Cadmium (Cd) is widely distributed in aquatic environments and is extremely toxic metal commonly found in industrial settings as a key component in the production of nanoparticles such as Cd-based quantum dots (QD). Quantitative information on the accumulation of Cd - incorporated in QD structure and Cd - in a salt form to early developmental stages of fish, such as embryos and larvae is limited. The main aims of the present study were to determine the concentration of Cd in experimental water after exposure to sublethal concentrations of QD (CdSe/ZnS-COOH) and Cd (CdCl₂∙H₂O) singly to rainbow trout Oncorhynchus mykiss embryos and larvae, and to evaluate accumulation potential of Cd in the whole body of the fish embryos and larvae exposed to QD and Cd singly. Experimental studies at the early trout developmental stages were performed under static conditions. The concentration of Cd atoms (within QD structure) was 10^-6 M. Meanwhile, the Cd concentration in the CdCl₂ solution was 1.8 x 10^-8 M. When compared, the Cd concentration in the QD solution was 56 times higher than in the CdCl₂ solution. Different concentrations of Cd demonstrated distinct accumulation potential in rainbow trout embryos and larvae, and it depends on the conditions of exposure (QD or single–Cd exposures). Accumulation of Cd in embryos and larvae is uneven (very large variation) and, possibly, depends on the biotic and abiotic factors. This comparative analysis indicated, that the bioconcentration of Cd from the QD tends to increase with increasing duration of exposure, and Cd in the ionic form, on the contrary: the more bioconcentrated at the beginning of exposure.

DOI: https://doi.org/10.3846/enviro.2017.014