-Chain Fluorinated Polymer-Containing Microplastic Fibers from Functional Textiles During Washing and First Estimates of Perfluoroalkyl Acid Emissions

2019. Steffen Schellenberger (et al.). Environmental Science and Technology 53 (24), 14329-14338

Artikel

The quantity and composition of fibers released from functional textiles during accelerated washing were investigated using the GyroWash method. Two fabrics [polyamide (PA) and polyester/cotton (PES/CO)] were selected and coated with perfluorohexane-based side-chain fluorinated polymers. Fibers released during washing ranged from similar to 10 to 500 mu with a similar distribution for the two textile types. The PA-based fabric released considerably more fibers >20 mu m in length compared to the PES/CO-based fabric (>1000/GyroWash for PA vs similar to 200/GyroWash fibers for PES/CO). After one GyroWash (2-15 domestic washes), fibers that contained approximately 240 and 1300 mu g total fluorine per square meter (mu g F/m(2)) were released from the PA and PES/CO fabrics, respectively. Current understanding of the fate of microplastic fibers suggests that a large fraction of these fibers reach the environment either in effluent wastewater or sewage sludge applied to land. In the environment, the fluorinated side chains will be slowly cleaved from the backbone of the side-chain fluorinated polymers coated on the fibers and then transformed into short-chain perfluoroalkyl acids. On the European scale, emissions of up to similar to 0.7 t of fluorotelomer alcohol (6:2 FTOH) per year were estimated for outdoor rain jackets treated with fluorotelomer-based side-chain fluorinated polymers.

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Spatiotemporal distribution and isomer profiles of perfluoroalkyl acids in airborne particulate matter in Chengdu City, China

2019. Shuhong Fang (et al.). Science of the Total Environment 689, 1235-1243

Artikel

Airborne particulate matter (APM) was collected in four seasons at five different areas of the city of Chengdu, China to study the spatial and seasonal contamination pattern of perfluoroalkyl acids (PFAAs). The results showed that Sigma PFAA concentrations in Downtown Chengdu (mean value: 297 +/- 238 pg/m(3)) were higher than concentrations in suburban areas. The highest concentrations of PFAAs occurred during spring (97.5-709 pg/L; arithmetic mean concentration: 297 +/- 191 pg/L) while the lowest concentration occurred during autumn (9.27-105 pg/L; arithmetic mean concentration 41.1 +/- 24.8 pg/L). Perfluorooctanoic acid (PFOA) was the main PFAA quantified during winter, summer and autumn, and perfluorononanoic acid (PFNA) was the predominant PFAA in spring. Relative humidity (RH) and average daily precipitation (PRE) showed significant negative correlations with PFAA concentrations in winter and summer, suggesting that they played an important role in controlling PFAA concentrations in APM. The linear structural isomer of PFOA (n-PFOA) was the most abundant isomer in APM in Chengdu, with the average proportion of 85.6% +/- 6.13%, higher than the proportion in ECF PFOA commercial products (74.3-77.6%). However, the consistent fingerprint of branched PFOA in the APM implies that ECF PFOA makes a significant contribution to the PFOA in APM. PEELS in the APM collected throughout the year had a mean proportion of 54.0 +/- 8.81% of n-PFOS. This proportion of n-PFOS is lower than commercial ECF products (62.9-78.2%), suggesting an additional proportion of branched PFOS isomers in APM in Chengdu.

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Strengthen the European collaborative environmental research to meet European policy goals for achieving a sustainable, non-toxic environment

2019. Werner Brack (et al.). Environmental Sciences Europe 31 (1)

Artikel

To meet the United Nations (UN) sustainable development goals and the European Union (EU) strategy for a non-toxic environment, water resources and ecosystems management require cost-efficient solutions for prevailing complex contamination and multiple stressor exposures. For the protection of water resources under global change conditions, specific research needs for prediction, monitoring, assessment and abatement of multiple stressors emerge with respect to maintaining human needs, biodiversity, and ecosystem services. Collaborative European research seems an ideal instrument to mobilize the required transdisciplinary scientific support and tackle the large-scale dimension and develop options required for implementation of European policies. Calls for research on minimizing society's chemical footprints in the water-food-energy-security nexus are required. European research should be complemented with targeted national scientific funding to address specific transformation pathways and support the evaluation, demonstration and implementation of novel approaches on regional scales. The foreseeable pressure developments due to demographic, economic and climate changes require solution-oriented thinking, focusing on the assessment of sustainable abatement options and transformation pathways rather than on status evaluation. Stakeholder involvement is a key success factor in collaborative projects as it allows capturing added value, to address other levels of complexity, and find smarter solutions by synthesizing scientific evidence, integrating governance issues, and addressing transition pathways. This increases the chances of closing the value chain by implementing novel solutions. For the water quality topic, the interacting European collaborative projects SOLUTIONS, MARS and GLOBAQUA and the NORMAN network provide best practice examples for successful applied collaborative research including multi-stakeholder involvement. They provided innovative conceptual, modelling and instrumental options for future monitoring and management of chemical mixtures and multiple stressors in European water resources. Advancement of EU water framework directive-related policies has therefore become an option.

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The European Collaborative Project SOLUTIONS developed models to provide diagnostic and prognostic capacity and fill data gaps for chemicals of emerging concern

2019. Jos van Gils (et al.). Environmental Sciences Europe 31 (1)

Artikel

The European Union Water Framework Directives aims at achieving good ecological status in member states' water bodies. Insufficient ecological status could be the result of different interacting stressors, among them the presence of many thousands of chemicals. The diagnosis of the likelihood that these chemicals negatively affect the ecological status of surface waters or human health, and the subsequent development of abatement measures usually relies on water quality monitoring. This gives an incomplete picture of chemicals' contamination, due to the limited number of monitoring stations, samples and substances. Information gaps thus limit the possibilities to protect against and effectively manage chemicals in aquatic ecosystems. The EU FP7 SOLUTIONS project has developed and validated a collection of integrated models (Model Train) to increase our understanding of issues related to emerging chemicals in Europe's river basins and to complement information and knowledge derived from field data. Unlike pre-existing models, the Model Train is suitable to model mixtures of thousands of chemicals, to better approach a real-life mixture exposure situation. It can also be used to model new chemicals at a stage where not much is known about them. The application of these models on a European scale provides temporally and spatially variable concentration data to fill gaps in the space, time and substance domains left open by water quality monitoring, and it provides homogeneous data across Europe where water quality data from monitoring are missing. Thus, it helps to avoid overlooking candidate chemicals and possible hot spots for management intervention. The application of the SOLUTIONS Model Train on a European scale presents a relevant line of evidence for water system level prognostic and diagnostic impact assessment related to chemical pollution. The application supports the design of cost-effective programmes of measures by helping to identify the most affected sites and the responsible substances, by evaluating alternative abatement options and by exploring the consequences of future trends.

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The concept of essential use for determining when uses of PFASs can be phased out

2019. Ian T. Cousins (et al.). Environmental Science 21 (11), 1803-1815

Artikel

Because of the extreme persistence of per- and polyfluoroalkyl substances (PFASs) and their associated risks, the Madrid Statement argues for stopping their use where they are deemed not essential or when safer alternatives exist. To determine when uses of PFASs have an essential function in modern society, and when they do not, is not an easy task. Here, we: (1) develop the concept of essential use based on an existing approach described in the Montreal Protocol, (2) apply the concept to various uses of PFASs to determine the feasibility of elimination or substitution of PFASs in each use category, and (3) outline the challenges for phasing out uses of PFASs in society. In brief, we developed three distinct categories to describe the different levels of essentiality of individual uses. A phase-out of many uses of PFASs can be implemented because they are not necessary for the betterment of society in terms of health and safety, or because functional alternatives are currently available that can be substituted into these products or applications. Some specific uses of PFASs would be considered essential because they provide for vital functions and are currently without established alternatives. However, this essentiality should not be considered as permanent; rather, constant efforts are needed to search for alternatives. We provide a description of several ongoing uses of PFASs and discuss whether these uses are essential or non-essential according to the three essentiality categories. It is not possible to describe each use case of PFASs in detail in this single article. For follow-up work, we suggest further refining the assessment of the use cases of PFASs covered here, where necessary, and expanding the application of this concept to all other uses of PFASs. The concept of essential use can also be applied in the management of other chemicals, or groups of chemicals, of concern.

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Toward a Comprehensive Global Emission Inventory of C-4-C-10 Perfluoroalkanesulfonic Acids (PFSAs) and Related Precursors: Focus on the Life Cycle of C-6- and C-10-Based Products

2019. Justin M. Boucher (et al.). Environmental Science and Technology Letters 6 (1), 1-7

Artikel

A first global emission inventory of C-4-C-10 perfluoroalkanesulfonic acids (PFSAs) released during the life cycle of perfluorohexanesulfonyl fluoride (PHxSF)- and perfluorodecanesulfonyl fluoride (PDSF)-based products is presented. This study complements previous research on emissions of PFSAs that focused largely on the life cycle of perfluorooctanesulfonyl fluoride (POSF) and its derivatives. It reviews and integrates existing information about the life cycle of PHxSF, PDSF, and their derivatives; the limited data available in the public domain point to potentially significant global production, uses, and releases of these substances. Between 1958 and 2015, ranges of total emissions of perfluorohexanesulfonic acid (PFHxS) and perfluorodecanesulfonic acid (PFDS) are estimated to be 120-1022 and 38-378 metric tons, respectively. With the new emission estimates as inputs in a global multimedia environmental fate model (CliMoChem), the model-derived environmental concentrations well capture the reported field concentrations, providing strong support for the plausibility of the developed emission inventories. The results highlight the ongoing environmental exposure to these substances and the need for more detailed data in the public domain about their production levels and uses.

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Why is high persistence alone a major cause of concern?

2019. Ian T. Cousins (et al.). Environmental Science 21 (5), 781-792

Artikel

Persistence is a hazard criterion for chemicals enshrined in chemical regulation worldwide. In this paper, we argue that the higher the persistence of a chemical, the greater the emphasis that it should be given in chemicals assessment and decision making. We provide case studies for three classes of highly persistent chemicals (chlorofluorocarbons, polychlorinated biphenyls, and per-and polyfluoroalkyl substances) to exemplify problems unique to highly persistent chemicals, despite their otherwise diverse properties. Many well-known historical chemical pollution problems were the result of the release of highly persistent chemicals. Using evaluative modeling calculations, we demonstrate that if a chemical is highly persistent, its continuous release will lead to continuously increasing contamination irrespective of the chemical's physical-chemical properties. We argue that these increasing concentrations will result in increasing probabilities of the occurrence of known and unknown effects and that, once adverse effects are identified, it will take decades, centuries or even longer to reverse contamination and therefore effects. Based on our findings we propose that high persistence alone should be established as a sufficient basis for regulation of a chemical, which we term the P-sufficient approach. We argue that regulation on high persistence alone is not over-precautionary given the historical and ongoing problems that persistent chemicals have caused. Regulation of highly persistent chemicals, for example by restriction of emissions, would not only be precautionary, but would serve to prevent poorly reversible future impacts.

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Comparing the toxic potency in vivo of long-chain perfluoroalkyl acids and fluorinated alternatives

2018. Melissa Ines Gomis Ferreira (et al.). Environment International 113, 1-9

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Since 2000, long-chain perfluoroalkyl acids (PFAAs) and their respective precursors have been replaced by numerous fluorinated alternatives. The main rationale for this industrial transition was that these alternatives were considered less bioaccumulative and toxic than their predecessors. In this study, we evaluated to what extent differences in toxicological effect thresholds for PFAAs and fluorinated alternatives, expressed as administered dose, were confounded by differences in their distribution and elimination kinetics. A dynamic one-compartment toxicokinetic (TK) model for male rats was constructed and evaluated using test data from toxicity studies for perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), perfluoroctanesulfonic acid (PFOS) and ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate (GenX). Dose-response curves of liver enlargement from sub-chronic oral toxicity studies in male rats were converted to internal dose in serum and in liver to examine the toxicity ranking of PFAAs and fluorinated alternatives. Converting administered doses into equivalent serum and liver concentrations reduced the variability in the dose-response curves for PFBA, PFHxA, PFOA and GenX. The toxicity ranking using modeled serum (GenX>PFOA>PFHxA>PFBA) and liver (GenX>PFOA≈PFHxA≈PFBA) concentrations indicated that some fluorinated alternatives have similar or higher toxic potency than their predecessors when correcting for differences in toxicokinetics. For PFOS and perfluorobutane sulfonic acid (PFBS) the conversion from administered dose to serum concentration equivalents did not change the toxicity ranking. In conclusion, hazard assessment based on internal exposure allows evaluation of toxic potency and bioaccumulation potential independent of kinetics and should be considered when comparing fluorinated alternatives with their predecessors.

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Efficient removal of perfluorooctane sulfonate from aqueous film-forming foam solution by aeration-foam collection

2018. Pingping Meng (et al.). Chemosphere 203, 263-270

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Aqueous film-forming foams (AFFFs) used in fire-fighting are one of the main contamination sources of perfluorooctane sulfonate (PFOS) to the subterranean environment, requiring high costs for remediation. In this study, a method that combined aeration and foam collection was presented to remove PFOS from a commercially available AFFF solution. The method utilized the strong surfactant properties of PFOS that cause it to be highly enriched at air-water interfaces. With an aeration flow rate of 75 mL/min, PFOS removal percent reached 96% after 2 h, and the PFOS concentration in the collected foam was up to 6.5 mmol/L, beneficial for PFOS recovery and reuse. Increasing the aeration flow rate, ionic strength and concentration of co-existing surfactant, as well as decreasing the initial PFOS concentration, increased the removal percents of PFOS by increasing the foam volume, but reduced the enrichment of PFOS in the foams. With the assistance of a co-existing hydrocarbon surfactant, PFOS removal percent was above 99.9% after aeration-foam collection for 2 h and the enrichment factor exceeded 8400. Aeration-foam collection was less effective for short-chain perfluoroalkyl substances due to their relatively lower surface activity. Aeration-foam collection was found to be effective for the removal of high concentrations of PFOS from AFFF-contaminated wastewater, and the concentrated PFOS in the collected foam can be reused.

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Facing the rain after the phase out: Performance evaluation of alternative fluorinated and non-fluorinated durable water repellents for outdoor fabrics

2018. Steffen Schellenberger (et al.). Chemosphere 193, 675-684

Artikel

Fluorinated durable water repellent (DWR) agents are used to obtain water and stain repellent textiles. Due to the on-going phase-out of DWRs based on side-chain fluorinated polymers (SFP) with long perfluoroalkyl chains, the textile industry lacks suitable alternatives with comparable material characteristics. The constant development and optimization of SFPs for textile applications initiated more than half a century ago has resulted in a robust and very efficient DWR technology and textiles with exceptional hydro- and oleophobic properties. The industry is now in the predicament that the long-chain SFPs with the best technical performance have undesirable toxicological and environmental behavior. This study provides a comprehensive overview of the technical performance of presently available fluorinated and non-fluorinated DWRs as part of a chemical alternatives assessment (CAA). The results are based on a study with synthetic outdoor fabrics treated with alternative DWRs and tested for repellency using industrial standard and complementary methods. Using this approach, the complex structure-property relationships of DWR polymers could be explained on a molecular level. Both short chain SFPs and non-fluorinated DWRs showed excellent water repellency and durability in some cases while short-chain SFPs were more robust of the alternatives to long-chain SFPs. A strong decline in oil repellency and durability with perfluoroalkyl chain length was shown for SFP DWRs. Non-fluorinated alternatives

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Longitudinal trends of per- and polyfluoroalkyl substances in children's serum

2018. Jani Koponen (et al.). Environment International 121, 591-599

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Studies suggest negative health impacts from early life exposure to per- and polyfluoroalkyl substances (PFASs). However, information on longitudinal exposure to PFASs during childhood is scarce for background-exposed individuals. This study sought to fill this gap by investigating children's longitudinal exposure trends through measurement of PFAS serum concentrations and calculation of body burdens (mu g, total in body). Blood of 54 Finnish children was sampled 2005-2015 and analyzed for 20 PFASs at 1, 6 and 10.5 years of age. The body burden was calculated by multiplying the serum concentration by the volume of distribution and the bodyweight for each individual. Associations between serum concentrations or body burdens and parameters, such as sex, breastfeeding duration, body mass index as well as indoor dust and air PFAS concentrations, were evaluated. Serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) decreased significantly (p < 0.001) with age. In contrast to serum concentrations, body burdens stayed unchanged or even increased significantly (p < 0.05), except for PFOA in female children. Breastfeeding duration was positively correlated (p < 0.001) with serum concentrations of PFHxS, PFOS, PFOA and PFNA at 1 year of age. Some associations were found at 10.5 years with sex and indoor PFAS concentrations. Observations of longitudinal decreasing trends of serum concentrations can be misleading for understanding exposure levels from external media during childhood, as the serum concentration is influenced by parallel temporal changes and growth dilution. Body burdens account for growth dilution and thus better reflect differences in early-life to adolescence exposure than serum concentrations.

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Multi-pathway human exposure assessment of phthalate esters and DINCH

2018. Georgios Giovanoulis (et al.). Environment International 112, 115-126

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Phthalate esters are substances mainly used as plasticizers in various applications. Some have been restricted and phased out due to their adverse health effects and ubiquitous presence, leading to the introduction of alternative plasticizers, such as DINCH. Using a comprehensive dataset from a Norwegian study population, human exposure to DMP, DEP, DnBP, DiBP, BBzP, DEHP, DINP, DIDP, DPHP and DINCH was assessed by measuring their presence in external exposure media, allowing an estimation of the total intake, as well as the relative importance of different uptake pathways. Intake via different uptake routes, in particular inhalation, dermal absorption, and oral uptake was estimated and total intake based on all uptake pathways was compared to the calculated intake from biomonitoring data. Hand wipe results were used to determine dermal uptake and compared to other exposure sources such as air, dust and personal care products. Results showed that the calculated total intakes were similar, but slightly higher than those based on biomonitoring methods by 1.1 to 3 times (median), indicating a good understanding of important uptake pathways. The relative importance of different uptake pathways was comparable to other studies, where inhalation was important for lower molecular weight phthalates, and negligible for the higher molecular weight phthalates and DINCH. Dietary intake was the predominant exposure route for all analyzed substances. Dermal uptake based on hand wipes was much lower (median up to 2000 times) than the total dermal uptake via air, dust and personal care products. Still, dermal uptake is not a well-studied exposure pathway and several research gaps (e.g. absorption fractions) remain. Based on calculated intakes, the exposure for the Norwegian participants to the phthalates and DINCH was lower than health based limit values. Nevertheless, exposure to alternative plasticizers, such as DPHP and DINCH, is expected to increase in the future and continuous monitoring is required.

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Perfluoroalkyl acids and their precursors in floor dust of children's bedrooms - Implications for indoor exposure

2018. Kerstin Winkens (et al.). Environment International 119, 493-502

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We analysed floor dust samples from 65 children's bedrooms in Finland collected in 2014/2015 for 62 different per- and polyfluoroalkyl substances (PFASs) with a simple and highly efficient method. Validation results from the analysis of standard reference material (SRM) 2585 were in good agreement with literature data, while 24 PFASs were quantified for the first time. In the dust samples from children's bedrooms, five perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctane sulfonic acid (PFOS) were detected in more than half of the samples with the highest median concentration of 5.26 ng/g for perfluorooctanoic acid (PFOA). However, the dust samples were dominated by polyfluoroalkyl phosphoric acid esters (PAPs) and fluorotelomer alcohols (FTOHs) (highest medians: 53.9 ng/g for 6:2 diPAP and 45.7 ng/g for 8:2 FTOH). Several significant and strong correlations (up to p = 0.95) were found among different PFASs in dust as well as between PFASs in dust and air samples (previously published) from the same rooms. The logarithm of dust to air concentrations (log K-dust/air) plotted against the logarithm of the octanol-air partition coefficient (log K-oa) resulted in a significant linear regression line with R-2 > 0.88. Higher dust levels of PFOS were detected in rooms with plastic flooring material in comparison to wood (p < 0.05). Total estimated daily intakes via dust (EDIdust) and air (EDIair) of perfluoroalkyl acids (PFAA), including biotransformation of precursors to PFAAs, were calculated for 10.5-year-old children. The total EDIdust, for PFOA and PFOS were estimated to be 0.007 ng/kg bw/day and 0.006 ng/kg bw/day, respectively, in an intermediate exposure scenario. The sum of the total EDIs for all PFAAs was slightly higher for dust than air (0.027 and 0.019 ng/kg bw/day). Precursor biotransformation was generally important for total PFOS intake, while for the PFCAs, FTOH biotransformation was estimated to be important for air, but not for dust exposure.

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Polychlorinated biphenyls (PCBs) as sentinels for the elucidation of Arctic environmental change processes: a comprehensive review combined with ArcRisk project results

2018. Pernilla Carlsson (et al.). Environmental Science and Pollution Research 25 (23), 22499-22528

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Polychlorinated biphenyls (PCBs) can be used as chemical sentinels for the assessment of anthropogenic influences on Arctic environmental change. We present an overview of studies on PCBs in the Arctic and combine these with the findings from ArcRisk-a major European Union-funded project aimed at examining the effects of climate change on the transport of contaminants to and their behaviour of in the Arctic-to provide a case study on the behaviour and impact of PCBs over time in the Arctic. PCBs in the Arctic have shown declining trends in the environment over the last few decades. Atmospheric long-range transport from secondary and primary sources is the major input of PCBs to the Arctic region. Modelling of the atmospheric PCB composition and behaviour showed some increases in environmental concentrations in a warmer Arctic, but the general decline in PCB levels is still the most prominent feature. 'Within-Arctic' processing of PCBs will be affected by climate change-related processes such as changing wet deposition. These in turn will influence biological exposure and uptake of PCBs. The pan-Arctic rivers draining large Arctic/sub-Arctic catchments provide a significant source of PCBs to the Arctic Ocean, although changes in hydrology/sediment transport combined with a changing marine environment remain areas of uncertainty with regard to PCB fate. Indirect effects of climate change on human exposure, such as a changing diet will influence and possibly reduce PCB exposure for indigenous peoples. Body burdens of PCBs have declined since the 1980s and are predicted to decline further.

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Spatial variation in the atmospheric deposition of perfluoroalkyl acids: source elucidation through analysis of isomer patterns

2018. Jana H. Johansson (et al.). Environmental Science 20 (7), 997-1006

Artikel

To evaluate the relevance of different proposed sources of perfluoroalkyl acids (PFAAs) to air, their isomer patterns were analyzed in deposition samples collected from five geographical locations: two urban sites in China (>360 km from known operational fluorochemical manufacturing facilities), one remote marine site in the Azores archipelago and two Swedish sites representing urban and background conditions. Despite variable contributions from linear perfluorooctanoic acid (PFOA) in the samples, the pattern of branched PFOA isomers was similar to those of technical standards manufactured using electrochemical fluorination (ECF). This indicates that atmospheric fate processes have little influence on the isomer profiles of PFOA and that the relative contribution of PFOA manufactured using ECF (typically 20-26% branched isomers) and telomerization (typically one single linear isomer) can be determined in atmospheric deposition samples by analyzing the proportions of branched and linear isomers. In Chinese samples, branched isomers contributed 15-25% to the total loading of PFOA, indicating that the samples were dominated by ECF PFOA. Samples in the Azores had 8-10% contribution from branched PFOA isomers, indicating an approximately equal influence of ECF and telomer sources. Only three of the samples collected in Sweden displayed a quantifiable contribution from branched PFOA isomers (8-13% of overall PFOA loading in the samples). One branched PFNA isomer was observed in samples from the marine sites. Direct manufacturing discharges, transport of sea spray aerosols and degradation of precursors are all suggested to be contributing sources, albeit to different extents, to PFAAs in air at the different geographical locations where precipitation was sampled.

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What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review

2018. Magnus Land (et al.). Environmental Evidence 7 (1)

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Background: There is a concern that continued emissions of man-made per-and polyfluoroalkyl substances (PFASs) may cause environmental and human health effects. Now widespread in human populations and in the environment, several PFASs are also present in remote regions of the world, but the environmental transport and fate of PFASs are not well understood. Phasing out the manufacture of some types of PFASs started in 2000 and further regulatory and voluntary actions have followed. The objective of this review is to understand the effects of these actions on global scale PFAS concentrations. Methods: Searches for primary research studies reporting on temporal variations of PFAS concentrations were performed in bibliographic databases, on the internet, through stakeholder contacts and in review bibliographies. No time, document type, language or geographical constraints were applied in the searches. Relevant subjects included human and environmental samples. Two authors screened all retrieved articles. Dual screening of 10% of the articles was performed at title/abstract and full-text levels by all authors. Kappa tests were used to test consistency. Relevant articles were critically appraised by four reviewers, with double checking of 20% of the articles by a second reviewer. Meta-analysis of included temporal trends was considered but judged to not be appropriate. The trends were therefore discussed in a narrative synthesis. Results: Available evidence suggests that human concentrations of perfluorooctane sulfonate (PFOS), perfluorodecane sulfonate (PFDS), and perfluorooctanoic acid (PFOA) generally are declining, while previously increasing concentrations of perfluorohexane sulfonate (PFHxS) have begun to level off. Rapid declines for PFOS-precursors (e.g. perfluorooctane sulfonamide, FOSA) have also been consistently observed in human studies. In contrast, limited data indicate that human concentrations of PFOS and PFOA are increasing in China where the production of these substances has increased. Human concentrations of longer-chained perfluoroalkyl carboxylic acids (PFCAs) with 9-14 carbon atoms are generally increasing or show insignificant trends with too low power to detect a trend. For abiotic and biological environmental samples there are no clear patterns of declining trends. Most substances show mixed results, and a majority of the trends are insignificant with low power to detect a trend. Conclusions: For electrochemically derived PFASs, including PFOS and PFOA, most human studies in North America and Europe show consistent statistically significant declines. This contrasts with findings in wildlife and in abiotic environmental samples, suggesting that declining PFOS, PFOS-precursor and PFOA concentrations in humans likely resulted from removal of certain PFASs from commercial products including paper and board used in food packaging. Increasing concentrations of long-chain PFCAs in most matrices, and in most regions, is likely due to increased use of alternative PFASs. Continued temporal trend monitoring in the environment with well-designed studies with high statistical power are necessary to evaluate the effectiveness of past and continuing regulatory mitigation measures. For humans, more temporal trend studies are needed in regions where manufacturing is most intense, as the one human study available in China is much different than in North America or Europe.

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Zurich Statement on Future Actions on Per - and Polyfluoroalkyl Substances (PFASs)

2018. Amélie Ritscher (et al.). Journal of Environmental Health Perspectives 126 (8)

Artikel

Per - and polyfluoroalkyl substances (PFASs) are man-made chemicals that contain at least one perfluoroalkyl moiety, -CnF2n-. To date, over 4,000 unique PFASs have been used in technical applications and consumer products, and some of them have been detected globally in human and wildlife biomonitoring studies. Because of their extraordinary persistence, human and environmental exposure to PFASs will be a long-term source of concern. Some PFASs such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have been investigated extensively and thus regulated, but for many other PFASs, knowledge about their current uses and hazards is still very limited or missing entirely. To address this problem and prepare an action plan for the assessment and management of PFASs in the coming years, a group of more than 50 international scientists and regulators held a two-day workshop in November, 2017. The group identified both the respective needs of and common goals shared by the scientific and the policy communities, made recommendations for cooperative actions, and outlined how the science-policy interface regarding PFASs can be strengthened using new approaches for assessing and managing highly persistent chemicals such as PFASs.

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A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)?

2017. Zhanyun Wang (et al.). Environmental Science and Technology 51 (5), 2508-2518

Artikel

More than 3000 per- and polyfluoroalkyl substances (PFASs) are, or have been, on the global market, yet most research and regulation continues to focus on a limited selection of rather well-known long-chain FASs, particularly perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and their precursors. Continuing to overlook the vast majority of other PFASs is a major concern for society. We provide recommendations for how to proceed with research and cooperation to tackle the vast number of PFASs on the market and in the environment.

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Can the use of deactivated glass fibre filters eliminate sorption artefacts associated with active air sampling of perfluorooctanoic acid?

2017. Jana H. Johansson, Urs Berger, Ian T. Cousins. Environmental Pollution 224, 779-786

Artikel

Experimental work was undertaken to test whether gaseous perfluorooctanoic acid (PFOA) sorbs to glassfibre filters (GFFs) during air sampling, causing an incorrect measure of the gas-particle equilibriumdistribution. Furthermore, tests were performed to investigate whether deactivation by siliconisationprevents sorption of gaseous PFOA to filter materials. An apparatus was constructed to closely simulate ahigh-volume air sampler, although with additional features allowing introduction of gaseous test compoundsinto an air stream stripped from particles. The set-up enabled investigation of the sorption ofgaseous test compounds to filter media, eliminating any contribution from particles. Experiments wereperformed under ambient outdoor air conditions at environmentally relevant analyte concentrations.The results demonstrate that gaseous PFOA sorbs to GFFs, but that breakthrough of gaseous PFOA on theGFFs occurs at trace-level loadings. This indicates that during high volume air sampling, filters do notquantitatively capture all the PFOA in the sampled air. Experiments with siliconised GFFs showed thatthis filter pre-treatment reduced the sorption of gaseous PFOA, but that sorption still occurred atenvironmentally relevant air concentrations. We conclude that deactivation of GFFs does not allow forthe separation of gaseous and particle bound perfluorinated carboxylic acids (PFCAs) during active airsampling. Consequently, the well-recognised theory that PFCAs do not prevail as gaseous species in theatmosphere may be based on biased measurements. Caution should be taken to ensure that this artefactwill not bias the conclusions of future field studies.

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Early life exposure to per- and polyfluoroalkyl substances (PFASs): A critical review

2017. Kerstin Winkens (et al.). Emerging Contaminants 3 (2), 55-68

Artikel

Due to the dynamic developmental processes during pregnancy, infancy, childhood and adolescence, exposure to PFASs is hypothesized to have the most pronounced negative effects during this period. In this review we critically evaluate the current state of the science regarding human early life exposure processes (until 18 years of age) to per- and polyfluoroalkyl substances (PFASs). Efficient placental transfer of perfluoroalkyl acids (PFAAs) results in relatively high prenatal exposure compared with many neutral organic contaminants. The few biomonitoring studies that specifically target infants, toddlers and other children suggest relatively high serum concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in early life with peak concentrations occurring sometime before the child reaches 20 months. This peak in serum concentrations is most likely explained by exposure via breastfeeding, ingestion of house dust and/or specific contact events with consumer products leading to high body weight normalized estimated daily intakes (EDIs). Although children have higher EDIs of PFASs than adults, these are not always reflected by higher serum levels of PFASs in children in cross-sectional biomonitoring studies due to the confounding effect of age and birth cohort, and different exposure histories due to production changes. Longitudinal exposure studies measuring internal and external exposure (for multiple pathways and PFASs) at several time points during early life are strongly encouraged to understand temporal changes in exposure of individual children. A better quantitative understanding of early life exposure processes would help to improve the validity of epidemiological studies and allow informed decisions regarding setting of regulatory thresholds and appropriate mitigation actions.

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Estimating human exposure to perfluoroalkyl acids via solid food and drinks: Implementation and comparison of different dietary assessment methods

2017. Eleni Papadopoulou (et al.). Environmental Research 158, 269-276

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Background: Diet is a major source of human exposure to hazardous environmental chemicals, including many perfluoroalkyl acids (PFAAs). Several assessment methods of dietary exposure to PFAAs have been used previously, but there is a lack of comparisons between methods. Aim: To assess human exposure to PFAAs through diet by different methods and compare the results. Methods: We studied the dietary exposure to PFAAs in 61 Norwegian adults (74% women, average age: 42 years) using three methods: i) by measuring daily PFAA intakes through a 1-day duplicate diet study (separately in solid and liquid foods), ii) by estimating intake after combining food contamination with food consumption data, as assessed by 2-day weighted food diaries and iii) by a Food Frequency Questionnaire (FFQ). We used existing food contamination data mainly from samples purchased in Norway and if not available, data from food purchased in other European countries were used. Duplicate diet samples (n = 122) were analysed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) to quantify 15 PFAAs (11 perfluoroalkyl carboxylates and 4 perfluoroalkyl sulfonates). Differences and correlations between measured and estimated intakes were assessed. Results: The most abundant PFAAs in the duplicate diet samples were PFOA, PFOS and PFHxS and the median total intakes were 5.6 ng/day, 11 ng/day and 0.78 ng/day, respectively. PFOS and PFOA concentrations were higher in solid than liquid samples. PFOS was the main contributor to the contamination in the solid samples (median concentration 14 pg/g food), while it was PFOA in the liquid samples (median concentrations: 0.72 pg/g food). High intakes of fats, oils, and eggs were statistically significantly related to high intakes of PFOS and PFOA from solid foods. High intake of milk and consumption of alcoholic beverages, as well as food in paper container were related to high PFOA intakes from liquid foods. PFOA intakes derived from food diary and FFQ were significantly higher than those derived from duplicate diet, but intakes of PFOS derived from food diary and FFQ were significantly lower than those derived from duplicate diet. We found a positive and statistically significant correlation between the PFOS intakes derived from duplicate diet with those using the food diary (rho = 0.26, p-value = 0.041), but not with the FFQ. Additionally, PFOA intakes derived by duplicate diet were significantly correlated with estimated intakes from liquid food derived from the food diary (rho = 0.34, p = 0.008) and estimated intakes from the FFQ (rho = 0.25, p-value = 0.055). Conclusions: We provide evidence that a food diary or a FFQ-based method can provide comparable intake estimates to PFOS and PFOA intakes derived from a duplicate diet study. These less burdensome methods are valuable and reliable tools to assess dietary exposure to PFASs in human studies.

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Estimating uptake of phthalate ester metabolites into the human nail plate using pharmacokinetic modelling

2017. Thuy T. Bui (et al.). Environment International 100, 148-155

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There is a lack of knowledge regarding uptake of phthalate esters (PEs) and other chemicals into the human nail plate and thus, clarity concerning the suitability of human nails as a valid alternative matrix for monitoring longterm exposure. In particular, the relative importance of internal uptake of phthalate metabolites (from e.g. blood) compared to external uptake pathways is unknown. This study provides first insights into the partitioning of phthalate-metabolites between blood and nail using pharmacokinetic (PK) modelling and biomonitoring data from a Norwegian cohort. A previously published PK model (Lorber PK model) was used in combination with measured urine data to predict serum concentrations of DEHP and DnBP/DiBP metabolites at steady state. Then, partitioning between blood and nail was assessed assuming equilibrium conditions and treating the nail plate as a tissue, assuming a fixed lipid and water content. Although calculated as a worst-case scenario at equilibrium, the predicted nail concentrations of metabolites were lower than the biomonitoring data by factors of 44 to 1300 depending on the metabolite. It is therefore concluded that internal uptake of phthalate metabolites from blood into nail is a negligible pathway and does not explain the observed nail concentrations. Ingtead, external uptake pathways are more likely to dominate, possibly through deposition of phthalates onto the skin/nail and subsequent metabolism. Modelling gaseous diffusive uptake of PEs from air to nail revealed that this pathway is unlikely to be important. Experimental quantification of internal and external uptake pathways of phthalates and their metabolites into the human nail plate is needed to verify these modelling results. However, based on this model, human nails are not a good indicator of internal human exposure for the phthalate esters studied.

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Historical human exposure to perfluoroalkyl acids in the United States and Australia reconstructed from biomonitoring data using population-based pharmacokinetic modelling

2017. Melissa I. Gomis (et al.). Environment International 108, 92-102

Artikel

Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) are found in the blood of humans and wildlife worldwide. Since the beginning of the 21st century, a downward trend in the human body burden, especially for PFOS and PFOA, has been observed while there is no clear temporal trend in wildlife. The inconsistency between the concentration decline in human serum and in wildlife could be indicative of a historical exposure pathway for humans linked to consumer products that has been reduced or eliminated. In this study, we reconstruct the past human exposure trends in two different regions, USA and Australia, by inferring the historical intake from cross-sectional biomonitoring data of PFOS, PFOA and PFHxS using a population-based pharmacokinetic model. For PFOS in the USA, the reconstructed daily intake peaked at 4.5 ng/kg-bw/day between 1988 and 1999 while in Australia it peaked at 4.0 ng/kg-bw/day between 1984 and 1996. For PFOA in the USA and Australia, the peak reconstructed daily intake was 1.1 ng/kg-bw/day in 1995 and 3.6 ng/kg-bw/day in 1992, respectively, and started to decline in 2000 and 1995, respectively. The model could not be satisfactorily fitted to the biomonitoring data for PFHxS within reasonable boundaries for its intrinsic elimination half-life, and thus reconstructing intakes of PFHxS was not possible. Our results indicate that humans experienced similar exposure levels and trends to PFOS and PFOA in the USA and Australia. Our findings support the hypothesis that near-field consumer product exposure pathways were likely dominant prior to the phase-out in industrialized countries. The intrinsic elimination half-life, which represents elimination processes that are common for all humans, and elimination processes unique to women (i.e., menstruation, cord-blood transfer and breastfeeding) were also investigated. The intrinsic elimination half-lives for PFOS and PFOA derived from model fitting for men were 3.8 and 2.4 years, respectively, for the USA, and 4.9 and 2 years respectively for Australia. Our results show that menstruation is a depuration pathway for PFOA for women, similarly but to a lesser extent compared to previous reports for PFOS. However menstruation, cord-blood transfer and breastfeeding together do not fully explain the apparently more rapid elimination of PFOA and PFOS by women compared to men; the intrinsic elimination half-lives in women were up to 13% lower for PFOS and up to 12% lower for PFOA compared to the corresponding half-lives in men.

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Model-predicted occurrence of multiple pharmaceuticals in Swedish surface waters and their flushing to the Baltic Seat

2017. Claudia Lindim (et al.). Environmental Pollution 223, 595-604

Artikel

An exposure assessment for multiple pharmaceuticals in Swedish surface waters was made using the STREAM-EU model. Results indicate that Metformin (27 ton/y), Paracetamol (6.9 ton/y) and Ibuprofen (2.33 ton/y) were the drugs with higher amounts reaching the Baltic Sea in 2011. 35 of the studied substances had more than 1 kg/y of predicted flush to the sea. Exposure potential given by the ratio amount of the drug exported to the sea/amount emitted to the environment was higher than 50% for 7 drugs (Piperacillin, Lorazepam, Metformin, Hydroxycarbamide, Hydrochlorothiazide, Furosemide and Cetirizine), implying that a high proportion of them will reach the sea, and below 10% for 27 drugs, implying high catchment attenuation. Exposure potentials were found to be dependent of persistency and hydrophobicity of the drugs. Chemicals with Log D > 2 had exposure potentials <10% regardless of their persistence. Chemicals with Log D < 2 had exposure potentials >35% with higher ratios typically achieved for longer half-lives. For Stockholm urban area, 17 of the 54 pharmaceuticals studied had calculated concentrations higher than 10 ng/L. Model agreement with monitored values had an r(2) = 0.62 for predicted concentrations and an r2 = 0.95 for predicted disposed amounts to sea.

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Perfluoroalkyl acids and their precursors in indoor air sampled in children's bedrooms

2017. Kerstin Winkens (et al.). Environmental Pollution 222, 423-432

Artikel

The contamination levels and patterns of perfluoroallcyl acids (PFAAs) and their precursors in indoor air of children's bedrooms in Finland, Northern Europe, were investigated. Our study is among the most comprehensive indoor air monitoring studies (n = 57) and to our knowledge the first one to analyse air in children's bedrooms for PFASs (17 PFAAs and 9 precursors, including two acrylates, 6:2 FTAC and 6:2 FTMAC). The most frequently detected compound was 8:2 fluorotelomer alcohol (8:2 FTOH) with the highest median concentration (3570 pg/m(3)). FTOH concentrations were generally similar to previous studies, indicating that in 2014/2015 the impact of the industrial transition had been minor on FTOH levels in indoor air. However, in contrast to earlier studies (with one exception), median concentrations of 6:2 FTOH were higher than 10:2 FTOH. The C8 PFAAs are still the most abundant acids, even though they have now been phased out by major manufacturers. The mean concentrations of FOSE/As, especially MeFOSE (89.9 pg/m(3)), were at least an order of magnitude lower compared to previous studies. Collectively the comparison of FTOHs, PFAAs and FOSE/FOSAs with previous studies indicates that indoor air levels of PFASs display a time lag to changes in production of several years. This is the first indoor air study investigating 6:2 FTMAC, which was frequently detected (58%) and displayed some of the highest maximum concentrations (13 000 pg/m(3)). There were several statistically significant correlations between particular house and room characteristics and PFAS concentrations, most interestingly higher EtFOSE air concentrations in rooms with plastic floors compared to wood or laminate.

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Probing the relationship between external and internal human exposure of organophosphate flame retardants using pharmacokinetic modelling

2017. Thuy T. Bui (et al.). Environmental Pollution 230, 550-560

Artikel

Human external exposure (i.e. intake) of organophosphate flame retardants (PFRs) has recently been quantified, but no link has yet been established between external and internal exposure. In this study, we used a pharmacokinetic (PK) model to probe the relationship between external and internal exposure data for three PFRs (EHDPHP, TNBP and TPHP) available for a Norwegian cohort of 61 individuals from 61 different households. Using current literature on metabolism of PFRs,, we predicted the metabolite serum/urine concentrations and compared it to measured data from the study population. Unavailable parameters were estimated using a model fitting approach (least squares method) after assigning reasonable constraints on the ranges of fitted parameters. Results showed an acceptable comparison between PK model estimates and measurements (<10-fold deviation) for EHDPHP. However, a deviation of 10-1000 was observed between PM model estimates and measurements for TNBP and TPHP. Sensitivity and uncertainty analysis on the PK model revealed that EHDPHP results showed higher uncertainty than TNBP or TPHP. However, there are indications that (1) current biomarkers of exposure (i.e. assumed metabolites) for TNBP and TPHP chemicals might not be specific and ultimately affecting the outcome of the modelling and (2) some exposure pathways might be missing. Further research, such as in vivo laboratory metabolism experiments of PFRs including identification of better biomarkers will reduce uncertainties in human exposure assessment.

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Relationships between estimated flame retardant emissions and levels in indoor air and house dust

2017. Ioannis Liagkouridis (et al.). Indoor Air 27 (3), 650-657

Artikel

A significant number of consumer goods and building materials can act as emission sources of flame retardants (FRs) in the indoor environment. We investigate the relationship between the emission source strength and the levels of 19 brominated flame retardants (BFRs) and seven organophosphate flame retardants (OPFRs) in air and dust collected in 38 indoor microenvironments in Norway. We use modeling methods to back-calculate emission rates from indoor air and dust measurements and identify possible indications of an emission-to-dust pathway. Experimentally based emission estimates provide a satisfactory indication of the relative emission strength of indoor sources. Modeling results indicate an up to two orders of magnitude enhanced emission strength for OPFRs (median emission rates of 0.083 and 0.41gh(-1) for air-based and dust-based estimates) compared to BFRs (0.52 and 0.37ngh(-1) median emission rates). A consistent emission-to-dust signal, defined as higher dust-based than air-based emission estimates, was identified for four of the seven OPFRs, but only for one of the 19 BFRs. It is concluded, however, that uncertainty in model input parameters could potentially lead to the false identification of an emission-to-dust signal.

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Toward a Comprehensive Global Emission Inventory of C-4-C-10 Perfluoroalkanesulfonic Acids (PFSAs) and Related Precursors: Focus on the Life Cycle of C-8-Based Products and Ongoing Industrial Transition

2017. Zhanyun Wang (et al.). Environmental Science and Technology 51 (8), 4482-4493

Artikel

Here a new global emission inventory of C-4-C-10 perfluoroalkanesulfonic acids (PFSAs) from the life cycle of perfluorooctanesulfonyl fluoride (POSF)-based products in 1958-2030 is presented. In particular, we substantially improve and expand the previous frameworks by incorporating missing pieces (e.g., emissions to soil through land treatment, overlooked precursors) and updating parameters (e.g., emission factors, degradation half-lives). In 1958-2015, total direct and indirect emissions of perfluorooctanesulfonic acid (PFOS) are estimated as 1228-4930 tonnes, and emissions of PFOS precursors are estimated as 1230-8738 tonnes and approximately 670 tonnes for x-perfluorooctanesulfonamides/sulfonamido ethanols (xFOSA/Es) and POSF, respectively. Most of these emissions occurred between 1958 and 2002, followed by a substantial decrease. This confirms the positive effect of the ongoing transition to phase out POSF-based products, although this transition may still require substantial time and cause substantial additional releases of PFOS (8-153 tonnes) and xFOSA/Es (4-698 tonnes) in 2016 to 2030. The modeled environmental concentrations obtained by coupling the emission inventory and a global multimedia mass-balance model generally agree well with reported field measurements, suggesting that the inventory captures the actual emissions of PFOS and xFOSA/Es for the time being despite remaining uncertainties. Our analysis of the key uncertainties and open questions of and beyond the inventory shows that, among others, degradation of side-chain fluorinated polymers in the environment and landfills can be a long-term, (potentially) substantial source of PFOS.

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Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources

2017. Werner Brack (et al.). Science of the Total Environment 576, 720-737

Artikel

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges. In support of the upcoming WFD review in 2019 the research project SOLUTIONS and the European monitoring network NORMAN has analyzed these challenges, evaluated the state-of-the-art of the science and suggested possible solutions. We give 10 recommendations to improve monitoring and to strengthen comprehensive prioritization, to foster consistent assessment and to support solution-oriented management of surface waters. The integration of effect-based tools, the application of passive sampling for bioaccumulative chemicals and an integrated strategy for prioritization of contaminants, accounting for knowledge gaps, are seen as important approaches to advance monitoring. Including all relevant chemical contaminants in more holistic chemical status assessment, using effect-based trigger values to address priority mixtures of chemicals, to better consider historical burdens accumulated in sediments and to use models to fill data gaps are recommended for a consistent assessment of contamination. Solution-oriented management should apply a tiered approach in investigative monitoring, to identify toxicity drivers, strengthen consistent legislative frameworks and apply solutions-oriented approaches that explore risk reduction scenarios before and along with risk assessment.

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Water-to-air transfer of branched and linear PFOA: Influence of pH, concentration and water type

2017. Jana H. Johansson (et al.). Emerging Contaminants 3 (1), 46-53

Artikel

The volatilisation of perfluorooctanoic acid (PFOA) was measured experimentally at a range of pH valuesusing a previously published laboratory method. Water-to-air transfer was studied for five structuralisomers, namely: the linear isomer (n-PFOA) and the four most commonly occurring branched isomers(3-, 4-, 5- and 6-PFOA). The influence of water concentration and water type on the pH-dependent waterto-air transfer was also investigated for n-PFOA. The water-to-air transfer was studied over the course of 48 h at pH values ranging from 0.2 to 5.5. Under all experimental conditions tested, the volatilisation ofPFOA was negligible at pH > 2.5. In experiments performed with MilliQ water, volatilisation increasedwith decreasing water pH. In experiments performed with tap water and lake water, maximum volatilisationwas observed at pH 1. The concentration of PFOA in water had no influence on the pH value atwhich water-to-air transfer was observed (i.e. at pH < 2.5) for the concentration range tested (0.1e50 mg/L PFOA in deionised water). Although the percentage of PFOA volatilised was significantly different forthe four branched isomers at low pH, volatilisation was not observed above pH 2.5 for any branchedisomer suggesting that all PFOA isomers have a low pKa. Overall, these laboratory results demonstratethat volatilisation of any structural isomer of PFOA from water is negligible at environmentally-relevantconditions. It is unlikely that PFOA isomers will be fractionated in the environment as a result of volatilisationbecause it is a process of negligible environmental relevance.

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A large-scale model for simulating the fate & transport of organic contaminants in river basins

2016. Claudia Lindim, J. van Gils, Ian T. Cousins. Chemosphere 144, 803-810

Artikel

We present STREAM-EU (Spatially and Temporally Resolved Exposure Assessment Model for EUropean basins), a novel dynamic mass balance model for predicting the environmental fate of organic contaminants in river basins. STREAM-EU goes beyond the current state-of-the-science in that it can simulate spatially and temporally-resolved contaminant concentrations in all relevant environmental media (surface water, groundwater, snow, soil and sediments) at the river basin scale. The model can currently be applied to multiple organic contaminants in any river basin in Europe, but the model framework is adaptable to any river basin in any continent. We simulate the environmental fate of perfluoroctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the Danube River basin and compare model predictions to recent monitoring data. The model predicts PFOS and PFOA concentrations that agree well with measured concentrations for large stretches of the river. Disagreements between the model predictions and measurements in some river sections are shown to be useful indicators of unknown contamination sources to the river basin.

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Comparative assessment of the environmental hazards of and exposure to perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs): Current knowledge, gaps, challenges and research needs

2016. Zhanyun Wang (et al.). Environment International 89-90, 235-247

Artikel

Perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs) are sub-groups of per- and polyfluoroalkyl substances (PFASs) that have been commercialized since the 1970s, particularly as defoamers in pesticide formulations and wetting agents in consumer products. Recently, C-4/C-4 PFPiA and its derivatives have been presented as alternatives to long-chain PFASs in certain applications. In this study, we systematically assess the publicly available information on the hazardous properties, occurrence, and exposure routes of PFPAs and PFPiAs, and make comparisons to the corresponding properties of their better-known carboxylic and sulfonic acid analogs (i.e. PFCAs and PFPAs). This comparative assessment indicates that [i] PFPAs likely have high persistence and long-range transport potential; [ii] PFPiAs may transform to PFPAs (and possibly PFCAs) in the environment and biota; [iii] certain PFPAs and PFPiAs can only be slowly eliminated from rainbow trout and rats, similarly to long-chain PFCAs and PFPAs; [iv] PFPAs and PFPiAs have modes-of-action that are both similar to, and different from, those of PFCAs and PFSAs; and [v] the measured levels of PFPAs/PFPiAs in the global environment and biota appear to be low in comparison to PFCAs and PFPAs, suggesting, for the time being, low risks from PFPAs and PFPiAs alone. Although risks from individual PFPAs/PFPiAs are currently low, their ongoing production and use and high persistence will lead to increasing exposure and risks over time. Furthermore, simultaneous exposure to PFPAs, PFPiAs and other PFASs may result in additive effects necessitating cumulative risk assessments. To facilitate effective future research, we highlight possible strategies to overcome sampling and analytical challenges.

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Contribution of Direct and Indirect Exposure to Human Serum Concentrations of Perfluorooctanoic Acid in an Occupationally Exposed Group of Ski Waxers

2016. Melissa I. Gomis Ferreira (et al.). Environmental Science and Technology 50 (13), 7037-7046

Artikel

The contribution of direct (i.e., uptake of perfluorooctanoic acid (PFOA) itself) and indirect (i.e., uptake of 8:2 fluorotelomer alcohol (FTOH) and metabolism to PFOA) exposure to PFOA serum concentrations was investigated using a dynamic one compartment pharmacokinetic (PK) model. The PK model was applied to six occupationally exposed ski waxers for whom direct and indirect exposures via inhalation were characterized using multiple measurements with personal air sampling devices. The model was able to predict the diverging individual temporal trends of PFOA in serum with correlation coefficients of 0.82-0.94. For the four technicians with high initial concentrations of PFOA in serum (250-1050 ng/mL), the ongoing occupational exposure (both direct and indirect) was of minor importance and net depuration of PFOA was observed throughout the ski season. An estimated average intrinsic elimination half-life of 2.4 years (1.8-3.1 years accounting for variation between technicians and model uncertainty) was derived for these technicians. The remaining two technicians, who had much lower initial serum concentrations (10-17 ng/mL), were strongly influenced by exposure during the ski season with indirect exposure contributing to 45% of PFOA serum concentrations. On the basis of these model simulations, an average metabolism yield of 0.003 (molar concentration basis; uncertainty range of 0.0006-0.01) was derived for transformation of 8:2 FTOH to PFOA. An uncertainty analysis was performed, and it was determined that the input parameters quantifying the intake of PFOA were mainly responsible for the uncertainty of the metabolism yield and the initial concentration of PFOA in serum was mainly contributing to the uncertainty of estimated serum half-lives.

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Europe-wide estuarine export and surface water concentrations of PFOS and PFOA

2016. Claudia Lindim, J. van Gils, Ian T. Cousins. Water Research 103, 124-132

Artikel

The STREAM-EU model was used to predict the water concentrations, estuarine export and retention of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the eleven most populated European river catchments to provide a European-wide perspective on the contamination by these substances. Emissions of PFOS and PFOA to those catchments were calculated based on population, wealth and wastewater treatment plant (WWTP) coverage and efficiency using a previously published method and used as model input. Our estimated emissions showed the lowest values for the Thames catchment (PFOS: 0.4 ton/y; PFOA: 0.2 ton/y) and the highest values for the Rhine for PFOS (1.6 ton/y) and for the Dnieper for PFOA (1.7 ton/y). The model predicted concentrations agreed reasonable well with the existing range of measurements, apart from for PFOA in the River Po, where there is a known historical industrial contamination, and PFOS in the Rhone River, where results were much higher than the few measurements available. It was concerning that the model predicted that the surface water EQS for PFOS (0.65 ng/L) was exceeded by a wide margin in all the eleven studied European river catchments. The total calculated riverine export to the seas from the eleven catchments was 4.5 ton/y of PFOS and 3.7 ton/y of PFOA with highest exported quantities from the Rhine (PFOS: 1.0 ton/y; PFOA: 1.0 ton/y) and Danube estuaries (PFOS: 0.9 ton/y; PFOA: 0.7 ton/y). For the seas where the rivers discharge, riverine discharge of PFOS was estimated to be 2.5-30 times more important as an input than atmospheric deposition, whereas for PFOA the opposite was true (atmospheric deposition was 2-10 times more important) except for very small seas.

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Evaluation of human pharmaceutical emissions and concentrations in Swedish river basins

2016. Claudia Lindim (et al.). Science of the Total Environment 572, 508-519

Artikel

An emissions inventory for top consumed human pharmaceuticals in Sweden was done based on national consumption data, human metabolic rates and wastewater treatment removal rates. Concentrations of pharmaceuticals in surface waters in Swedish river basins were predicted using estimated emissions from the inventory and river discharges. Our findings indicate that the top ten emitted pharmaceuticals in our study set of 54 substances are all emitted in amounts above 0.5 ton/y to both surface waters and soils. The highest emissions to water were in decreasing order for Metformin, Furosemide, Gabapentin, Atenolol and Tramadol. Predicted emissions to soils calculated with the knowledge that in Sweden sludge is mostly disposed to soil, point to the highest emissions among the studied drugs coming from, in decreasing order, Metformin, Paracetamol, Ibuprofen, Gabapentin and Atenolol. Surface water concentrations in Sweden's largest rivers, all located in low density population zones, were found to be below 10 ng/L for all substances studied. In contrast, concentrations in surface waters in Stockholm's metropolitan area, the most populous in Sweden, surpassed 100 ng/L for four substances: Atenolol, Metformin, Furosemide and Gabapentin.

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Human exposure, hazard and risk of alternative plasticizers to phthalate esters

2016. Thuy T. Bui (et al.). Science of the Total Environment 541, 451-467

Artikel

Alternative plasticizers to phthalate esters have been used for over a decade, but data regarding emissions, human exposure and health effects are limited. Here we review 20 alternative plasticizers in current use and their human exposure, hazard and risk. Physicochemical properties are collated for these diverse alternatives and log K-OW values range over 15 orders of magnitude and log K-AW and log K-OA values over about 9 orders of magnitude. Most substances are hydrophobic with low volatility and are produced in high volumes for use in multiple applications. There is an increasing trend in the total use of alternative plasticizers in Sweden compared to common phthalate esters in the last 10 years, especially for DINCH. Evaluative indoor fate modeling reveals that most alternatives are distributed to vertical surfaces (e.g. walls or ceilings). Only TXIB and GTA are predicted to be predominantly distributed to indoor air. Human exposure data are lacking and clear evidence for human exposure only exists for DEHT and DINCH, which show increasing trends in body burdens. Human intake rates are collected and compared with limit values with resulting risk ratios below 1 except for infant's exposure to ESBO. PBT properties of the alternatives indicate mostly no reasons for concern, except that TEHPA is estimated to be persistent and TCP toxic. A caveat is that non-standard toxicological endpoint results are not available and, similar to phthalate esters, the alternatives are likely pseudo-persistent. Keydata gaps for more comprehensive risk assessment are identified and include: analytical methods to measure metabolites in biological fluids and tissues, toxicological information regarding non-standard endpoints such as endocrine disruption and a further refined exposure assessment in order to consider high risk groups such as infants, toddlers and children.

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Is Ongoing Sulfluramid Use in South America a Significant Source of Perfluorooctanesulfonate (PFOS)? Production Inventories, Environmental Fate, and Local Occurrence

2016. John Löfstedt Gilljam (et al.). Environmental Science and Technology 50 (2), 653-659

Artikel

Despite international phase-out initiatives, production and use of perfluorooctanesulfonate (PFOS) and related substances continues in some countries. In Brazil, the PFOS-precursor N-ethyl perfluorooctane sulfonamide (EtFOSA) is used in Sulfluramid, a pesticide for controlling leaf-cutting ants. New data on production, environmental fate, and occurrence of Brazilian Sulfluramid are reported herein. From 2003 to 2013, Brazilian Sulfluramid manufacturing increased from 30 to 60 tonnes yr(-1) EtFOSA. During this time <1.3 tonnes yr(-1) were imported, while exports increased from similar to 0.3 to 2 tonnes yr(-1). From 2004 to 2015, most EtFOSA was exported to Argentina (7.2 tonnes), Colombia (2.07 tonnes), Costa Rica (1.13 tonnes), Equador (2.16 tonnes), and Venezuela (2.4 tonnes). Within Brazil, sales occurred primarily in the states of Minas Gerais, Sao Paulo, Mato Grosso do Sul, Espirito Santo, and Bahia. Model simulations predict EtFOSA will partition to soils, while transformation products perfluorooctane sulfonamide (FOSA) and PFOS are sufficiently mobile to leach into surface waters. In support of these predictions, up to 3400 pg L(-)1 of FOSA and up to 1100 pg L(-)1 of PFOS were measured in Brazilian surface water, while EtFOSA was not detected. The high FOSA/PFOS ratio observed here (up to 14:1) is unprecedented in the scientific literature to our knowledge. Depending on the extent of conversion of EtFOSA, cumulative Brazilian Sulfluramid production and import from 2004 to 2015 may contribute between 167 and 487 tonnes of PFOS/FOSA to the environment. These levels are clearly nontrivial and of concern since production is continuing unabated.

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Levels, Isomer Profiles, and Estimated Riverine Mass Discharges of Perfluoroalkyl Acids and Fluorinated Alternatives at the Mouths of Chinese Rivers

2016. Thanh Wang (et al.). Environmental Science and Technology 50 (21), 11584-11592

Artikel

An extensive sampling campaign was undertaken to study the levels, isomer profiles and riverine mass discharges of perfluoroalkyl acids (PFAAs) and fluorinated alternatives in 19 Chinese rivers. The levels and homologue profiles of Sigma(10)PFAAs varied considerably among the 19 rivers (mean 106; median 16.3, range 8.91240 ng/L), indicating the influence of specific point sources. Highly branched isomer profiles of perfluorooctanoic acid (1825% br-PFOA) in rivers with elevated concentrations (96352 ng/L) indicate that releases during production of PFOA by electrochemical fluorination and/or its use in fluoropolymer manufacture were the dominant sources to these rivers. The fluorinated alternatives 6:2 fluorotelomer sulfonate (detection frequency 21%, < 0.13.1 ng/L) and chlorinated polyfluoroalkyl ether sulfonate F-53B (51%, < 0.5678.5 ng/L) were also found in some rivers. The total Chinese riverine mass discharges of PFOA (mean 80.9; range 16.8168 t/y) (including monitoring data from this and other studies) were in good agreement with theoretical PFOA emission estimates (17.3203 t/y) whereas riverine mass discharges of PFOS (mean 3.6; range 1.95.6 t/y) could only account for a minor fraction of theoretically estimated PFOS releases (70 t/y). This study provides empirical evidence that emissions from Chinese point sources likely dominate the global emissions of several legacy PFASs (notably PFOA) and fluorinated alternatives (e.g., F-53B).

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Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing

2016. H. Holmquist (et al.). Environment International 91, 251-264

Artikel

Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry had to find alternatives for side-chain fluorinated polymer based durable water repellent (DWR) chemistries that incorporated long perfluoroalkyl side chains. This phase-out and subsequent substitution with alternatives has resulted in a market where both fluorinated and non-fluorinated DWRs are available. These DWR alternatives can be divided into four broad groups that reflect their basic chemistry: side-chain fluorinated polymers, silicones, hydrocarbons and other chemistries (including dendrimer and inorganic nanoparticle chemistries). In this critical review, the alternative DWRs are assessed with regard to their structural properties and connected performance, loss and degradation processes resulting in diffuse environmental emissions, and hazard profiles for selected emitted substances. Our review shows that there are large differences in performance between the alternative DWRs, most importantly the lack of oil repellency of non-fluorinated alternatives. It also shows that for all alternatives, impurities and / or degradation products of the DWR chemistries are diffusively emitted to the environment. Our hazard ranking suggests that hydrocarbon based DWR is the most environmentally benign, followed by silicone and side-chain fluorinated polymer-based DWR chemistries. Industrial commitments to reduce the levels of impurities in silicone based and side-chain fluorinated polymer based DWR formulations will lower the actual risks. There is a lack of information on the hazards associated with DWRs, in particular for the dendrimer and inorganic nanoparticle chemistries, and these data gaps must be filled. Until environmentally safe alternatives, which provide the required performance, are available our recommendation is to choose DWR chemistry on a case-by-case basis, always weighing the benefits connected to increased performance against the risks to the environment and human health.

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The precautionary principle and chemicals management: The example of perfluoroalkyl acids in groundwater

2016. Ian T. Cousins (et al.). Environment International 94, 331-340

Artikel

Already in the late 1990s microgram-per-liter levels of perfluorooctane sulfonate (PFOS) were measured in water samples from areas where fire-fighting foams were used or spilled. Despite these early warnings, the problems of groundwater, and thus drinking water, contaminated with perfluoroalkyl and polyfluoroalkyl substances (PFASs) including PFOS are only beginning to be addressed. It is clear that this PFAS contamination is poorly reversible and that the societal costs of clean-up will be high. This inability to reverse exposure in a reasonable timeframe is a major motivation for application of the precautionary principle in chemicals management. We conclude that exposure can be poorly reversible; 1) due to slow elimination kinetics in organisms, or 2) due to poorly reversible environmental contamination that leads to continuous exposure. In the second case, which is relevant for contaminated groundwater, the reversibility of exposure is not related to the magnitude of a chemical's bioaccumulation potential. We argue therefore that all PFASs entering groundwater, irrespective of their perfluoroalkyl chain length and bioaccumulation potential, will result in poorly reversible exposures and risks as well as further clean-up costs for society. To protect groundwater resources for future generations, society should consider a precautionary approach to chemicals management and prevent the use and release of highly persistent and mobile chemicals such as PFASs. (C) 2016 Elsevier Ltd. All rights reserved.

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A modeling assessment of the physicochemical properties and environmental fate of emerging and novel per- and polyfluoroalkyl substances

2015. Melissa Ines Gomis (et al.). Science of the Total Environment 505, 981-991

Artikel

Long-chain perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) are persistent, bioaccumulative, and toxic contaminants that are globally present in the environment, wildlife and humans. Phase-out actions and use restrictions to reduce the environmental release of long-chain PFCAs, PFSAs and their precursors have been taken since 2000. In particular, long-chain poly- and perfluoroalkyl substances (PFASs) are being replaced with shorter-chain homologues or other fluorinated or non-fluorinated alternatives. A key question is: are these alternatives, particularly the structurally similar fluorinated alternatives, less hazardous to humans and the environment than the substances they replace? Several fluorinated alternatives including perfluoroether carboxylic acids (PFECAs) and perfluoroether sulfonic adds (PFESAs) have beet recently identified. However, the scarcity of experimental data prevents hazard and risk assessments for these substances. In this study, we use state-of-the-art in silico tools to estimate key properties of these newly identified fluorinated alternatives. [i] COSMOtherm and SPARC ate used to estimate physicochemical properties. The US EPA EPISuite software package is used to predict degradation half-lives in air, water and soil. [ii] In combination with estimated chemical properties, a fugacity-based multimedia mass-balance unit-world model the OECD Overall Persistence (Pov) and Long-Range Transport Potential (LRTP) Screening Tool is used to assess the likely environmental fate of these alternatives. Even though the fluorinated alternatives contain some structural differences, their physicochemical properties are not significantly different from those of their predecessors. Furthermore, most of the alternatives are estimated to be similarly persistent and mobile in the environment as the long-chain PFASs. The models therefore predict that the fluorinated alternatives will become globally distributed in the environment similar to their predecessors. Although such in silico methods are coupled with uncertainties, this preliminary assessment provides enough cause for concern to warrant experimental work to better determine the properties of these fluorinated alternatives.

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Are imported consumer products an important diffuse source of PFASs to the Norwegian environment?

2015. Robin Vestergren (et al.). Environmental Pollution 198, 223-230

Artikel

The aim of this study was to measure perfluoroalkyl substances in a selection of imported consumer products (n = 45) and estimate population normalized emission rates during the use phase. 6:2 and 8:2 fluorotelomer alcohol (FTOH) were found in the highest concentrations ranging from <MDL to 374 and 163 mu g m(-2) respectively. Concentrations of FTOHs were approximately 2-3 orders of magnitude higher than those of perfluoroalkyl carboxylic acids (PFCAs). Although perfluorooctane sulfonate (PFOS) was detected in one carpet sample at 1.7 mu g m(-2), the majority of samples complied with regulatory limits for PFOS in the EU. Population normalized emission rates of perfluorooctanoic acid, 6:2 FTOH and 8:2 FTOH from imported consumer products were estimated to be 6.6, 2130 and 197 mu g year(-1) capita(-1) respectively for the intermediate emistion scenario. The results from this study suggest that emissions from imported products would have a small impact on the environmental concentrations of perfluoroalkyl acids on a regional scale.

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Comment on “Fluorotechnology Is Critical to Modern Life: The FluoroCouncil Counterpoint to the Madrid Statement”

2015. Ian T. Cousins (et al.). Journal of Environmental Health Perspectives 123 (7), A170-A170

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Estimating emissions of PFOS and PFOA to the Danube River catchment and evaluating them using a catchment-scale chemical transport and fate model

2015. Claudia Lindim, Ian T. Cousins, J. vanGils. Environmental Pollution 207, 97-106

Artikel

Novel approaches for estimating the emissions of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) to surface waters are explored. The Danube River catchment is used to investigate emissions contributing to riverine loads of PFOS and PFOA and to verify the accuracy of estimates using a catchment-scale dynamic fugacity-based chemical transport and fate model (STREAM-EU; Spatially and Temporally Resolved Exposure Assessment Model for European basins). Model accuracy evaluation performed by comparing STREAM-EU predicted concentrations and monitoring data for the Danube and its tributaries shows that the best estimates for PFOS and PFOA emissions in the Danube region are obtained by considering the combined contributions of human population, wealth (based on local gross domestic product (GDP)) and wastewater treatment. Human population alone cannot explain the levels of PFOS and PFOA found in the Danube catchment waters. Introducing wealth distribution information in the form of local GDPs improves emission estimates markedly, likely by better representing emissions resulting from consumer trends, industrial and commercial sources. For compounds such as PFOS and PFOA, whose main sink and transport media is the aquatic compartment, a major source to freshwater are wastewater treatment plants. Introducing wastewater treatment information in the emission estimations also further improves emission estimates.

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Estimating human exposure to PFOS isomers and PFCA homologues: The relative importance of direct and indirect (precursor) exposure

2015. Wouter A. Gebbink, Urs Berger, Ian T. Cousins. Environment International 74, 160-169

Artikel

Contributions of direct and indirect (via precursors) pathways of human exposure to perfluorooctane sulfonic acid (PFOS) isomers and perfluoroalkyl carboxylic acids (PFCAs) are estimated using a Scenario-Based Risk Assessment (SceBRA) modelling approach. Monitoring data published since 2008 (including samples from 2007) are used. The estimated daily exposures (resulting from both direct and precursor intake) for the general adult population are highest for PFOS and perfluorooctanoic acid (PFOA), followed by perfluorohexanoic add (PFHxA) and perfluorodecanoic acid (PFDA), while lower daily exposures are estimated for perfluorobutanoic acid (PFBA) and perfluorododecanoic acid (PFDoDA). The precursor contributions to the individual perfluoroalkyl acid (PFAA) daily exposures are estimated to be 11-33% for PFOS, 0.1-2.5% for PFBA, 3.7-34% for PFHxA, 13-64% for PFOA, 5.2-66% for PFDA, and 0.7-25% for PFDoDA (ranges represent estimated precursor contributions in a low- and high-exposure scenario). For PFOS, direct intake via diet is the major exposure pathway regardless of exposure scenario. For PFCAs, the dominant exposure pathway is dependent on perfluoroalkyl chain length and exposure scenario. Modelled PFOS and PFOA concentrations in human serum using the estimated intakes from an intermediate-exposure scenario are in agreement with measured concentrations in different populations. The isomer pattern of PFOS resulting from total intakes (direct and via precursors) is estimated to be enriched with linear PFOS (84%) relative to technical PFOS (70% linear). This finding appears to be contradictory to the observed enrichment of branched PFOS isomers in recent human serum monitoring studies and suggests that either external exposure is not fully understood (e.g. there are unknown precursors, missing or poorly quantified exposure pathways) and/or that there is an incomplete understanding of the isomer-specific human pharmacokinetic processes of PFOS, its precursors and intermediates.

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Hazard assessment of fluorinated alternatives to long-chain perfluoroalkyl acids (PFAAs) and their precursors: Status quo, ongoing challenges and possible solutions

2015. Zhanyun Wang (et al.). Environment International 75, 172-179

Artikel

Because of concerns over the impact of long-chain perfluoroalkyl acids (PFAAs) on humans and the environment, PFAAs and their precursors are being substituted by alternative substances including fluorinated alternatives that are structurally similar to the substances they replace. Using publicly accessible information, we aimed to identify the status quo of the hazard assessment of identified fluorinated alternatives, to analyze possible systemic shortcomings of the current industrial transition to alternative substances, and to outline possible solutions. Fluorinated alternatives, particularly short-chain PFAAs and perfluoroether carboxylic and sulfonic acids (PFECAs and PFESAs), possess high environmental stability and mobility implying that they have a high global contamination potential. In addition to their potential for causing global exposures, certain fluorinated alternatives have been identified as toxic and are thus likely to pose global risks to humans and the environment. Various factors, particularly the information asymmetry between industry and other stakeholders, have contributed to the current lack of knowledge about the risks posed by fluorinated alternatives. Available cases show that a non-fluorinated substitution strategy (employing either chemical or functionality substitutions) can be a possible long-term, sustainable solution and needs to be further developed and assessed.

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Impacts on human health in the Arctic owing to climate-induced changes in contaminant cycling - The EU ArcRisk project policy outcome

2015. Jozef M. Pacyna (et al.). Environmental Science and Policy 50, 200-213

Artikel

Results of the EU ArcRisk project on human health impacts in the Arctic owing to climate-induced changes in contaminant cycling are summarized in the context of their policy application. The question on how will climate change affect the transport of selected persistent organic pollutants (POPS) and mercury, both to and within the Arctic has been addressed, as well as the issue of human health impacts of these pollutants in the Arctic in relation to exposed local populations. It was concluded that better characterization of primary and secondary sources of POPs and more accurate quantification of current and future releases of POPs from these sources are needed for better prediction of environmental exposure to these contaminants and interpretation of monitoring data. Further improvement of fate and transport modeling in the physical environment is necessary in order to consider in the models not only the relatively well studied direct effects of climate change (e.g., changes in temperature, ice and snow cover, precipitation, wind speed and ocean currents) on contaminants fate and behavior but also indirect effects, e.g., alterations in carbon cycling, catchment hydrology, land use, vegetation cover, etc. Long-term environmental monitoring of POPs (at multiple sampling stations within and outside the Arctic and at regular sampling intervals facilitates temporal trend analysis) and measurements of concentrations in human milk and blood plasma are needed. Finally, more information should be gathered on the human health effects of newly identified POPs, such as perfluorooctane-sulfonic acid (PFOS), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and other substances with POP-like characteristics, particularly the effects on very young (including fetus) and elderly subgroups of the human population. The Arc Risk developed methodologies and tools that can be used in further studies to resolve various uncertainties already defined in the analysis of climate change impacts on POPs and mercury behavior and effects in the Arctic. The ArcRisk project has also developed very valuable databases that can be regarded as a starting point in further studies.

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Perfluoroalkyl acids in municipal landfill leachates from China: Occurrence, fate during leachate treatment and potential impact on groundwater

2015. Hong Yan (et al.). Science of the Total Environment 524, 23-31

Artikel

Raw and treated landfill leachate samples were collected from 5 municipal landfill sites in China to measure the concentrations and contamination profile of perfluoroalkyl acids (PFAAs) in leachate during different steps of treatment. The total concentration of PFAAs (Sigma PFAAs) ranged from 7280 to 292,000 ng L-1 in raw leachate and from 98.4 to 282,000 ng L-1 in treated leachate. The dominant compounds measured were PFOA (mean contribution 28.8% and 36.8% in raw and treated leachate, respectively) and PFBS (26.1% and 40.8% in raw and treated leachate, respectively). A calculation of mass flows during the leachate treatment processes showed that the fate of individual PFAAs was substance and treatment-specific. The Chinese national leakage of Sigma PFAAs to groundwater from landfill leachate was estimated to be 3110 kg year(-1), which is a significant environmental release that is potentially threatening the sustainable use of groundwater as a drinking water source.

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Physical-chemical properties and evaluative fate modelling of 'emerging' and 'novel' brominated and organophosphorus flame retardants in the indoor and outdoor environment

2015. Ioannis Liagkouridis, Anna Palm Cousins, Ian T. Cousins. Science of the Total Environment 524, 416-426

Artikel

Several groups of flame retardants (FRs) have entered the market in recent years as replacements for polybrominated diphenyl ethers (PBDEs), but little is known about their physical-chemical properties or their environmental transport and fate. Here we make best estimates of the physical-chemical properties and undertake evaluative modelling assessments (indoors and outdoors) for 35 so-called 'novel' and 'emerging' brominated flame retardants (BFRs) and 22 organophosphorus flame retardants (OPFRs). A QSPR (Quantitative Structure-Property Relationship) based technique is used to reduce uncertainty in physical-chemical properties and to aid property selection for modelling, but it is evident that more, high quality property data are required for improving future assessments. Evaluative modelling results show that many of the alternative FRs, mainly alternative BFRs and some of the halogenated OPFRs, behave similarly to the PBDEs both indoors and outdoors. These alternative FRs exhibit high overall persistence (Pov), long-range transport potential (LRTP) and POP-like behaviour and on that basis cannot be regarded as suitable replacements to PBDEs. A group of low molecular weight alternative BFRs and non-halogenated OPFRs show a potentially better environmental performance based on Pov and LRTP metrics. Results must be interpreted with caution though since there are significant uncertainties and limited data to allow for thorough model evaluation. Additional environmental parameters such as toxicity and bioaccumulative potential as well as functionality issues should be considered in an industrial substitution strategy.

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Response to Comment on Enhanced Elimination of Perfluorooctane Sulfonic Acid by Menstruating Women: Evidence from Population-based Pharmacokinetic Modeling

2015. Fiona Wong (et al.). Environmental Science and Technology 49 (9), 5838-5839

Artikel

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The SOLUTIONS project: Challenges and responses for present and future emerging pollutants in land and water resources management

2015. Werner Brack (et al.). Science of the Total Environment 503, 22-31

Artikel

SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7). The project aims to deliver a conceptual framework to support the evidence-based development of environmental policies with regard to water quality. SOLUTIONS will develop the tools for the identification, prioritisation and assessment of those water contaminants that may pose a risk to ecosystems and human health. To this end, a new generation of chemical and effect-based monitoring tools is developed and integrated with a full set of exposure, effect and risk assessment models. SOLUTIONS attempts to address legacy, present and future contamination by integrating monitoring and modelling based approaches with scenarios on future developments in society, economy and technology and thus in contamination. The project follows a solutions-oriented approach by addressing major problems of water and chemicals management and by assessing abatement options. SOLUTIONS takes advantage of the access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and puts major efforts on stakeholder dialogue and support. Particularly, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations are directly supported. with consistent guidance for the early detection, identification, prioritisation, and abatement of chemicals in the water cycle. SOLUTIONS will give a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. The SOLUTIONS approach is expected to provide transparent and evidence-based candidates or River Basin Specific Pollutants in the case study basins and to assist future review of priority pollutants under the WFD as well as potential abatement options.

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What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review protocol

2015. Magnus Land (et al.). Environmental Evidence 4 (1)

Artikel

Background

There is a growing concern in Sweden and elsewhere that continued emissions of per- and polyfluoroalkyl substances (PFASs) may cause environmental as well as human health effects. PFASs are a broad class of man-made substances that have been produced and used in both commercial products and industrial processes for more than 60 years. Although the production and use of some PFASs has been phased-out in some parts of the world, it is not known what effect these actions to date have had on PFAS concentrations in the environment. Owing to the wide diversity of PFASs, it is difficult to generalize their properties, environmental fate and production histories. However, the strength and stability of the C-F bond renders the perfluoroalkyl moieties resistant to heat and environmental degradation. Several PFASs are now occurring even in very remote areas in large parts of the world, but the environmental transport and fate of substances within this group is not well understood. A systematic review may be able to determine whether the concentrations of these substances in different environments are changing in any particular direction with time, and whether the phase-outs have had any effects on the concentration trends.

Methods

Searches for primary research studies reporting on temporal variations of PFAS concentrations in the environment will be performed in the scientific literature as well as in other reports. Relevant samples include both abiotic and biological samples including humans. No particular time, document type, language or geographical constraints will be applied. Two authors will screen all retrieved articles. Double screening of about 10% of the articles will be performed by all authors at both title/abstract and full-text levels. Kappa tests will be used to test if the screening is consistent. Relevant articles will be critically appraised by four authors (double checking of 25% of the articles). Quality assessment will focus on selection bias, dating of samples, sample integrity and analytical procedures. Data synthesis will be based on statistical analysis of temporal concentration trends.

Läs mer om What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review protocol

Emissions and fate of brominated flame retardants in the indoor environment: A critical review of modelling approaches

2014. Ioannis Liagkouridis, Ian T. Cousins, Anna Palm Cousins. Science of the Total Environment 491, 87-99

Artikel

This review explores the existing understanding and the available approaches to estimating the emissions and fate of semi-volatile organic compounds (SVOCs) and in particular focuses on the brominated flame retardants (BFRs). Volatilisation, an important emission mechanism for the more volatile compounds can be well described using current emission models. More research is needed, however, to better characterise alternative release mechanisms such as direct material-particle partitioning and material abrasion. These two particle-mediated emissions are likely to result in an increased chemical release from the source than can be accounted for by volatilisation, especially for low volatile compounds, and emission models need to be updated in order to account for these. Air-surface partitioning is an important fate process for SVOCs such as BFRs however it is still not well characterised indoors. In addition, the assumption of an instantaneous air-particle equilibrium adopted by current indoor fate models might not be valid for high-molecular weight, strongly sorbing compounds. A better description of indoor particle dynamics is required to assess the effect of particle-associated transport as this will control the fate of low volatile BFRs. We suggest further research steps that will improve modelling Precision and increase our understanding of the factors that govern the indoor fate of a wide range of SVOCs. It is also considered that the appropriateness of the selected model for a given study relies on the individual characteristics of the study environment and scope of the study.

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Enhanced Elimination of Perfluorooctane Sulfonic Acid by Menstruating Women: Evidence from Population-Based Pharmacokinetic Modeling

2014. Fiona Wong (et al.). Environmental Science and Technology 48 (15), 8807-8814

Artikel

Human biomonitoring studies have shown that concentrations of perfluorooctane sulfonic acid (PFOS) in men are higher than in women. We investigate sex differences in elimination of PFOS by fitting a population-based pharmacokinetic model to six cross-sectional data sets from 1999 to 2012 from the US National Health and Nutrition Examination Survey (NHANES) and derive human first-order elimination rate constants (k(E)) and corresponding elimination half-lives (t(1/2)) for PFOS, where t(1/2) = In 2/k(E). We use a modified version of the Ritter population-based pharmacokinetic model and derive elimination rate constants separately for men and women. The model accounts for population-average lifetime changes in PFOS intake, body weight, and menstruation rate. We compare the model-derived elimination rate constant for hypothetical nonmenstruating women to the elimination rate constant for men and women when menstruation is included as a loss process to evaluate the hypothesis that loss of PFOS by menstruation is an important process for women. The modeled elimination half-life for men is 4.7 years, and the modeled elimination half-life for women when excluding losses from menstruation is 3.7 years. The elimination half-life for women when menstruation is included in the model is 4.0 years. Thus, menstruation accounts for 3096 of the discrepancy in elimination of PFOS between men and women. The remaining discrepancy is likely due to other sex-specific elimination routes that are not considered in our modeling.

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Global emission inventories for C-4-C-14 perfluoroalkyl carboxylic acid (PFCA) homologues from 1951 to 2030, Part I: production and emissions from quantifiable sources

2014. Zhanyun Wang (et al.). Environment International 70, 62-75

Artikel

We quantify global emissions of C-4-C-14 perfluoroalkyl carboxylic acid (PFCA) homologues during the life-cycle of products based on perfluorooctanoic acid (PFOA), perfluorononanoic add (PFNA), perfluorooctane sulfonyl fluoride (POSF), and fluorotelomer compounds. We estimate emissions of 2610-21400 tonnes of C-4-C-14 PFCAs in the period from 1951 to 2015, and project 20-6420 tonnes to be emitted from 2016 to 2030. The global annual emissions steadily increased in the period 1951-2002, followed by a decrease and then another increase in the period 2002-2012. Releases from fluoropolymer production contributed most to historical PFCA emissions (e.g. 55-83% in 1951-2002). Since 2002, there has been a geographical shift of industrial sources (particularly fluoropolymer production sites) from North America, Europe and Japan to emerging Asian economies, especially China Sources differ between PFCA homologues, sometimes Considerably, and the relative contributions of each source change over time. For example, whereas 98-100% of historical (1951-2002) PFOA emissions are attributed to direct releases during the life-cycle of products containing PFOA as ingredients or impurities, a much higher historical contribution from PFCA precursor degradation is estimated for some other homologues (e.g. 9-78% for PFDA). We address the uncertainties of the PFCA emissions by defining a lower and a higher emission scenario, which differ by approximately a factor of eight.

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Global emission inventories for C-4-C-14 perfluoroalkyl carboxylic acid (PFCA) homologues from 1951 to 2030, part II: The remaining pieces of the puzzle

2014. Zhanyun Wang (et al.). Environment International 69, 166-176

Artikel

We identify eleven emission sources of perfluoroalkyl carboxylic adds (PFCAs) that have not been discussed in the past. These sources can be divided into three groups: [i] PFCAs released as ingredients or impurities, e.g., historical and current use of perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA) and their derivatives; [ii] PFCAs formed as degradation products, e.g., atmospheric degradation of some hydrofluorocarbons (HFCs) and hydrofluoroethers (HFEs); and [iii] sources from which PFCAs are released as both impurities and degradation products, e.g., historical and current use of perfluorobutane sulfonyl fluoride (PBSF)- and perfluorohexane sulfonyl fluoride (PHxSF)-based products. Available information confirms that these sources were active in the past or are still active today, but due to a lack of information, it is not yet possible to quantify emissions from these sources. However, our review of the available information on these sources shows that some of the sources may have been significant in the past (e.g., the historical use of PFBA-, PFHxA-, PBSF- and PHxSF-based products), whereas others can be significant in the long-term (e.g., (bio)degradation of various side-chain fluorinated polymers where PFCA precursors are chemically bound to the backbone). In addition, we summarize critical knowledge and data gaps regarding these sources as a basis for future research.

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Helsingor Statement on poly- and perfluorinated alkyl substances (PFASs)

2014. Martin Scheringer (et al.). Chemosphere 114, 337-339

Artikel

In this discussion paper, the transition from long-chain poly- and perfluorinated alkyl substances (PFASs) to fluorinated alternatives is addressed. Long-chain PFASs include perfluoroalkyl carboxylic acids (PFCAs) with 7 or more perfluorinated carbons, perfluoroalkyl sulfonic acids (PFSAs) with 6 or more perfluorinated carbons, and their precursors. Because long-chain PFASs have been found to be persistent, bioaccumulative and toxic, they are being replaced by a wide range of fluorinated alternatives. We summarize key concerns about the potential impacts of fluorinated alternatives on human health and the environment in order to provide concise information for different stakeholders and the public. These concerns include, amongst others, the likelihood of fluorinated alternatives or their transformation products becoming ubiquitously present in the global environment; the need for more information on uses, properties and effects of fluorinated alternatives; the formation of persistent terminal transformation products including PFCAs and PFSAs; increasing environmental and human exposure and potential of adverse effects as a consequence of the high ultimate persistence and increasing usage of fluorinated alternatives; the high societal costs that would be caused if the uses, environmental fate, and adverse effects of fluorinated alternatives had to be investigated by publicly funded research; and the lack of consideration of non-persistent alternatives to long-chain PFASs.

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Identifying Chemicals That Are Planetary Boundary Threats

2014. Matthew MacLeod (et al.). Environmental Science and Technology 48 (19), 11057-11063

Artikel

Rockstrom et al. proposed a set of planetary boundaries that delimit a safe operating space for humanity Many of the planetary boundaries that have so far been identified are determined by chemical agents. Other chemical pollution-related planetary boundaries likely exist, but are currently unknown. A chemical posed an unknown planetary boundary threat if it simultaneously fulfills three conditions (1) it has an unknown disruptive effect on a vital Earth system process; (2) the disruptive effect is not discovered until it is a problem at the global scale, and (3) the effect is not readily reversible. In this paper, we outline scenarios in which chemical could fulfill each of the three conditions, then use the scenarios as the basis to define chemical profiles that fit each scenario. The chemical profiles are defined in terms of the nature of the effect of the chemical and the nature of exposure of the environment to the chemical. Priortization of chemicals in commerce against some of the profiles appears feasible, but there are considerable uncertainites and scientific challenges that must be addressed. Most challenging is prioritizing chemicals for the potential to have a currently unknown effect on a vital. Earth system process. We conclude that the most effective strategy currently available to identify chemicals that are planetary boundary threats is prioritization against profiles defined in terms of environmental exposure combined with monitoring and study of the biogeochemical process that underlie vital Earth system processes to identify currently unknown disruptive effects.

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Modelling the influence of climate change on the chemical concentrations in the Baltic Sea region with the POPCYCLING-Baltic model

2014. Deguo Kong, Matthew MacLeod, Ian T. Cousins. Chemosphere 110, 31-40

Artikel

The effect of projected future changes in temperature, wind speed, precipitation and particulate organic carbon on concentrations of persistent organic chemicals in the Baltic Sea regional environment is evaluated using the POPCYCLING-Baltic multimedia chemical fate model. Steady-state concentrations of hypothetical perfectly persistent chemicals with property combinations that encompass the entire plausible range for non-ionizing organic substances are modelled under two alternative climate change scenarios (IPCC A2 and B2) and compared to a baseline climate scenario. The contributions of individual climate parameters are deduced in model experiments in which only one of the four parameters is changed from the baseline scenario. Of the four selected climate parameters, temperature is the most influential, and wind speed is least. Chemical concentrations in the Baltic region are projected to change by factors of up to 3.0 compared to the baseline climate scenario. For chemicals with property combinations similar to legacy persistent organic pollutants listed by the Stockholm Convention, modelled concentration ratios between two climate change scenarios and the baseline scenario range from factors of 0.5 to 2.0. This study is a first step toward quantitatively assessing climate change-induced changes in the environmental concentrations of persistent organic chemicals in the Baltic Sea region.

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Statistical Analysis of Long-Term Monitoring Data for Persistent Organic Pollutants in the Atmosphere at 20 Monitoring Stations Broadly Indicates Declining Concentrations

2014. Deguo Kong (et al.). Environmental Science and Technology 48 (21), 12492-12499

Artikel

During recent decades concentrations of persistent organic pollutants (POPs) in the atmosphere have been monitored at multiple stations worldwide. We used three statistical methods to analyze a total of 748 time series of selected POPs in the atmosphere to determine if there are statistically significant reductions in levels of POPs that have had control actions enacted to restrict or eliminate manufacture, use and emissions. Significant decreasing trends were identified in 560 (75%) of the 748 time series collected from the Arctic, North America, and Europe, indicating that the atmospheric concentrations of these POPs are generally decreasing, consistent with the overall effectiveness of emission control actions. Statistically significant trends in synthetic time series could be reliably identified with the improved Mann-Kendall (iMK) test and the digital filtration (DF) technique in time series longer than 5 years. The temporal trends of new (or emerging) POPs in the atmosphere are often unclear because time series are too short. A statistical detrending method based on the iMK test was not able to identify abrupt changes in the rates of decline of atmospheric POP concentrations encoded into synthetic time series.

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Temporal trends (1999-2010) of perfluoroalkyl acids in commonly consumed food items

2014. Jana H. Johansson (et al.). Environmental Pollution 188, 102-108

Artikel

The aim of this study was to determine how dietary exposure to PFAAs has changed over the period when major production changes occurred. Archived samples (1999-2010) of eggs, milk and farmed rainbow trout were analyzed by ultra performance liquid chromatography coupled to tandem mass spectrometry. Statistically significant decreasing trends were observed for concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in fish (p < 0.002 and p < 0.032, respectively) and eggs (p < 0.001 for both compounds). Concentrations of PFOS in fish and eggs decreased by a factor of 10 and 40, respectively. In eggs there was also a statistically significant decreasing trend in concentrations of perfluorooctanoic acid (PFOA). The results of this study demonstrate that PFAA concentrations in food items from agricultural food chains and aquatic food chains close to sources respond rapidly to changes in environmental emissions. Implications for the overall understanding of human exposure are discussed.

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Bioaccumulation of perfluoroalkyl acids in dairy cows in a naturally contaminated environment

2013. Robin Vestergren (et al.). Environmental Science and Pollution Research 20 (11), 7959-7969

Artikel

Beef and dairy products may be important vectors of human exposure to perfluoroalkyl acids (PFAAs), but the understanding of how PFAAs are accumulated and transferred through agricultural food chains is very limited. Here, the bioaccumulation of PFAAs in dairy cows receiving naturally contaminated feed and drinking water was investigated by conducting a mass balance of PFAAs for a herd of dairy cows in a barn on a typical Swedish dairy farm. It was assumed that the cows were able to reach steady state with their dietary intake of PFAAs. Perfluorooctane sulfonic acid (PFOS) and perfluoroalkyl carboxylic acids (PFCAs) with 8 to 12 carbons were detected in cow tissue samples (liver, muscle, and blood) at concentrations up to 130 ng kg(-1). Mass balance calculations demonstrated an agreement between total intake and excretion within a factor of 1.5 and consumption of silage was identified as the dominant intake pathway for all PFAAs. Biomagnification factors (BMFs) were highly tissue and homologue specific. While BMFs of PFOS and PFCAs with 9 and 10 fluorinated carbons in liver ranged from 10 to 20, perfluorooctanoic acid (PFOA) was not biomagnified (BMF < 1) in any of the investigated tissues. Biotransfer factors (BTFs; defined as the concentration in tissue divided by the total daily intake) were calculated for muscle and milk. Log BTFs ranged from -1.95 to -1.15 day kg(-1) with the highest BTF observed for PFOS in muscle. Overall, the results of this study suggest that long-chain PFAAs have a relatively high potential for transfer to milk and beef from the diet of dairy cows. However, a low input of PFAAs to terrestrial systems via atmospheric deposition and low bioavailability of PFAAs in soil limits the amount of PFAAs that enter terrestrial agricultural food chains in background contaminated environments and makes this pathway less important than aquatic exposure pathways. The BTFs estimated here provide a useful tool for predicting human exposure to PFAAs via milk and beef under different contamination scenarios.

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Bounding uncertainties in intrinsic human elimination half-lives and intake of polybrominated diphenyl ethers in the North American population

2013. Fiona Wong, Ian T. Cousins, Matthew MacLeod. Environment International 59, 168-174

Artikel

We examine the balance between intake, intrinsic elimination half-lives and human body burdens measured in biomonitoring for polybrominated diphenyl ethers (PBDEs) in the North American population using the population-level pharmacokinetic model developed by Ritter et al. (2011). Empirical data are collected from two studies that made total intake estimates for the North American population for the years 2004 and 2005, and eight biomonitoring studies for the years 1992 to 2009. We assume intake of PBDEs increased exponentially to a peak in 2004, and has since exponentially declined. The model is fitted to the empirical PBDE intake and biomonitoring data on PBDE body burden using a least-square optimization method by adjusting the intake in 2004 and 2038, and the intrinsic elimination rate constants, which can be expressed as equivalent half-lives. We. fit the model in two types of scenarios using different combinations of PBDE intake estimates and biomonitoring data. Our modeling results indicate that there is an inconsistency between the PBDE intake estimates and the biomonitoring data, and that the inconsistency is likely due to underestimation of population-level intake. More efforts are needed to better characterize intake rates and identify potentially-unrecognized exposure pathways. Additional age-stratified biomonitoring data, and time trends of PBDE intakes would better constrain the model and provide an improved estimation of the intrinsic elimination half-lives.

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Confronting Unknown Planetary Boundary Threats from Chemical Pollution

2013. Linn Persson (et al.). Environmental Science and Technology 47 (22), 12619-12622

Artikel

Rockström et al. proposed a set of planetary boundaries that delimitate a “safe operating space for humanity”. One of the planetary boundaries is determined by “chemical pollution”, however no clear definition was provided. Here, we propose that there is no single chemical pollution planetary boundary, but rather that many planetary boundary issues governed by chemical pollution exist. We identify three conditions that must be simultaneously met for chemical pollution to pose a planetary boundary threat. We then discuss approaches to identify chemicals that could fulfill those conditions, and outline a proactive hazard identification strategy that considers long-range transport and the reversibility of chemical pollution.

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Effects of input uncertainty and variability on the modelled environmental fate of organic pollutants under global climate change scenarios

2013. Deguo Kong (et al.). Chemosphere 93 (9), 2086-2093

Artikel

Global climate change (GCC) is expected to influence the fate, exposure and risks of organic pollutants to wildlife and humans. Multimedia chemical fate models have been previously applied to estimate how GCC affects pollutant concentrations in the environment and biota, but previous studies have not addressed how uncertainty and variability of model inputs affect model predictions. Here, we assess the influence of climate variability and chemical property uncertainty on future projections of environmental fate of six polychlorinated biphenyl congeners under different GCC scenarios using a spreadsheet version of the ChemCAN model and the Crystal Ball® software. Regardless of emission mode, results demonstrate: (i) uncertainty in degradation half-lives dominates the variance of modelled absolute levels of PCB congeners under GCC scenarios; (ii) when the ratios of predictions under GCC to predictions under present day climate are modelled, climate variability dominates the variance of modelled ratios; and (iii) the ratios also indicate a maximum of about a factor of 2 change in the long-term average environmental concentrations due to GCC that is forecasted between present conditions and the period between 2080 and 2099. We conclude that chemical property uncertainty does not preclude assessing relative changes in a GCC scenario compared to a present-day scenario if variance in model outputs due to chemical properties and degradation half-lives can be assumed to cancel out in the two scenarios.

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Estimation of the Acid Dissociation Constant of Perfluoroalkyl Carboxylic Acids through an Experimental Investigation of their Water-to-Air Transport

2013. Lena Vierke, Urs Berger, Ian T. Cousins. Environmental Science and Technology 47 (19), 11032-11039

Artikel

The acid dissociation constants (pK(a)s) of perfluoroalkyl carboxylic acids (PFCAs) have been the subject of discussion in the literature; for example, values from -0.2 to 3.8 have been suggested for perfluorooctanoic acid (PFOA). The dissociated anionic conjugate bases of PFCAs have negligible air-water partition coefficients (K(AW)s) and do not volatilize from water. The neutral acids, however, have relatively high K(AW)s and volatilization from water has been demonstrated. The extent of volatilization of PFCAs in the environment will depend on the water pH and their pK(a). Knowledge of the pK(a)s of PFCAs is therefore vital for,understanding their environmental transport and fate. We investigated the water-to-air transfer of PFCAs in a novel experimental setup. We used similar to 1 mu g L-1 of PFCAs in water (above environmental background concentrations but below the concentration at which self-association occurs) at different water pH (pH 0.3 to pH 6.9) and sampled the PFCAs volatilized from water during a 2-day experiment. Our results suggest that the pK(a)s of C4-11 PFCAs are <1.6. For PFOA, we derived a pK(a) of 0.5 from fitting the experimental measurements with a volatilization model. Perfluoroalkane sulfonic acids were not volatilized, suggesting that their pK(a)s are below the investigated pH range (pK(a) <0.3).

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Fluorinated alternatives to long-chain perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkane sulfonic acids (PFSAs) and their potential precursors

2013. Zhanyun Wang (et al.). Environment International 60, 242-248

Artikel

Since 2000 there has been an on-going industrial transition to replace long-chain perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkane sulfonic adds (PFSAs) and their precursors. To date, information on these replacements including their chemical identities, however, has not been published or made easily accessible to the public, hampering risk assessment and management of these chemicals. Here we review information on fluorinated alternatives in the public domain. We identify over 20 fluorinated substances that are applied in [i] fluoropolymer manufacture, [ii] surface treatment of textile, leather and carpets, [iii] surface treatment of food contact materials, [iv] metal plating, [v] fire-fighting foams, and [vi] other commercial and consumer products. We summarize current knowledge on their environmental releases, persistence, and exposure of biota and humans. Based on the limited information available, it is unclear whether fluorinated alternatives are safe for humans and the environment. We identify three major data gaps that must be filled to perform meaningful risk assessments and recommend generation of the missing data through cooperation among all stakeholders (industry, regulators, academic scientists and the public).

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Human dietary exposure to per- and poly-fluoroalkyl substances (PFASs)

2013. Robin Vestergren, Ian T. Cousins. Persistent organic pollutants and toxic metals in foods, 279-307

Kapitel

Per- and polyfluoroalkyl substances (PFASs) are a class of emerging contaminants with numerous industrial and commercial applications. Within this class the best studied substances are the perfluoroalkane sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs). PFSAs and PFCAs have been detected in human serum samples from all around the world and are ubiquitous in the global environment and wildlife. As well as being completely resistant to environmental degradation, some PFSAs and PFCAs are bioaccumulative and potentially toxic, which raises a concern about population-wide exposure to this group of substances. Dietary intake has been suggested as a major pathway of human exposure to the two most widely studied substances among PFSAs and PFCAs, namely perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, the difficulties associated with the analysis of PFSAs, PFCAs and related PFASs at ultra-trace levels in food samples have hampered the understanding of human exposure. Recent advances in analytical chemistry have dramatically improved the ability to measure these substances and other PFASs in food matrices, and method detection limits down to low picogram per gram food can now be reached. Worldwide interlaboratory studies also indicate that the accuracy and precision of analytical methods have significantly improved over the last decade. These modern methods have been applied to quantify human dietary exposure to PFCAs and PFSAs in several European countries. Overall, the exposure to PFOS and PFOA from diet is typically a factor of 6 to 10 higher than the exposure from other known exposure pathways for the general adult population of Western countries. Furthermore, application of toxicokinetic models indicates that present day serum concentrations of PFOS and PFOA can largely be explained by the estimated dietary exposures. Despite the recent advances in analytical techniques, the sources of food contamination are not very well characterized. It has been demonstrated that bioaccumulation and biomagnification in aquatic food webs is a primary transfer mechanism for PFOS and several long-chain perfluoroalkyl carboxylic acids to the human diet. However, more research is needed to understand the accumulation of PFASs in terrestrial food webs and the transfer of a range of PFASs from food-contact materials.

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Influence of global climate change on chemical fate and bioaccumulation: The role of multimedia models

2013. Todd Gouin (et al.). Environmental Toxicology and Chemistry 32 (1), 20-31

Artikel

Multimedia environmental fate models are valuable tools for investigating potential changes associated with global climate change, particularly because thermodynamic forcing on partitioning behavior as well as diffusive and nondiffusive exchange processes are implicitly considered. Similarly, food-web bioaccumulation models are capable of integrating the net effect of changes associated with factors such as temperature, growth rates, feeding preferences, and partitioning behavior on bioaccumulation potential. For the climate change scenarios considered in the present study, such tools indicate that alterations to exposure concentrations are typically within a factor of 2 of the baseline output. Based on an appreciation for the uncertainty in model parameters and baseline output, the authors recommend caution when interpreting or speculating on the relative importance of global climate change with respect to how changes caused by it will influence chemical fate and bioavailability.

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Persistence, Bioaccumulation, and Toxicity of Halogen-Free Flame Retardants

2013. Susanne L. Waaijers (et al.). Reviews of Environmental Contamination and Toxicology, 1-71

Kapitel

Polymers are synthetic organic materials having a high carbon and hydrogen content, which make them readily combustible. Polymers have many indoor uses and their flammability makes them a fire hazard. Therefore, flame retardants (FRs) are incorporated into these materials as a safety measure. Brominated flame retardants (BFRs), which accounted for about 21% of the total world market of FRs, have several unintended negative effects on the environment and human health. Hence, there is growing interest in finding appropriate alternative halogen-free flame retardants (HFFRs). Many of these HFFRs are marketed already, although their environ- mental behavior and toxicological properties are often only known to a limited extent, and their potential impact on the environment cannot yet be properly assessed. Therefore, we undertook this review to make an inventory of the available data that exists (up to September 2011) on the physical-chemical properties, pro- duction volumes, persistence, bioaccumulation, and toxicity (PBT) of a selection of HFFRs that are potential replacements for BFRs in polymers. Large data gaps were identified for the physical-chemical and the PBT properties of the reviewed HFFRs. Because these HFFRs are currently on the market, there is an urgent need to fill these data gaps. Enhanced transparency of methodology and data are needed to reevaluate certain test results that appear contradictory, and, if this does not provide new insights, further research should be performed. TPP has been studied quite extensively and it is clearly persistent, bioaccumulative, and toxic. So far, RDP and BDP have demonstrated low to high ecotoxicity and persistence. The compounds ATH and ZB exerted high toxicity to some species and ALPI appeared to be persistent and has low to moderate reported ecotoxicity. DOPO and MPP may be persistent, but this view is based merely on one or two studies, clearly indicating a lack of information. Many degradation studies have been performed on PER and show low persistence, with a few exceptions. Additionally, there is too l ittle information on the bioaccumulation potential of PER. APP mostly has low PBT properties; however, moderate ecotoxicity was reported in two studies. Mg(OH)₂, ZHS, and ZS do not show such remarkably high bioaccumulation or toxicity, but large data gaps exist for these compounds also. Nevertheless, we consider the latter compounds to be the most promising among alternative HFFRs. To assess whether the presently reviewed HFFRs are truly suitable alternatives, each compound should be examined individually by comparing its PBT values with those of the relevant halogenated flame retardant. Until more data are available, it remains impossible to accurately evaluate the risk of each of these compounds, including the ones that are already extensively marketed.

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Temporal trends in dioxins (polychlorinated dibenzo-p-dioxin and dibenzofurans) and dioxin-like polychlorinated biphenyls in Baltic herring (Clupea harengus)

2013. Aroha Miller (et al.). Marine Pollution Bulletin 73 (1), 220-230

Artikel

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) concentrations in Baltic herring (Clupea harengus) have been relatively stable since the mid to late 1990s. It is unclear why concentrations in Baltic herring are not following the observed decreases in other environmental matrices. Here, changes in long-term temporal trends in Baltic herring were examined. A number of biological variables were examined alongside the temporal trends to investigate whether fish biology e.g., growth (length, weight, age), lipid content, reproductive phase or fishing date may provide an explanation for the temporal trends observed. Significant (p < 0.05) decreasing trends were observed for PCDD/F toxic equivalents (TEQ(PCDD/F)) at three of the four sites (lipid weight (lw) and wet weight (ww), Swedish west coast lw only); however, other TEQ values e.g., TEQ(PCDD), TEQ(PCDF), TEQ(dl-PCB), TEQ(PCDD/F+dl-PCB) were inconsistent, decreasing at some sites but not others. In the most recent 10 years of data, fewer significant decreases were seen overall. Over the examined time period, significant decreases (Bothnian Bay, p < 0.01, southern Baltic Proper, p < 0.02) and increases (Swedish west coast, p < 0.02) in lipid content, growth dilution or lack thereof, and significant changes in age were observed. However herring were not randomly selected which biases this result. Continual efforts to decrease PCDD/F and dl-PCB emissions and to locate/reduce hotspots are necessary, while bearing in mind that herring biology may be impeding faster decreases of these chemicals.

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A matrix effect-free method for reliable quantification of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids at low parts per trillion levels in dietary samples

2012. Robin Vestergren (et al.). Journal of Chromatography A 1237, 64-71

Artikel

In recent exposure modeling studies diet has been identified as the dominant pathway of human exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, the paucity of highly sensitive and accurate analytical data to support these studies means that their conclusions are open to question. Here a novel matrix effect-free method is described for ultra-trace analysis of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids in dietary samples of varied composition. The method employs ion pair extraction of the analytes into methyl tert-butyl ether and subsequent solid phase extraction clean-up on Florisil and graphitized carbon. The target compounds are separated and detected using ultra performance liquid chromatography coupled to tandem mass spectrometry. Special care was taken to avoid procedural blank contamination and potential contamination sources were elucidated. The performance of the method was validated for five different food test matrices including a duplicate diet sample. Method detection limits in the low to sub pg g(-1) range were obtained for all target analytes, which is 5-100 times more sensitive than previously reported for duplicate diet samples. Total method recoveries were consistently between 50 and 80% for all analytes in all tested food matrices and effects of co-extracted matrix constituents on ionization of the target compounds were found to be negligible. The precision of the method (defined as percentage relative standard deviation) at concentrations close to the respective method limits of quantification was <15% for all analytes. Accurate quantification at ultra-trace levels was demonstrated by laboratory control spike experiments. For the first time the presence of long-chain PFCAs in duplicate diet samples is reported. The method presented here can thus support an improved assessment of human exposure from dietary intake for a range of PFCA and PFSA homologues. Re-analysis of duplicate diet samples, which had been analyzed earlier using another analytical methodology, indicated that dietary intake of PFOA and PFOS may previously have been overestimated.

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Assessing the Relative Importance of Spatial Variability in Emissions Versus Landscape Properties in Fate Models for Environmental Exposure Assessment of Chemicals

2012. A. Hollander (et al.). Environmental Modelling and Assessment 17 (6), 577-587

Artikel

Multimedia mass balance models differ in their treatment of spatial resolution from single boxes representing an entire region to multiple interconnected boxes with varying landscape properties and emission intensities. Here, model experiments were conducted to determine the relative importance of these two main factors that cause spatial variation in environmental chemical concentrations: spatial patterns in emission intensities and spatial differences in environmental conditions. In the model, experiments emissions were always to the air compartment. It was concluded that variation in emissions is in most cases the dominant source of variation in environmental concentrations. It was found, however, that variability in environmental conditions can strongly influence predicted concentrations in some cases, if the receptor compartments of interest are soil or water-for water concentrations particularly if a chemical has a high octanol-air partition coefficient (K-oa). This information will help to determine the required level of spatial detail that suffices for a specific regulatory purpose.

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Tracing the origin of dioxins in Baltic air using an atmospheric modeling approach

2012. Victor Shatalov (et al.). Atmospheric Pollution Research 3 (4), 408-416

Artikel

Previous work has concluded that the sources of dioxins to the Baltic Sea are dominated by atmospheric deposition. Here, we investigate whether current emission estimates can explain Baltic air levels and deposition fluxes of four selected 2,3,7,8-substituted PCDD/F congeners using an atmospheric modeling approach. The EMEP (European Monitoring and Evaluation Programme) database of emissions for dioxins was used to provide inputs to the selected model (MSCE-POP model) and model predicted levels were compared with measurements of dioxins in air and deposition fluxes at three monitoring stations in Sweden. The model underestimated air concentrations between a factor of 5 and 30, with the level of agreement depending on congener, monitoring station and, importantly, with the compass sector from which the contaminated air mass had arrived. Additional model simulations were undertaken in which emissions were enlarged in some selected areas to optimize agreement between model predictions and measurements. A novel emission adjustment approach is used in an attempt to identify source regions where emissions were in error. The emission adjustment approach improved the agreement between model predictions and measurements for 60% of the measurements within a factor of 3 of model predicted concentrations. However, the agreement was still relatively poor when air masses originated from the SSE and SSW. The model adjustment procedure gives an indication of the magnitude of error in exiting emission estimates, but due to the poor quality of existing emission databases and few quality air monitoring data it is not currently possible to use the emission adjustment approach to accurately identify source regions of error. The approach presented here is promising, however, and could be applied to other substances where better emission and monitoring data are available. (C) Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License.

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Development of a dynamic model for estimating the food web transfer of chemicals in small aquatic ecosystems

2011. Erick Nfon, James M. Armitage, Ian T. Cousins. Science of the Total Environment 409 (24), 5416-5422

Artikel

A dynamic combined fate and food web model was developed to estimate the food web transfer of chemicals in small aquatic ecosystems (i.e. ponds). A novel feature of the modeling approach is that aquatic macrophytes (submerged aquatic vegetation) were included in the fate model and were also a food item in the food web model. The paper aims to investigate whether macrophytes are effective at mitigating chemical exposure and to compare the modeling approach developed here with previous modeling approaches recommended in the European Union (EU) guideline for risk assessment of pesticides. The model was used to estimate bioaccumulation of three hypothetical chemicals of varying hydrophobicity in a pond food web comprising 11 species. Three different macrophyte biomass densities were simulated in the model experiments to determine the influence of macrophytes on fate and bioaccumulation. Macrophytes were shown to have a significant effect on the fate and food web transfer of highly hydrophobic compounds with log K(ow)> = 5. Modeled peak concentrations in biota were highest for the scenarios with the lowest macrophyte biomass density. The distribution and food web transfer of the hypothetical compound with the lowest hydrophobicity (log K(ow) = 3) was not affected by the inclusion of aquatic macrophytes in the pond environment. For the three different hypothetical chemicals and at all macrophyte biomass densities, the maximum predicted concentrations in the top predator in the food web model were at least one order of magnitude lower than the values estimated using methods suggested in EU guidelines. The EU guideline thus provides a highly conservative estimate of risk. In our opinion, and subject to further model evaluation, a realistic assessment of dynamic food web transfer and risk can be obtained using the model presented here.

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Reconciling measurement and modelling studies of the sources and fate of perfluorinated carboxylates

2011. Ian Cousins, Deguo Kong, Robin Vestergren. Environmental Chemistry 8 (4), 339-354

Artikel

This study critically evaluates the recently published measurement and modelling studies of the sources and fate of perfluorinated carboxylates (PFCAs). It is concluded that modelling studies provide support to the 'direct hypothesis' for PFOA and PFNA (i.e. the global dominance of direct sources (mainly from fluoropolymer manufacturing)). Empirical evidence for the importance of direct sources of PFOA and PFNA is provided by PFNA : PFOA ratios and isomer profiles of PFOA in ocean water. However, homologue patterns of long-chain PFCAs in biota from remote regions suggest that indirect sources (mainly from precursor degradation) are proportionally more important for PFCAs with more than 10 carbons. Temporal data in biotic and abiotic media are reviewed and an increasing trend to 2000 is observed for all PFCAs, with discrepancies in time trends reported after that period. Some studies on temporal patterns report a levelling off or decline in the latter part of the 2000s for PFOA and PFNA, whereas others show a continual increase throughout the study period. Differences in temporal patterns result from the fact that some environments respond faster to emission changes than others and may thus be useful to elucidate the importance of direct and indirect sources to different regions.

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Toward a Consistent Evaluative Framework for POP Risk Characterization

2011. Jon A. Arnot (et al.). Environmental Science and Technology 45 (1), 97-103

Artikel

The purpose of Annex E in the Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) is to assess whether a chemical is likely, as a result of its long-range environmental transport, to lead to significant adverse human health or environmental effects, such that global action is warranted. To date, risk profiles for nominated POPs have not consistently selected assessment endpoints or completed mandated risk characterizations. An assessment endpoint hierarchy is proposed to facilitate risk characterization for the implementation of the SC. The framework is illustrated for a nominated POP, hexabromocyclododecane (HBCD), using three risk estimation methods. Based on current monitoring and toxicity data, the screening-level results indicate that humans and ecological receptors in remote regions such as the Arctic are unlikely to experience significant adverse effects (i.e., low risk) due to long-range environmental transport of HBCD. The results for birds are more uncertain than the results for fish and mammals due to the paucity of avian toxicity data. Risk characterization results for HBCD and for some listed POPs are compared to illustrate how the proposed methods can further assist decision-making and chemical management.

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Using COSMOtherm to predict physicochemical properties of poly- and perfluorinated alkyl substances (PFASs)

2011. Zhanyun Wang (et al.). Environmental Chemistry 8 (4), 389-398

Artikel

Recently, there has been concern about the presence of poly- and perfluorinated alkyl substances (PFASs) in the environment, biota and humans. However, lack of physicochemical data has limited the application of environmental fate models to understand the environmental distribution and ultimate fate of PFASs. We employ the COSMOtherm model to estimate physicochemical properties for 130 individual PFASs, namely perfluoroalkyl acids (including branched isomers for C(4)-C(8) perfluorocarboxylic acids), their precursors and some important intermediates. The estimated physicochemical properties are interpreted using structure-property relationships and rationalised with insight into molecular interactions. Within a homologous series of linear PFASs with the same functional group, both air-water and octanol-water partition coefficient increase with increasing perfluorinated chain length, likely due to increasing molecular volume. For PFASs with the same perfluorinated chain length but different functional groups, the ability of the functional group to form hydrogen bonds strongly influences the chemicals' partitioning behaviour. The partitioning behaviour of all theoretically possible branched isomers can vary considerably; however, the predominant isopropyl and monomethyl branched isomers in technical mixtures have similar properties as their linear counterparts (differences below 0.5 log units). Our property estimates provide a basis for further environmental modelling, but with some caveats and limitations.

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Water-to-air transfer of perfluorinated carboxylates and sulfonates in a sea spray simulator

2011. Margot Reth (et al.). Environmental Chemistry 8 (4), 381-388

Artikel

One hypothesis for the origin of perfluorinated alkyl acids, their salts and conjugate bases (here collectively termed PFAAs) in the atmosphere is transfer from the surface ocean by sea spray, the mechanistic explanation being that the surface active properties of PFAAs result in their enrichment on the surface of bursting bubbles. The water-to-air transfer of C(6)-C(14) perfluorocarboxylates (PFCAs) and C(6), C(8) and C(10) perfluorosulfonates (PFSAs) was studied in a laboratory scale sea spray simulator containing tap water spiked with PFCAs and PFSAs. The sequestration of the PFAAs out of bulk water and to the air-water surface was shown to increase exponentially with the length of the perfluorinated alkyl chain. Volatilisation of the PFAAs from an aqueous solution in the absence of spray resulted in less than 1% transfer to the atmosphere during the experiment. In the presence of spray the transfer rate from water to air increased by up to 1360 times. The enhancement was dependent on the PFAA chain length, with the C(6) carboxylate showing an enhancement of a factor of 37, the C(7) carboxylate an enhancement of 320, whereas for all remaining PFAAs the enhancement exceeded 450 with the exception of the C(14) carboxylate (106).

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Additions and corrections to “Modeling the global fate and transport of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources using a multispecies mass balance model”

2009. James M Armitage, Matthew Macleod, Ian T Cousins.

Övrigt

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Comparative Assessment of the Global Fate and Transport Pathways of Long-chain Perfluorocarboxylic Acids (PFCAs) and Perfluorocarboxylates (PFCs) Emitted from Direct Sources

2009. James M Armitage, Matthew Macleod, Ian T Cousins. Environmental Science and Technology 43 (15), 5830-5836

Artikel

A global-scale multispecies mass balance model was used to simulate the long-term fate and transport of perfluorocarboxylic acids (PFCAs) with eight to thirteen carbons (C8−C13) and their conjugate bases, the perfluorocarboxylates (PFCs). The main purpose of this study was to assess the relative long-range transport (LRT) potential of each conjugate pair, collectively termed PFC(A)s, considering emissions from direct sources (i.e., manufacturing and use) only. Overall LRT potential (atmospheric + oceanic) varied as a function of chain length and depended on assumptions regarding pK_a and mode of entry. Atmospheric transport makes a relatively higher contribution to overall LRT potential for PFC(A)s with longer chain length, which reflects the increasing trend in the air−water partition coefficient (K_AW) of the neutral PFCA species with chain length. Model scenarios using estimated direct emissions of the C8, C9, and C11 PFC(A)s indicate that the mass fluxes to the Arctic marine environment associated with oceanic transport are in excess of mass fluxes from indirect sources (i.e., atmospheric transport of precursor substances such as fluorotelomer alcohols and subsequent degradation to PFCAs). Modeled concentrations of C8 and C9 in the abiotic environment are broadly consistent with available monitoring data in surface ocean waters. Furthermore, the modeled concentration ratios of C8 to C9 are reconcilable with the homologue pattern frequently observed in biota, assuming a positive correlation between bioaccumulation potential and chain length. Modeled concentration ratios of C11 to C10 are more difficult to reconcile with monitoring data in both source and remote regions. Our model results for C11 and C10 therefore imply that either (i) indirect sources are dominant or (ii) estimates of direct emission are not accurate for these homologues.

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Influence of submerged aquatic vegetation on the fate and food web transfer of pesticides in small freshwater ecosystems

2009. Erick Nfon, James Armitage, Ian Cousins. Chemosphere

Artikel

A dynamic combined fate and food web model was developed to investigate the influence of macrophytes (submerged aquatic vegetation) on the fate and food web transfer of pesticides of varying chemical properties in small-scale ecosystems such as ponds, streams, ditches or mesocosms. The model results indicate that aquatic macrophytes have a significant effect on the fate and food web transfer of highly hydrophobic compounds with log K_OW ≥ 5. Modelled peak concentrations in biota were highest for the scenarios assuming the lowest macrophytes biomass density. The distribution and food web transfer of compounds with log K_OW ≤ 4, which is a more representative hydrophobicity of the majority of current-use pesticides, are not affected by the inclusion of aquatic macrophytes in the pond environment. The increased importance of macrophytes for the highly hydrophobic compounds is a result of the dominance of particle deposition in the mass transfer of organic compounds from water to macrophytes. It is recommended that the mechanistic model developed here be used as a tool for interpreting laboratory, mesocosm and field measurements as well as a possible higher-tier regulatory tool, especially for assessing the aquatic behaviour of pesticides with high K_OW values.

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Modeling the Global Fate and Transport of Perfluorooctane Sulfonate (PFOS) and Precursor Compounds in Relation to Temporal Trends in Wildlife Exposure.

2009. James M Armitage (et al.). Environmental Science and Technology 43 (24), 9274-80

Artikel

A global-scale fate and transport model was applied to investigate the historic and future trends in ambient concentrations of perfluorooctane sulfonate (PFOS) and volatile perfluorooctane sulfonyl fluoride (POSF)-based precursor compounds in the environment. First, a global emission inventory for PFOS and its precursor compounds was estimated for the period 1957-2010. We used this inventory as input to a global-scale contaminant fate model and compared modeled concentrations with field data. The main focus of the simulations was to examine how modeled concentrations of PFOS and volatile precursor compounds respond to the major production phase-out that occurred in 2000-2002. Modeled concentrations of PFOS in surface ocean waters are generally within a factor of 5 of field data and are dominated by direct emissions of this substance. In contrast, modeled concentrations of the precursor compounds considered in this study are lower than measured concentrations both before and after the production phase-out. Modeled surface ocean water concentrations of PFOS in source regions decline slowly in response to the production phase-out while concentrations in remote regions continue to increase until 2030. In contrast, modeled concentrations of precursor compounds in both the atmosphere and surface ocean water compartment in all regions respond rapidly to the production phase-out (i.e., decline quickly to much lower levels). With respect to wildlife biomonitoring data, since precursor compounds are bioavailable and degrade to PFOS in vivo, it is at least plausible that declining trends in PFOS body burdens observed in some marine organisms are attributable to this exposure pathway. The continued increases in PFOS body burdens observed in marine organisms inhabiting other regions may reflect exposure primarily to PFOS itself, present in the environment due to production and use of this compound as well as degradation of precursor compounds.

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Modeling the Global Fate and Transport of Perfluorooctanoic Acid (PFOA) and Perfluorooctanoate (PFO) Emitted from Direct Sources Using a Multispecies Mass Balance Model

2009. James M Armitage, Michael McLachlan, Ian T Cousins. Environmental Science and Technology 43 (4), 1134-1140

Artikel

The global-scale fate and transport processes of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources were simulated using a multispecies mass balance model over the period 1950 to 2010. The main goal of this study was to assess the atmospheric and oceanic long-range transport potential of direct source emissions and the implications for the contamination of terrestrial and marine systems worldwide. Consistent with previous modeling studies, ocean transport was found to be the dominant pathway for delivering PFO(A) associated with direct sources to the Arctic marine environment, regardless of model assumptions. The modeled concentrations for surface ocean waters were insensitive to assumptions regarding physical−chemical properties and emission mode of entry and were in reasonable agreement with available monitoring data from the Northern Hemisphere. In contrast, model outputs characterizing atmospheric transport potential were highly sensitive to model assumptions, especially the assumed value of the acid dissociation constant (pK_a). However, the complete range of model results for scenarios with different assumptions about partitioning and emissions provide evidence that the atmospheric transport of directly emitted PFO(A) can deliver this substance to terrestrial environments distant from sources. Additional studies in remote or isolated terrestrial systems may provide further insight into the scale of contamination actually attributable to direct sources.

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Tracking the pathways of human exposure to perfluorocarboxylates

2009. Robin Vestergren, Ian T Cousins. Environmental Science and Technology 43 (15), 5565-75

Artikel

Recent analyses of perfluorooctanoate (PFOA) in human blood sera show that the background-exposed population in industrialized countries worldwide exhibits a narrow concentration range; arithmetic means of published studies range between 2 and 8 microg/L PFOA, with the exception of a few outlier studies. The globally comparable human serum concentrations of PFOA and characteristic dominance of PFOA with respect to other perfluorocarboxylate (PFCA) homologues indicate that exposure pathways of humans differ from those of wildlife, where perfluorononanoate (PFNA) is often the dominant homologue. The observed correlations between perfluorooctane sulfonate (PFOS) and PFOA in human serum together with a simultaneous downward time trend of these compounds in human blood sera and blood spots from the year 2000 onward indicate a connection between historical perfluorooctanesulfonyl (POSF) production (phased out by the major manufacturer in 2000-2002) and exposure to both PFOS and PFOA. A comparison of estimated daily intakes to humans based on samples from exposure media (collected post 2000) indicates that food intake is the major contemporary exposure pathway for the background population, whereas drinking water exposure is dominant for populations near sources of contaminated drinking water. A one-compartment pharmacokinetic model used to back-calculate daily intakes from serum levels is shown to provide agreement within a factor of 1.5-5.5 of the daily intakes derived from exposure media, which provides further supporting evidence that dietary exposure is a major ongoing exposure pathway of PFOA to the background population.

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Trophodynamics of mercury and other trace elements in a pelagic food chain from the Baltic Sea

2009. Erick Nfon (et al.). Science of the Total Environment 407 (24), 6267-74

Artikel

Mercury (Hg) and 13 other trace elements (Al, Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) were measured in phytoplankton, zooplankton, mysis and herring in order to examine the trophodynamics in a well-studied pelagic food chain in the Baltic Sea. The fractionation of nitrogen isotopes (delta(15)N) was used to evaluate food web structure and to estimate the extent of trophic biomagnification of the various trace elements. Trophic magnification factors (TMFs) for each trace element were determined from the slope of the regression between trace element concentrations and delta(15)N. Calculated TMFs showed fundamental differences in the trophodynamics of the trace elements in the pelagic food chain studied. Concentrations of Al, Fe, Ni, Zn, Pb and Cd showed statistically significant decreases (TMF<1) with increasing trophic levels and thus these trace elements tropically dilute or biodilute in this Baltic food chain. Cu, As, Cr, Mn, V, Ti and Co showed no significant relationships with trophic levels. Hg was unique among the trace elements studied in demonstrating a statistically significant increase (TMF>1) in concentration with trophic level i.e. Hg biomagnifies in this Baltic food chain. The estimated TMF for Hg in this food chain was comparable to TMFs observed elsewhere for diverse food chains and locations.

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Biomagnification of organic pollutants in benthic and pelagic marine food chains from the Baltic Sea

2008. Erick Nfon, Ian T. Cousins, Dag Broman. Science of the Total Environment 397 (1-3), 190-204

Artikel

The trophic transfer of organic pollutants with varying physical chemical properties was determined in both a pelagic and benthic food chain using delta N-15 as a continuous variable for assessing trophic levels. The trophic transfer of organic pollutants through the entire food chain in terms of food chain magnification factors (FCMFs) was quantified from the slope of the regression between In [concentration] and delta N-15. Organic pollutants with statistically significant FCMFs >1 were considered to biomagnify within the food chain, whereas those with FCMFs < 1 were considered to trophically dilute. Statistically significant FCMFs >1 were found for PCB congeners and organochlorine pesticides in the Baltic food chains whereas statistically significant FCMFs <1 were found for PAHs and PCNs due to trophic dilution resulting from metabolism. FCMFs were generally greater in the pelagic food chain than in the benthic food chain. However, estimated FCMFs for the benthic food chain are likely in error, as the delta N-15 method suggested a food chain structure which was not consistent with the known dietary patterns of the species. Biomagnification factors (BMFs) were additionally calculated as the ratio of the lipid normalized concentrations in the predator and prey species with adjustment for trophic level and were generally consistent with the FCMFs with BMF >1 for PCBs and organochlorines.

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Black Carbon-Inclusive Modeling Approaches for Estimating the Aquatic Fate of Dibenzo-p-dioxins and Dibenzofurans

2008. J Armitage (et al.). Environ. Sci. Technol. 42, 3697-3703

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Black carbon-dominated PCDD/Fs sorption to soils at a former wood impregnation site

2008. G Cornelissen (et al.). Chemosphere 72, 1455-1461

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Considering the role of precursor compounds in consumer exposure to PFOS and PFOA

2008. R Vestergren (et al.). Fluorinated Surfactants New Developments: 1st International Workshop

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Considering the role of precursor compounds in consumer exposure to PFOS and PFOA

2008. R Vestergren (et al.). Dioxin 2008

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Considering the role of precursor compounds in consumer exposure to PFOS and PFOA

2008. R Vestergren (et al.). Organohalogen Compd. 70, 1442-1466

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Contribution of Volatile Precursor Substances to the Flux of Perfluorooctanoate to the Arctic

2008. U. Schenker (et al.). Environ. Sci. Technol. 42, 3710-3716

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Development of a black carbon-inclusive multi-media model: Application for PAHs in Stockholm.

2008. K. Prevedouros (et al.). Chemosphere 70, 607-615

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Estimating Consumer Exposure to PFOS and PFOA

2008. D. Trudel (et al.). Organohalogen Compd. 70, 726-729

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Estimating Consumer Exposure to PFOS and PFOA.

2008. D. Trudel (et al.). Risk Analysis 28 (2), 251-269

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Estimating Consumer Exposure to PFOS and PFOA.

2008. D. Trudel (et al.). Dioxin 2008

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Estimating the contribution of precursor compounds in consumer exposure to PFOS and PFOA

2008. Robin Vestergren (et al.). Chemosphere 73 (10), 1617-1624

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The exposure of humans to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) was quantified with emphasis on assessing the relative importance of metabolic transformation of precursor compounds. A Scenario-Based Risk Assessment (SceBRA) approach was used to model the exposure to these compounds from a variety of different pathways, the uptake into the human body and resulting daily doses. To capture the physiological and behavioral differences of age and gender, the exposure and resulting doses for seven consumer groups were calculated. The estimated chronic doses of a general population of an industrialized country range from 3.9 to 520 ng/(kg day) and 0.3 to 140 ng/(kg day) for PFOS and PFOA, respectively. The relative importance of precursor-based doses of PFOS and PFOA was estimated to be 2–5% and 2–8% in an intermediate scenario and 60–80% and 28–55% in a high-exposure scenario. This indicates that sub groups of the population may receive a substantial part of the PFOS and PFOA doses from precursor compounds, even though they are of low importance for the general population. Similar to a preceding study, uptake of perfluorinated acids from contaminated food and drinking water was identified as the most important pathway of exposure for the general population. The biotransformation yields of telomer-based precursors and to a lesser extent perfluorooctanesulfonylfluoride-based precursors were identified as influential parameters in the uncertainty analysis. Fast food consumption and fraction of food packaging paper treated with PFCs were influential parameters for determining the doses of PFOA.

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Estimating the contribution of precursor compounds in consumer exposure to PFOS and PFOA

2008. R Vestergren (et al.). Chemosphere 73, 1617-1624

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Human Exposure to Perfluorinated Compounds

2008. R Vestergren, I Cousins. Naturvårdsverket

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Model and input uncertainty in multi-media fate modeling: Benzo[α]pyrene concentrations in Europe

2008. M. Hauck (et al.). Chemosphere 72, 959-967

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Modeling the Effects and Uncertainties of Contaminated Sediment Remediation Scenarios in a Norwegian Fjord by Markov Chain Monte Carlo Simulation

2008. T.M. Saloranta (et al.). Environ. Sci. Technol. 42, 200-206

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Läs mer om Modeling the Effects and Uncertainties of Contaminated Sediment Remediation Scenarios in a Norwegian Fjord by Markov Chain Monte Carlo Simulation

Modeling the Potential Influence of Particle Deposition on the Accumulation of Organic Contaminants by Submerged Aquatic Vegetation

2008. J Armitage (et al.). Environ. Sci. Technol. 42, 4052-4059

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Modelling the long-term fate and transport of PFO(A) emitted from direct sources using a two-dimensional global-scale model

2008. J Armitage, I Cousins, M. MacLeod. Organohalogen Compd. 70, 1438-1441

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Modelling the long-term fate and transport of PFO(A) emitted from direct sources using a two-dimensional global-scale model

2008. J Armitage, I Cousins, M. MacLeod. Dioxin 2008

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Overview of Research on Perfluorinated Compounds at ITM

2008. I Cousins, U Berger. Naturvårdsverket

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Comparison and analysis of different approaches for estimating the human exposure to phthalate esters

2007. A. Franco (et al.). Environ. Internat. 33, 283-291

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Empirical evaluation of spatial and non-spatial European-scale multimedia fate models: Results and implications for chemical risk assessment.

2007. James Armitage (et al.). J. Environ. Monit. 9, 572-581

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Global-Scale Fate and Transport of Perfluorocarboxylates and Perfluorocarboxylic Acids Emitted from Direct Sources using a Spatially-Resolved Multi-Species Model.

2007. Armitage (et al.). SETAC 17:th Annual Meeting in Europe, Porto, Portugal

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Modelling PCB bioaccumulation in a Baltic food web

2007. Erick Nfon, Ian Cousins. Environmental Pollution 148, 73-82

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Modelling the fate and transport of PFCAs emitted from direct sources using a global-scale chemical fate model.

2007. Armitage (et al.). SETAC North America 28th Annual Meeting, in Milwaukee, Wisconsin, USA.

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Perfluorinated chemical research at ITM

2007. McLachlan, Berger, Cousins. Kemikalieinspektionen

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Quantifying the ocean-to-atmosphere transfer of perfluorinated chemicals via sea spray

2007. M. Reth (et al.). SETAC 17:th Annual Meeting in Europe, Porto, Portugal

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Uncertainty And Spatial Variability in European Multi-Media Fate Models.

2007. M. Hauck (et al.). SETAC 17:th Annual Meeting in Europe, Porto, Portugal

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Interpreting time trends and biomagnification of PCBs in the Baltic region using the equilibrium lipid partitioning approach

2006. Erick Nfon, Ian T. Cousins. Environmental Pollution 144, 994-1000

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Publikationer

Horizontal and Vertical Distribution of Perfluoroalkyl Acids (PFAAs) in the Water Column of the Atlantic Ocean

Lithium-ion battery recycling: a source of per- and polyfluoroalkyl substances (PFAS) to the environment?

Managing PMT/vPvM substances in consumer products through the concepts of essential-use and functional substitution: a case-study for cosmetics

The essential-use concept: a valuable tool to guide decision-making on applications for authorisation under REACH?

ACS Environmental Au─How to Improve the Reach of Your Open Access Research

An Outdoor Aging Study to Investigate the Release of Per- And Polyfluoroalkyl Substances (PFAS) from Functional Textiles

Combined Application of the Essential-Use and Functional Substitution Concepts: Accelerating Safer Alternatives

Combined Use of Total Fluorine and Oxidative Fingerprinting for Quantitative Determination of Side-Chain Fluorinated Polymers in Textiles

Emerging Contaminants: Fluorinated Alternatives to Existing PFAS

European scale assessment of the potential of ozonation and activated carbon treatment to reduce micropollutant emissions with wastewater

Grouping of PFAS for human health risk assessment: Findings from an independent panel of experts

Information Requirements under the Essential-Use Concept: PFA Case Studies br

Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS)

Probing the impact of a phytoplankton bloom on the chemistry of nascent sea spray aerosol using high-resolution mass spectrometry

Sea Spray Aerosol (SSA) as a Source of Perfluoroalkyl Acids (PFAAs) to the Atmosphere: Field Evidence from Long-Term Air Monitoring

Addressing Urgent Questions for PFAS in the 21st Century

Estimating Environmental Hazard and Risks from Exposure to Per- and Polyfluoroalkyl Substances (PFASs): Outcome of a SETAC Focused Topic Meeting

Finding essentiality feasible: common questions and misinterpretations concerning the "essential-use" concept

Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols

Sorption of PFOS in 114 Well-Characterized Tropical and Temperate Soils: Application of Multivariate and Artificial Neural Network Analyses

An (Eco)Toxicity Life Cycle Impact Assessment Framework for Per-And Polyfluoroalkyl Substances

An overview of the uses of per- and polyfluoroalkyl substances (PFAS)

Are Fluoropolymers Really of Low Concern for Human and Environmental Health and Separate from Other PFAS?

Computational material flow analysis for thousands of chemicals of emerging concern in European waters

Environment occurrence of perfluoroalkyl acids and associated human health risks near a major fluorochemical manufacturing park in southwest of China

Levels of per- and polyfluoroalkyl substances (PFAS) in ski wax products on the market in 2019 indicate no changes in formulation

Per- and poly-fluoroalkyl substances (PFAS): Current status and research needs

Role of the air-water interface in removing perfluoroalkyl acids from drinking water by activated carbon treatment

Strategies for grouping per- and polyfluoroalkyl substances (PFAS) to protect human and environmental health

The high persistence of PFAS is sufficient for their management as a chemical class

Children's exposure to perfluoroalkyl acids - a modelling approach

Exploring open cheminformatics approaches for categorizing per- and polyfluoroalkyl substances (PFASs)

Exposure and ecotoxicological risk assessment of mixtures of top prescribed pharmaceuticals in Swedish freshwaters

Global transport of perfluoroalkyl acids via sea spray aerosol

Highly fluorinated chemicals in functional textiles can be replaced by re-evaluating liquid repellency and end-user requirements

Release of Side-Chain Fluorinated Polymer-Containing Microplastic Fibers from Functional Textiles During Washing and First Estimates of Perfluoroalkyl Acid Emissions

Spatiotemporal distribution and isomer profiles of perfluoroalkyl acids in airborne particulate matter in Chengdu City, China

Strengthen the European collaborative environmental research to meet European policy goals for achieving a sustainable, non-toxic environment

The European Collaborative Project SOLUTIONS developed models to provide diagnostic and prognostic capacity and fill data gaps for chemicals of emerging concern

The concept of essential use for determining when uses of PFASs can be phased out

Toward a Comprehensive Global Emission Inventory of C-4-C-10 Perfluoroalkanesulfonic Acids (PFSAs) and Related Precursors: Focus on the Life Cycle of C-6- and C-10-Based Products

Why is high persistence alone a major cause of concern?

Comparing the toxic potency in vivo of long-chain perfluoroalkyl acids and fluorinated alternatives

Efficient removal of perfluorooctane sulfonate from aqueous film-forming foam solution by aeration-foam collection

Facing the rain after the phase out: Performance evaluation of alternative fluorinated and non-fluorinated durable water repellents for outdoor fabrics

Longitudinal trends of per- and polyfluoroalkyl substances in children's serum

Multi-pathway human exposure assessment of phthalate esters and DINCH

Perfluoroalkyl acids and their precursors in floor dust of children's bedrooms - Implications for indoor exposure

Polychlorinated biphenyls (PCBs) as sentinels for the elucidation of Arctic environmental change processes: a comprehensive review combined with ArcRisk project results

Spatial variation in the atmospheric deposition of perfluoroalkyl acids: source elucidation through analysis of isomer patterns

What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review

Zurich Statement on Future Actions on Per - and Polyfluoroalkyl Substances (PFASs)

A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)?

Can the use of deactivated glass fibre filters eliminate sorption artefacts associated with active air sampling of perfluorooctanoic acid?

Early life exposure to per- and polyfluoroalkyl substances (PFASs): A critical review

Estimating human exposure to perfluoroalkyl acids via solid food and drinks: Implementation and comparison of different dietary assessment methods

Estimating uptake of phthalate ester metabolites into the human nail plate using pharmacokinetic modelling

Historical human exposure to perfluoroalkyl acids in the United States and Australia reconstructed from biomonitoring data using population-based pharmacokinetic modelling

Model-predicted occurrence of multiple pharmaceuticals in Swedish surface waters and their flushing to the Baltic Seat

Perfluoroalkyl acids and their precursors in indoor air sampled in children's bedrooms

Probing the relationship between external and internal human exposure of organophosphate flame retardants using pharmacokinetic modelling

Relationships between estimated flame retardant emissions and levels in indoor air and house dust

Toward a Comprehensive Global Emission Inventory of C-4-C-10 Perfluoroalkanesulfonic Acids (PFSAs) and Related Precursors: Focus on the Life Cycle of C-8-Based Products and Ongoing Industrial Transition

Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources

Water-to-air transfer of branched and linear PFOA: Influence of pH, concentration and water type

A large-scale model for simulating the fate & transport of organic contaminants in river basins

Comparative assessment of the environmental hazards of and exposure to perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs): Current knowledge, gaps, challenges and research needs

Contribution of Direct and Indirect Exposure to Human Serum Concentrations of Perfluorooctanoic Acid in an Occupationally Exposed Group of Ski Waxers

Europe-wide estuarine export and surface water concentrations of PFOS and PFOA

Evaluation of human pharmaceutical emissions and concentrations in Swedish river basins

Human exposure, hazard and risk of alternative plasticizers to phthalate esters

Is Ongoing Sulfluramid Use in South America a Significant Source of Perfluorooctanesulfonate (PFOS)? Production Inventories, Environmental Fate, and Local Occurrence

Levels, Isomer Profiles, and Estimated Riverine Mass Discharges of Perfluoroalkyl Acids and Fluorinated Alternatives at the Mouths of Chinese Rivers

Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing