Evaluation of cytotoxicity, dioxin-like activity and estrogenicity of complex environmental mixtures

Complex organic extracts from soils and sediments collected in an industrial region of the Czech Republic were tested with in vitro recombinant cell lines for their potential dioxin-like and estrogenic activity and cytotoxicity. For dioxin-like toxicity tested on H4IIE-luc cells complete dose-responses were obtained with all extracts. The MCF-7-luc cell line used for determination of estrogen receptor-mediated activity was sensitive to the cytotoxic effects of the soil and sediment extracts. Dose dependent cytotoxicity was observed with most samples. Significant estrogenic activity was found in all samples. The toxic or estrogenic equivalents based on the analytically determined concentrations of organic pollutants with known dioxin-like or estrogenic potency were calculated and compared to the bioassay-derived estimates. Fractionation along with mass-balance calculation enabled identification of the most active fraction and classes of compounds. Polycyclic aromatic hydrocarbons were identified as the group of compounds responsible for most of the TCDD-like activity as well as for important portion of estrogenic activity.