The effects of s-metolachlor chronic exposure at concentrations of 1.1 μg/L (maximal real environmental concentration in the Czech Republic), 11 μg/L (environmental relevant concentration) and 110 μg/L on early life stages of marbled crayfish (Procambarus virginalis) was evaluated under laboratory conditions. All s-metolachlor exposures resulted in higher mortality, delay ontogenetic development with accompanied slower growth and excited behaviour (increase of total distance moved and walking speed). Significantly lower superoxide dismutase, catalase, glutathione S-transferase activity and reduced glutathione level was observed at two higher tested concentrations (11 and 110 μg/L) of s-metolachlor compared with the control. S-metolachlor in concentrations 110 μg/L showed alteration of the tubular system of hepatopancreas including focal disintegration of tubular epithelium and notable reduction in epithelial cells number, especially B-cells. In conclusion, potential risk associated with using of s-metolachlor in agriculture, due to effects on non-target aquatic organisms as documented on early life stages of marbled crayfish in this study, should be taken into account.

University of South Bohemia in Ceske Budejovice Faculty of Fisheries and Protection of Waters South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses Research Institute of Fish Culture and Hydrobiology Zatisi 728 2 389 25 Vodnany Czech Republic

References provided by Crossref.org

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Effects of metazachlor and its major metabolite metazachlor OA on early life stages of marbled crayfish