Fish exposed to polyethylene with chemical pollutants absorbed from the marine environment are shown to bioaccumulate these pollutants and may suffer from liver toxicity. The findings are reported in the journal Scientific Reports this week.

Small plastic debris is ubiquitous in marine environments, the majority of which is microscopic (less than 1 mm) and can be ingested by a wide range of species. Yet the potential health impacts associated with ingestion by fish and marine invertebrates of the complex mixture of plastic and accumulated pollutants remain uncertain.

Chelsea Rochman and colleagues examined the effects of chronic dietary exposure to environmentally relevant concentrations of low-density polyethylene plastic on the Japanese medaka (Oryzias latipes), a common model fish species. They show that polyethylene ingestion may contribute towards the bioaccumulation of potentially hazardous substances in fish, and the exposed fish also tended to experience adverse health effects in the liver. The toxicity seems to be a consequence of both the absorbed pollutants and plastic material. The fish showed signs of hepatic stress, more so in fish that were exposed to marine-treated plastic (deployed in an urban bay), rather than to virgin (pre-production) plastic.

The results offer baseline information regarding the bioaccumulation of chemicals and the potential associated health effects from plastic ingestion in fish. The authors note that future work is needed to study the effect of plastics on other marine species, and to examine which types of material and chemical pollutant compositions and concentrations may have the biggest health impacts on marine creatures.