To Örebro University

Introduction: Given the complex interactions of re-suspension processes and bioavailability of sediment-bound pollutants such as dioxin-like chemicals, there is need for a better integrative understanding of the cause-effect relationship of these pollutants. Currently, the majority of studies investigating potential risks of these chemicals only focus on characterizing sediment extracts via in vitro bioassays, thereby disregarding bioavailability, uptake, metabolism, and elimination rates of these compounds in vivo. To determine to which extent mechanism-specific effects in vitro reflect possible adverse effects in vivo, the research project dioRAMA, involving partnership between the Institute for Environmental Research of RWTH Aachen University and the Department Biochemistry/Ecotoxicology of the German Federal Institute of Hydrology, was established.

Methods: Animals from an elevated trophic level-common roach (Rutilus rutilus)-will be exposed to sediments from two major German rivers. Exposure will be performed in a system that enables a concurrent monitoring of environmental parameters. In parallel, in vitro studies will be conducted to determine dioxin-like potentials of sediment and fish extracts from the in vivo exposure experiments using different cell lines with varying endpoints. Moreover, extract fractionation procedures, using the strategy of effect-directed analysis, will enable the detection of specific contaminant groups responsible for the biological activity observed.

Conclusion: A closer interconnection between applied ecotoxicological science and regulatory needs will facilitate the improved assessment of dioxin-like compounds in sediment and biota. Consequently, this will enable their application in sediment management programs, which is one of the main goals of the dioRAMA project.