Impact of the Heavy Metals on Some Species of Freshwater Snails During Two Seasons on Al-Shaeir Island, Qalubia, Egypt

This study highlights significant heavy metal pollution on Al-Shaeir Island, Qalubia, Egypt, during 2022 and 2023 with levels exceeding international standards. The bioaccumulation of Fe, Mn, Pb, and Cd in five freshwater snail species (Cleopatra ferruginea, Helisoma duryi, Lanistes carinatus, Physa acuta, and Theodoxus niloticus) underscores the potential ecological risks. Selected for their bioindicator potential, these species provide crucial insights into heavy metal impacts on freshwater ecosystems, emphasizing the need for further monitoring and remediation efforts. Water analysis revealed metal concentrations exceeding FAO and USEPA standards, indicating significant pollution. Bioaccumulation factor (BAF) analysis showed species-specific variations, with Physa acuta exhibiting the highest accumulation levels. Elevated nitric oxide (NO) levels in all tested species suggest a physiological response to metal exposure. Increased ALT and AST enzyme activities correlate with higher BAFs, indicating potential liver toxicity. Histological examination revealed excessive lipofuscin accumulation in digestive glands, suggesting oxidative stress and cellular damage. Additionally, comet assay results confirmed significant DNA damage, highlighting the genotoxic effects of heavy metal contamination. These findings emphasize the role of freshwater snails as bioindicators and highlight the importance of environmental monitoring in polluted aquatic ecosystems to support sustainable development.