Influence of nanoparticles of industrial plastics on model fish Danio rerio (Hamilton, 1822)

Background. Nanoparticles of industrial plastics are considered as potentially hazardous contaminants of water bodies due to their ability to penetrate living cells by endocytosis. Relevance. Study of the effects of nanoplastics on hydrobionts at concentrations expected for natural waters is crucial for the implementation of environmental protection measures in the context of societal industrial development. Aim. In this work, the effect of polystyrene, polyvinyl chloride and polymethyl methacrylate nanoparticles on a model organism—fish Danio rerio (Hamilton, 1822)—has been studied. Methods. Fluorescent nanoparticles with a diameter of 110–180 nm were used; their dispersions did not contain toxic stabilizers and preservatives. Cultivation in the presence of nanoplastic was carried out starting from the second day after fertilization for 20–30 days at high (1–15 mg/L) and three months at low (0.01–0.1 mg/L) concentrations. Results. Nanoparticles were found to have no significant effect on embryo and fry survival at concentrations of 0.01–0.1 mg/L, which exceeds the expected presence of nanoplastic in natural waters. At higher concentrations (5–15 mg/L), survival rates decreased. The use of fluorescent nanoparticles showed that plastic is ingested by fish through food sources capable of assimilating nanoparticles (infusoria), and when their feed is replaced by larger organisms (nauplii), the fish are cleared of nanoplastic. Adult fish surviving influence of nanoplastic are able to reproduce at the level of control groups, and in case of exposure to high concentration of polymer (15 mg/L) there are no abnormalities in embryo development, in contrast to the individuals in the control groups. It can be assumed that the high concentration of nanoplastic acts as a selection factor, reducing the proportion of individuals with genetic abnormalities, although this hypothesis needs careful testing using molecular genetics and biochemical methods. Conclusion. The results obtained indicate that there is no significant effect of nanoplastics on D. rerio at possible natural concentrations; these results can be used to develop methodological approaches to studying the effects of nanoplastics on other organisms, including commercial fish.