Comparative study of bioconcentration potential and biomarkers in Biomphalaria glabrata exposed to ZnO nanoparticles and bulk ZnO

The uptake of nanoparticles (NPs) by aquatic invertebrates can lead to adverse health effects. The aims of the present study were: 1) to investigate the bioconcentration potential of ZnO NPs or its bulk analogous in Biomphalaria glabrata gastropods by measuring the soft tissue Zn content, and 2) to determine the responses elicited by the exposed snails through the analysis of recognized biomarkers of effect at the subcellular level. Snails exposed to 5 mg/L ZnO NPs or bulk ZnO for 48 h showed a significant higher soft tissue Zn content than control animals, with no significant differences between NPs- and bulk-treated snails. No significant differences were observed in the levels of lipid peroxidation and in the activities of acetylcholinesterase, carboxylesterase and catalase by 48 h-exposure to ZnO NPs or bulk ZnO with respect to control organisms. However, ZnO exposure induced a significant decrease in glutathione tissue content, without a nano-specific effect. The results as a whole encourage further studies to better understand the impact that engineered NPs may have on freshwater invertebrate species.