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Toxic effects of nanomaterial-adsorbed cadmium on Daphnia magna

Gao, Minling, Zhang, Ze, Lv, Mengting, Song, Wenhua, Lv, Yuhua
Ecotoxicology and environmental safety 2017
Daphnia magna, absorbents, acute toxicity, adsorption, aquatic organisms, cadmium, cadmium chloride, catalase, cell membranes, guidelines, malondialdehyde, nanomaterials, peroxidase, remediation, risk, soil, superoxide anion, superoxide dismutase
Chemical immobilization technologies involving the use of chemical absorbents such as nanomaterials have been recommended for the remediation of Cd-contaminated water and soil. The impact of nanomaterials or nanomaterials coexisting with other contaminants on aquatic organisms has been reported, but information on the toxic effects of nanomaterial-adsorbed cadmium (Nano-Cd) on aquatic organisms is lacking. This study aimed to investigate the acute and sub-acute toxicity of Nano-Cd on Daphnia magna by using a method developed based on the standard Organisation for Economic Co-operation and Development (OECD) 202 guidelines. The toxicity of cadmium chloride (Cd2+), nano-manganese dioxide-cadmium (nMnO2-Cd), 20nm nano-hydroxyapatite-cadmium (nHAP20-Cd), and 40nm nano-hydroxyapatite-cadmium (nHAP40-Cd) to D. magna was in the following order: Cd2+> nMnO2-Cd > nHAP20-Cd > nHAP40-Cd. Further, nMnO2-Cd, nHAP20-Cd, and nHAP40-Cd showed acute toxicity to D. magna of level II grade according to the Commission of the European Communities and OECD standards. Exposure to low and medium, but not high, Nano-Cd concentrations increased the activities of peroxidase, superoxide dismutase, catalase, and anti-superoxide anion. Thus, Nano-Cd, particularly at high concentrations, could exert oxidative damage in D. magna. An increase in Cd2+ and Nano-Cd concentrations gradually increased the malondialdehyde content, indicating cell membrane damage caused by the production of excessive O2-. Thus, the use of nanomaterials after adsorption of Cd is associated with a potential risk to aquatic organisms.