Even though emissions of environmental toxins to Lake Vänern have decreased in recent decades, earlier emissions still remain in land and seabed and run the risk of spreading in the ecosystem.
For example, the levels of dioxin and PCBs in several fish species are still elevated, which poses a threat to human health and limits their value as food fish.
"However, knowledge of the presence of environmental toxins on the bottom of Lake Vänern is relatively poor, which makes it difficult to implement effective environmental measures and reduce the risk of their spreading," says Lovisa Zillén Snowball, director of the Marine Environment unit at SGU in a press release.
Through the survey, SGU hopes to obtain models and scenarios on how the environment in Vänern develops and provide a basis for better prioritization of which environmental measures will be implemented in the future.