“Environmental risk assessments are used to protect the environment from negative effects by, for example, chemicals. One problem in risk assessments of today is that they often are based on effects on for example mortality or reproduction, measured on the individual level,” says Elin Lundström Belleza new PhD at the Department of Applied Environmental Science (ITM).

Elin used crustaceans that are smaller than 1 millimeter long called harpacticoid copepods. “You could drink a glass of water with these animals swimming around and you wouldn’t even notice”, she says. She continues: “What we really want to protect are populations, and ultimately ecosystems, but how can we find out if effects on mortality and reproduction matter to a whole population?”

Population models

To answer this question, Elin used models called population models to project the effects of sewage water and certain chemicals from individuals to populations. She showed that more complex models were better at measuring hazards for populations than simpler models. In addition, she found that the effects of certain chemicals were more pronounced when tested on populations of crustaceans instead of individuals. “The models are like a virtual laboratory, where you can run experiments many more times than would ever be possible to do in the real world,” says Elin.

¬Elin thinks that the future of assessing risk from chemicals is in population modeling. “Models are powerful tools that can bridge the gap between what we measure in the laboratory and what we want to protect in the environment. They will no doubt bring on a new era in environmental risk assessment, ”she says.