Toxicological effects of nanoplastics and phenanthrene to zebrafish (Danio rerio)

Abstract Despite the known hazards to wildlife, plastic waste to waterways and oceans continues to increase at alarming rates every year. Nanoplastics are a breakdown product of plastic debris in the environment (0.1–100 nm). Their small size renders them bioavailable, and they are likely to accumulate/adsorb persistent organic pollutants, which could increase their toxicity. In this study, we evaluated the effects of nanoplastics and phenanthrene on the early life stages of zebrafish. Zebrafish embryos were exposed to fluorescent nanoparticles and observed with fluorescence microscopy. Polystyrene nanoplastics (80 nm) attached to the embryonic chorionic membrane and were ingested when zebrafish reached 144 h after fertilization, the point at which they first open their mouth, as observed by the fluorescence in their intestines. Exposure alone or in combination with phenanthrene resulted in zebrafish pericardial edema, spinal curvature, increased embryonic heart rate, shortened body length, and increased mortality. Co-exposure to 5 mg/L nanoplastics and 0.1 mg/L phenanthrene caused more negative effects on length, teratogenicity and mortality of zebrafish embryos than the corresponding concentrations of single exposure. This study provides clear evidence that nanoplastics can be ingested by zebrafish larvae, thus future work to assess the toxicological effects is important to marine wildlife management.