Toxicokinetic/toxicodynamic-based risk assessment of freshwater fish health posed by microplastics at environmentally relevant concentrations

The pervasive contamination of microplastics (MPs) in freshwater ecosystems is of emerging concern. Mechanistic link between exposure and effect on assessing health risk of freshwater fish posed by environmental MPs, however, is more limited. Our study filled this gap by developing a toxicokinetic/toxicodynamic (TVTD)-based risk assessment framework to examine health effects of zebrafish and red tilapia responses to environmental concentrations of MPs appraised with a variety of valuable published data on a global scale. We assessed organ-specific TK parameters and mean residence times for polystyrene (PS)-MPs-exposed freshwater fish in size- and concentration-dependent manners. We estimated the relatively sensitive benchmark concentrations (BMCs) of PS-MPs for oxidative stress in zebrafish and detoxification in red tilapia to be similar to 1.0 and similar to 119 mu g g(-1), respectively. Based on continental scale MPs trends, the high MPs concentrations were over Asia, with a mean value of 36 mg L-1. Given metabolic disturbances in zebrafish and red tilapia as bioindicators, we found that MPs pollution was highly likely to enhance fish health risks and that this factor must therefore be considered in evaluations of MPs susceptibility of freshwater fish. Our TK/TD-based risk scheme could help inform intensified efforts to mitigate environmental MI's pollution in order to benefit freshwater fish species and people who depend on healthy stocks of different fish. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study developed a toxicokinetic/toxicodynamic-based risk assessment framework to examine the health effects of zebrafish and red tilapia in response to environmental concentrations of microplastics. The findings suggest that microplastic pollution is likely to enhance fish health risks and should be considered in evaluations of freshwater fish susceptibility to microplastics.