Microplastics as a vector of hydrophobic contaminants: Importance of hydrophobic additives

ABSTRACT Despite a recent boom in research on the environmental fate, distribution, and harmful effects of chemical substances associated with marine plastic debris, no consensus has been reached on whether chemicals originating from microplastics cause serious environmental harm. For the risk assessment of chemical contaminants associated with microplastics, it would be useful to group organic chemicals into 2 categories: additives and nonadditives. Whereas plastic particles are not likely to be diffuse sources of chemicals that are not intentionally added to plastic products, continuous leaching of additives would result in higher concentrations, at least at a local scale. Unlike plasticizers and flame retardants, which have been relatively well investigated, antioxidants and photostabilizers have been rarely studied, even though many of them are highly hydrophobic and are not readily biodegradable. More research on the fate and effects of chemicals via microplastics should focus on those additives. Integr Environ Assess Manag 2017;13:494–499. © 2017 SETAC Key Point Because studies are lacking to evaluate potential risks of plastic additives except for plasticizers and brominated flame retardants, we propose that more research on the fate and effects of micropollutants via microplastics should focus on other hydrophobic additives.