Metal bioaccumulation, oxidative stress, and biochemical alterations in the freshwater snail (Galba truncatula) exposed to municipal sewage

Abstract

Urban wastewater contains various detergents, pesticides, pharmaceutical medications, cosmetics, hygiene products, and heavy metals. Discharge of municipal sewage into surface water affects the health of aquatic organisms through altering biochemical markers and accumulating heavy metals in various tissues. The present study aimed to evaluate the toxic effects of municipal sewage on the biochemical markers and bioaccumulation of cadmium and lead in freshwater snail (Galba truncatula) during 14 days. Concentrations of toxic metals in the snails were determined using ICP-OES-PerkinElmer, and biochemical parameters were measured via UV-Vis spectroscopy. The results indicated significantly lower levels of glycogen and total antioxidant in the cells, as well as the significantly lower activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, acetylcholine esterase, catalase, and glucose-6-phosphate dehydrogenase in the Galba truncatula exposed to sewage compared to the control. However, the activities of lactate dehydrogenase ,glutathione peroxidase, and malondialdehyde were significantly higher in the snails exposed to sewage compared to the control. Moreover, bioaccumulation of cadmium and lead was observed to increase in the experimental groups exposed to sewage. Alterations in biochemical parameters in the G. truncatula exposed to sewage could be due to the toxic effects of various environmental pollutants in municipal wastewater. According to the findings, oxidative damage to the vital tissues of G. truncatula was associated with the bioaccumulation of cadmium and lead, depletion of total antioxidant levels, changes in biochemical parameters, and lipid peroxidation in soft tissues.