The influence of surface waters on the bioavailability and toxicity of copper oxide nanoparticles to freshwater mussels

The increased commercial use of copper oxide nanoparticles (nCuO) led to the release of nanoparticles in wastewaters potentially harming the aquatic biota. The purpose of this study was to determine the toxic action of nCuO and dissolved Cu (II) to Dreissena bugensis freshwater mussels placed in 4 types of surface waters: aquarium, green (high conductivity), brown (high organic carbon) and 10 % municipal effluent (high conductivity and anthropogenic source of organic carbon). Mussels were exposed to 50 µg/L of nCuO or Cu (II) for 96 h at 15 °C in the above waters. The results revealed that the total Cu loadings were higher in mussels placed in organic-rich waters (brown and effluent) and exposed to either forms of Cu. Tissue Cu contents were correlated with air-time survival, lipid peroxidation, protein-ubiquitin levels and DNA strand breaks. Both surface water types and Cu forms influenced Zn (II) mobilization, glutathione S-transferase activity and protein turnover (ubiquitin binding). Based on the surface water properties, Cu (II) was more influenced by the levels and origin of the organic carbon content while nCuO was more influenced by the total suspended solids. In conclusion the toxicity of nCuO could be influenced by surface waters properties expecially when similar physiological targets are impacts by these treatments.