Trophic transfer of microplastics enhances plastic additive accumulation in fish

Abstract

A variety of chemical additives are incorporated into plastics during their production process to give desirable properties. Although studies have suggested that microplastic ingestion can lead to accumulation of these chemicals in marine organisms, none provided the direct evidence in fish species. Here, we demonstrated the tissue accumulation of chemical additives in fish following microplastic ingestion. We exposed fish (Myoxocephalus brandti) to polyethylene microplastics compounded with brominated flame retardants (BFRs; BDE209, DBDPE) and ultraviolet stabilizers (UVs; UV-234, UV-327, BP-12) suspended in the water column, or to mysids (Neomysis spp.) pre-exposed to the same microplastics. Our results showed a maximum of 345-fold higher concentrations of additives in fish exposed to microplastics than the ambient sample. Also, fish fed plastic-exposed mysids accumulated significantly greater concentrations of BFRs in muscle than fish exposed to microplastics suspended in the water column (p < 0.001). This indicates that trophic transfer of microplastics has greater contribution to tissue accumulation of BFRs in fish than the waterborne ingestion. In contrast, no significant difference in the accumulation of UVs was found between the treatments, except for UV-327 in liver. These results suggests that the relative contribution between direct ingestion of microplastics from the water column and indirect ingestion via trophic transfer on tissue accumulation of additives in fish varies among compounds. Compounds with high molecular weight and high hydrophobicity like BDE209 and DBDPE were considered difficult to leach out from plastics, however, our study showed that trophic transfer of microplastics can facilitate the accumulation of such compounds from plastics to fish.

Estimating the Bioaccumulation Potential of Hydrophobic Ultraviolet Stabilizers Using Experimental Partitioning Properties

“…In another study, UV326, UV328, and UV329 were found at concentrations ranging from 1.34 to 45.6 ng g −1 (dry weight, dw) on Gran Canaria Island (Spain) [ 50 ]. Hasegawa et al recently showed similar accumulation patterns between direct ingestion from the water column and indirect exposure via the trophic transfer pathway for UV327 in marine fish [ 51 ]. In a recent monitoring study, the sum of nine benzotriazole UV stabilizers (including the five target chemicals in this study) were found in river water (17.0–32.5 ng L −1 ) and sediment (2.0–22.6 ng g −1 , dw) in Korea [ 52 ].…”