Bioaccumulation of environmental organic pollutants in freshwater organisms - Biotransformation and its significance

Bioaccumulation, as a consequence of interaction between organism and contaminants, is an unfavorable symptom for individual organism or/and its population in view of ecotoxicology. As the contaminants are accumulated, they are partly biologically transformed and then excreted. This process leads to lower bioaccumulation and less toxicity in most cases. Due to lack of data on biotransformation products (BTPs) and their contributions to bioaccumulation in aquatic organisms, the entire processes of bioaccumulation possibly explaining chemical fate and toxicity is still not well understood. Fortunately, with highly developed analytical tools, i.e. high resolution mass spectrometry, it becomes feasible to identify BTPs and track their pathways through biological processes responding to chemical exposure. Information about BTPs can be applicable to assess ecotoxicological risks posed on aquatic organisms accumulating environmental pollutants. In addition rules governing biotransformation can be developed and feed into appropriate predictive models.

The goal of the present study is to estimate bioaccumulation factors of selected environmental organic pollutants for freshwater organisms, e.g., Daphnia magna, Gammarus pulex, to identify BTPs and their major pathways, and to evaluate contribution of biotransformation to overall bioaccumulation.

Funding:

Swiss National Science foundation, Eawag

Publications:

Jeon, J., D. Kurth, J. Hollender. 2013. Biotransformation pathways of biocides and pharmaceuticals in freshwater crustaceans based on structure elucidation of metabolites using high resolution mass spectrometry, Chem. Res. Toxicol. 266: 313-324.

Kretschmann, A., R. Ashauer, J. Hollender, B. Escher. 2012. Toxicokinetic and Toxikodynamic Model for Diazinon Toxicity – Mechanistic Explanation of Differences in the Sensitivity of Daphnia magna and Gammarus pulex, Environ. Toxicol. Chem. 31: 2014–2022.

Kretschmann, A., R. Ashauer, K. Hitzfeld, P. Spaak, J. Hollender, B. Escher. 2011. Mechanistic Toxicodynamic Model for Receptor-mediated Toxicity of Diazoxon, the Active Metabolite of Diazinon, in Daphnia magna, Environ. Sci. Technol. 45: 4980-4987.

Kretschmann, A., R. Ashauer, T. Preuss, P. Spaak, B. Escher, J. Hollender. 2011. Toxicokinetic Model Describing Bioconcentration and Biotransformation of Diazinon in Daphnia magna, Environ. Sci Technol. 45:.4995-5002. (awarded by German Chemical Society (GDCh), Division Environmental Chemistry and Ecotoxicology)