The influence of surface waters on the bioavailability and toxicity of zinc oxide nanoparticles in freshwater mussels

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology Vol. 219; pp. 1 - 11
• Main Authors: Gagné, F., Auclair, J., Turcotte, P., Gagnon, C., Peyrot, C., Wilkinson, K.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2019
• Subjects: Mussels; Surface waters; Toxicity; Zinc oxide nanoparticles; Surface waters; Toxicity; Mussels; Zinc oxide nanoparticles
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cbpc.2019.01.005

The release of engineered nanoparticles in the aquatic environment could pose a threat to the biota. The purpose of the study was to examine the influence of surface water characteristics on zinc oxide nanoparticles (nZnO) and ZnS04 toxicity to the freshwater mussel Dreissena polymorpha. Mussels were exposed to an equivalent concentration of 25 μg/L Zn as either nZnO or ZnSO4 for 96 h at 15 °C in 4 types of surface waters: green water (high conductivity and pH with low natural organic matter content), brown water (low conductivity and pH with high natural organic matter content), diluted municipal effluent (high conductivity and pH with high urban organic matter content) and aquarium water (treated green water with organic matter removed). After the exposure period, mussels were analyzed for air-time survival, total and labile Zn levels in tissues, lipid metabolism (phospholipase A2, triglycerides levels) and oxidative stress (glutathione S-transferase, arachidonate cyclooxygenase, lipid peroxidation). The data revealed that mussels exposed to ZnSO4 in controlled aquarium water accumulated more total and labile Zn tissues, decreased oxidative stress and triglycerides and increased air time survival. While nZnO had few effects in aquarium water, oxidative stress was enhanced and total Zn in tissues were decreased in brown water and diluted municipal effluent and triglycerides were higher in nZn-exposed mussels in brown water. Air-time survival was decreased in mussels kept in green water and nZnO. It was also decreased in mussels exposed to ZnSO4 in green water and diluted municipal effluent. In conclusion, the fate and toxic effects of Zn could be influenced by both the chemical form (nanoparticles or ionic Zn) and surface water properties in freshwater mussels. [Display omitted] •nZnO toxicity could change in the presence of green, brown surface waters and municipal effluent.•The toxicity of nZnO differed from dissolved Zn.•Oxidative stress is enhanced in the presence of 10% municipal effluent.