Chronic toxicity of contaminated sediments on reproduction and histopathology of the crustacean Gammarus fossarum and relationship with the chemical contamination and in vitro effects

Purpose The aim of the present study was to investigate possible relationships between the sediment contaminants and the occurrence of intersex in situ. Two of the studied sediments were from polluted sites with increased occurrence of intersex crustaceans (Lake Pilnok, black coal mining area in the Czech Republic, inhabited by the crayfish Pontastacus leptodactylus population with 18% of intersex; creek Lockwitzbach in Germany with Gammarus fossarum population with about 7% of intersex). Materials and methods Sediments were studied by a combined approach that included (1) determination of concentrations of metals and traditionally analyzed organic pollutants such as polychlorinated biphenyls, pesticides, and polycyclic aromatic hydrocarbons (PAHs); (2) examination of the in vitro potencies to activate aryl hydrocarbon (AhR), estrogen (ER), and androgen receptor-mediated responses; and (3) in vivo whole sediment exposures during a 12-week reproduction toxicity study with benthic amphipod G. fossarum. Results and discussion Investigations showed that Lake Pilnok was highly contaminated by powdered waste coal, contained high concentrations of PAHs (up to 12 μg/g dry weight), and exhibited various effects in biotests (high concentrations of AhR and ER agonists were determined by in vitro assays with H4IIE.luc cells and yeast luciferase reporter gene assays). Less pronounced effects were observed in Lockwitzbach and Steinlach creek sediments. Long-term in vivo laboratory exposures with G. fossarum resulted in significant mortalities and sex-specific toxicities (reflected in hepatopancreas histopathology). Significant effects on the reproduction-related parameters were observed at Lake Pilnok sediments, which elevated numbers of newly hatched individuals and stimulated reproduction cycle in females (larger portions of mature oocytes in comparison to other variants). Conclusions Results of the present study indicate that sediments from Lake Pilnok contain a large portion of dioxin-like, estrogenic, and anti-androgenic compounds, which stimulated fecundity in G. fossarum. Although some effects might be attributed to PAHs, most of the bioactive compounds could not be detected by traditional instrumental analyses. Possibly, bioavailable fractions of the maceral (solid coal mass rich in organic compounds) could have contributed to the observed activities, but only few studies investigated its biological effects, and it will require further research. The present study emphasizes the need for integrated assessment of contaminated sediments to elucidate their ecotoxicological impacts.