95th National Congress of the Italian Society for Experimental Biology | Trieste, Italy, 12-15 April 2023

The indiscriminate use of pesticides ends with concerns about their effects on the environment, and on non-target organisms. In this point of view, aquatic ecosystems are the most valuable for living organisms, and residual concentrations of pesticides and their metabolite products pose a threat to them. Chloroacetanilide metabolite propachlor ethanesulfonic acid (PROP-ESA) belongs to these pollutants and is founded in aquatic ecosystems worldwide. Due to its chemical-physical properties may be easily absorbed throughout the soil and water, resulting in an adverse impact on aquatic organisms and humans via the trophic chain. This study investigated the bioaccumulation of PROP-ESA in soft tissue and its effect on oxidative stress in the gills and digestive gland of the model organism Mytilus gallo-provincialis. Mussels were exposed to PROP-ESA at 3.5 μg/L, the environmental concentration and its tenfold 35 μg/L for 10-d and 20-d. Bioaccumulation of PROP- ESA in soft mussels’ tissue is presented with the bioconcentration factor (BCF). Oxidative stress measured in gills and digestive glands is shown by meas-uring superoxide dismutase (SOD) activity, levels of lipid peroxi-dation (LPO) and oxidatively modified protein (OMP). Results showed that PROP-ESA increases in tissue at higher concentra-tions and longer exposure times. The evaluation of oxidative stress biomarkers showed a different trend between gills and digestive gland. Protein carbonylation (OMP) increased in the gills at both concentrations only after the shortest exposure time, no changes were reported in the digestive gland. TBARS levels, a marker of LPO, increased in both tissues after 10-d of exposure but remained high only in the digestive gland after 20-d of expo-sure at the lower concentration. An increased activity of SOD enzyme was observed in gills after 20-d of exposure at both con-centrations. In conclusion, this study shows that the M. gallo-provincialis can absorb the pollutant into its tissue, but that over long periods of exposure an adaptation of the body to the stress conditions imposed by the pollutant may occur.