Impacts of particulate matter (PM2.5) on the behavior of freshwater snail Parafossarulus striatulus

Fine particulate (PM2.5) is a severe problem of air pollution in the world. Although many studies were performed on examining effects of PM2.5 on human health, the understanding of PM2.5 influence on aquatic organisms is limited. Due to wet deposition, the pollutants in PM2.5 can enter aquatic ecosystems and affect aquatic organisms. This study tested the hypothesis that PM2.5 will negatively affect the behavior of freshwater snail Parafossarulus striatulus (Benson, 1842). Along with PM2.5, a number of components (Al, Pb, and Zn) that are commonly present in PM2.5 were also tested for their effects on the snail's behavior. The snail behavior was scored using the Behavioral State Score (BSS), ranging from 0 (no movement) to 5 (active locomotion and fully extended body). The result shows that high PM2.5 concentration dose (7.75 mg/L) induced a significant decrease in snails' movement behavior, and such reduced movement. The same behavior was also observed for treatments with chemical components related to PM2.5, including aluminum and acidity (pH 5.0). In contrast, a low concentration of PM2.5 (3.88 mg/L), lead, and zinc did not significantly affect snails' behavior. The results suggest that high PM2.5 deposition in water bodies, associated with acidification and some metals, can have an adverse effect on aquatic organisms.