FORURENS: Occurrence, dispersal modeling and toxic effects of a multitude of contaminants in Lake Mjøsa - a deep Nordic lake

The project will focus on the occurrence and fate of a multitude of pollutants in Lake Mjøsa. This deep fjord lake is the largest lake in Norway, and it has been supplied with a multitude of both classical and newly discovered, less studied contaminants. Recent studies have proved exceptional high concentrations of brominated flame retardants of the type polybrominated diphenyl ethers (PBDE) in fish and sediments, and elevated concentrations of PCBs, dioxins and mercury have caused consumption restriction s on several fish species. The project is divided into two interconnected workpackages (WP). WP1 will complement earlier studies with more detailed information on persistent organic pollutants (POPs) and mercury (including methyl mercury) in sediments, lake water and food webs. This WP will serve the other two with necessary empirical data and material for their activities. WP2 will further develop mathematical tools to obtain an improved quantitative understanding of the complex and dynamical relatio nships between sources and levels of selected contaminants in the lake ecosystem, including transfer of contaminants through the aquatic food web. It will build upon the modeling experience obtained in various relevant R&D projects, particularly the NFR-f unded SEDFLEX model. An initial module for modeling the dispersal and biomagnification of mercury will be developed. An interdiciplinary workshop will be arranged at the end of the project.