Polar compounds dominate in vitro effects of sediment extracts

Sediment extracts from three polluted sites of the river Elbe basin were fractionated using a novel on-line fractionation procedure. Resulting fractions were screened for mutagenic, aryl hydrocarbon (AhR)-mediated, transthyretin (TTR)-binding and estrogenic activities and their potency to inhibit gap junctional intercellular communication (GJIC) to compare toxicity patterns and identify priority fractions. Additionally, more than 200 compounds and compound classes were identified using GC-MS/MS, LC-MS/MS and HPLC-DAD methods. For all investigated endpoints major activities were found in polar fractions, which are defined here as fractions containing dominantly compounds with at least one polar functional group. Nonpolar PAH fractions contributed to mutagenic and AhR-mediated activities while inhibition of GJIC and estrogenic and TTR-binding activities were exclusively observed in the polar fractions. Known mutagens in polar fractions included nitro- and dinitro-PAHs, azaarenes and keto-PAHs, while parent and monomethylated PAHs like benzo[a]pyrene and benzofluoranthenes were identified in non-polar fractions. Additionally, for one sample high AhR-mediated activities were determined in one fraction characterized by PCDD/Fs, PCBs and PCNs. Estrone, 17ß-estradiol, 9H-Benz[de]anthracene-7-one, triclosan and 4-nonylphenol were identified as possible estrogenic and TTR-binding compounds. Thus, not only nonpolar compounds like PAHs, PCBs and PCDD/Fs but also the less characterized and investigated semipolar and polar substances should be considered as potent mutagenic, estrogenic, AhR-inducing, TTR-binding and GJIC inhibiting components for future studies. Effect-directed analysis of three sediment extracts and five in vitro endpoints suggests polar compounds as dominant substances for investigated effects.
JRC.DDG.H.5-Rural, water and ecosystem resources