Assessment of mixture toxicity of compounds in discharges to the North Sea and coastal areas of Norway

The North sea and coastal areas of Norway receive input of pollutants from various sources including disharges from land, maritime and offshore oil production activitites, leakage from contaminated sediments and long-range atmospheric transport. These com pounds exist as complex mixtures in the recipient and may consequently evoke effects through combination toxicity (mixture toxicity). Due to lack of knowledge on the combined effects of marine pollutants and their mechanisms of effect, prediction of envir onmental impact and assessment of environmental risk are often assessed based on individual components and lack the ability to integrate combined toxicity, multiple mechanisms of effect and long-term effects due to more subtle mechanisms of toxic action. The present project aim to develop a toolbox and use predictive models for assessment the mixture toxicity of compounds in typical exposure scenarios of Norwegian coastal and North sea areas. The results will be based on experimentally derived data and provide procedures for how to implement mixture toxicity into predictive impact models and existing environmental risk assessment models. These objectives will be achieved through use of a in vitro and in vivo experimental systems with clearly defined tox ic endpoints, use of environmental relevant exposure mixtures, and use of state-of the-art mixture toxicity prediction models. As an evaluation of the generic modelling approach to assessing mixture toxicity, these models will be used to predict toxicity in complex environmental samples such as contaminated harbour sediments and costal discharges. The project is a multi-disciplinary initiative between research groups in Germany, United Kingdom, and Norway and NIVA will host a Ph.D. student that will also perform work at the different collaborating laboratories.