Effect-Directed Analysis of Ah-Receptor Mediated Toxicants, Mutagens, and Endocrine Disruptors in Sediments and Biota

Abstract

Sediments and associated biota represent important sources for the exposure of aquatic organisms to environmental toxicants including dioxin-like compounds, genotoxic chemicals, and endocrine disruptors. One of the key challenges that environmental toxicologists and risk assessors are facing is the characterization and assessment of toxicological risks associated with such complex matrices such as sediments. Therefore, approaches have been developed supplementing chemical analysis with bioanalytical techniques that make use of the specific properties of certain groups of chemicals to interfere with specific biological processes. This type of analysis has been coined effect-directed analysis (EDA), and is based on a combination of fractionation procedures, biotesting, and subsequent chemical analyses. In this chapter, we review the current state of the art of EDA regarding the assessment of sediment and biota samples for dioxin-like, genotoxic, and endocrine disrupting potentials. We discuss in vivo and in vitro screening concepts that are used in combination with fractionation and chemical analytical techniques to aid in the risk assessment of these chemical groups in sediments and biota. Advantages and disadvantages of current EDA strategies are considered, and recommendations for more realistic and relevant EDA approaches are given. Specifically, these include the use of optimized biotest-batteries covering a broad range of different endpoints as well as the inclusion of in vivo tests, and the parallel assessment of ecologically relevant parameters such as benthic community structure. Furthermore, the need for refinement and standardization of current sediment EDA approaches that allow capturing and assessing exposures to unknown or emerging chemicals such as endocrine disruptors, perfluorinated compounds, or polybrominated and mixed halogenated dibenzo-p-dioxins and -furans is discussed.