Ecotoxicological effect of CdTe quantum dots on Eisenia andrei

Abstract

Nanotechnology is a modern developing discipline producing a large quantity of consumer products, likely resulting in waste materials during the upcoming decades. Engineered nanoparticles with unique physicochemical characteristics are scientifically investigated, determining fate and behaviour for environmental risk assessment. Exposure of the chemical compound in artificial OECD soil provides an indication to determine the fate and behaviour of nanoparticles. During this study acute toxicity test were performed over a range of concentrations to determine the effect of cadmium tellurium quantum dots (Cd/Te QD’s) with representable functional groups (COOH; PEG; NH₃) as well as cadmium chloride (CdCl₂) and tellurium tetrachloride (TeCl₄) on the model organism, Eisenia andrei. Effects were determined by performing the Earthworm Reproduction Test (ERT) utilizing the Organization for Economic Cooperation and Development (OECD) guideline 222. The bio-indicator species were exposed to increasing concentrations of QD’s (5; 30; 100; 500 mg/kg), CdCl₂ (100 and 500 mg/kg) and TeCl₄ (500 mg/kg) as a positive control for 28 days. From this the ECx; LCx; LOEC; and NOEC were determined. Soil samples were left for an additional 28 days to assess the effect of the test chemicals on the reproductive output of the earthworm species. Sublethal stressors of exposed adult organisms were further assessed by using biomarkers for an integrative biological response (IBR) index. Biomarkers included catalase activity (CAT), Superoxide dismutase (SOD), malondidialdehyde (MDA) and cellular energy allocation (CEA). Bioaccumulation of the test chemical were determined by digestion of animal tissue exposed to selected concentrations. Results obtained will give an indication of nanomaterial toxicity at different concentrations with different functional groups on the earthworm E. andrei.