Merging food web contaminant empirical and modeling expertise: Visiting Researcher Dr. Jon Arnot

The iterative process of i) environmental monitoring, ii) model development, parameterization, and application (hypotheses generation), iii) model evaluation (hypotheses testing), and iv) model refinement is a framework that improves understanding of the bioaccumulation phenomenon. This process reduces uncertainty in bioaccumulation, exposure and risk assessment for contaminated sites and for evaluating new and existing chemicals. Dr. Jon Arnot (UTSC) and Dr. Katrine Borgå (NIVA) have extensive background s in bioaccumulation modelling and field measurements, respectively. In the proposed three month research visit to NIVA, Oslo Norway they will join forces to i) expand upon and develop food web models of contaminant accumulation in Norwegian food webs (i. e. Lake Mjøsa), ii) involve NIVA modelling researchers in valuable discussions on the previous implementation of Arnot's AQUAWEB model into the NIVA in-house SEDFLEX model toolbox, and iii) enhance continued collaboration and development of future researc h projects. The research visit project includes the development, parameterization and application of food web bioaccumulation models. The primary model outputs will be steady-state chemical concentrations in biota, and enrichment factors (BAFs, BMFs and T MFs). The models will be evaluated with available monitoring data (e.g. legacy contaminants such as PCBs, DDT, HCH in Lake Mjøsa trout food web, Arctic food webs, Oslo fjord). For legacy POPs such as highly recalcitrant PCBs that show negligible biotransf ormation, the model evaluation will provide guidance for improving the model uncertainty information in applying the model for exposure and risk assessments. For other chemicals for which monitoring data exist (e.g. PBDEs, HBCDD), the evaluated models wil l be used to estimate biotransformation rate constants.