What does the freshwater clam, Corbicula largillierti, have to tell us about chlorothalonil effects?

Chlorothalonil (CLT) is a broad spectrum, and non-systemic fungicide applied in foliar structures to prevent and treat pathogens. This compound reaches to aquatic environments and affects the biota. In this context, the main goal of this study was to assess the effects of CLT at biochemical, tissular, and individual levels of biological organization using the invasive bivalve Corbicula largillierti as a bioindicator species. Clams were exposed to different sublethal concentrations (0, 10, 20 and 50 mu g. L-1 CLT) for 96 h. At biochemical level, the enzymatic activity (Glutathione-s-Transferase, Catalase, Acetyl-, Butiryland Carboxyl-esterases) and lipid peroxidation were measured in gills and the visceral mass. Also, the digestive gland morphometry through quantitative histological indexes was registered at the tissular level. Finally, filtering activity and burial behavior at the individual level were measured. At the highest CLT concentration, the most significant changes were observed in enzymatic activity (except for butyrylcholinesterase), lipid peroxidation and in digestive gland morphometry. It was also registered increases of the filtering activity and the latency time to burial. Most of the biomarkers assessed showed significant responses under CLT exposure. Therefore, taking into account that C. largillierti was affected by CLT, it can be expected that other species could be in a potential risk if this fungicide is present in freshwater systems.

Automated summary

This study evaluated the effects of Chlorothalonil on the invasive bivalve Corbicula largillierti at biochemical, tissular, and individual levels, finding significant impacts on enzymatic activity, lipid peroxidation, and digestive gland morphometry at higher concentrations. Additionally, filtering activity and burial behavior were also affected, indicating potential risks to other species in freshwater systems under Chlorothalonil exposure.