Study finds microplastics in 50 percent of UK freshwater insect samples

19 Nov 2018 --- Although much attention has been paid to the presence of plastic pollution in marine environments, a new UK study has shown that microplastics are also present in river environments after 50 percent of river insects taken from South Wales were found to contain microplastics.

Significant sources of microplastic pollution include plastic textile fibers and degrading macroplastics usually deriving from land. From there, a major component of the flux of land-derived plastic particles into water is likely to arise from Wastewater Treatment Works (WwTWs) or associated storm overflow systems that discharge into rivers, the study notes. Past studies looking at microplastics in freshwater organisms have largely looked at fish, but this study focused on smaller organisms: insects.
 
The researchers focused on river organisms living upstream and downstream of five UK WwTWs. Microplastics occurred in half of the organisms, at all sites. As a result, the researchers are calling for increased caution and close attention to freshwater ecosystems in future microplastics research.

The data demonstrate the presence of microplastics in multiple species of riverine macroinvertebrates, thereby highlighting a potential risk posed to freshwater ecosystems, and signposting the need for further work, according to the researchers. In particular, research is required to link target organisms to the sources and influx of plastics, to assess the transfer of microplastics within freshwater food networks, they add.

The direct effect on mammals is not yet known.

This study joins a host of studies that have identified microplastics in the environment and among wildlife. 

Most recently, scientists detected for the first time plastic microfibers in the stool of wild animals. A team of Morris Animal Foundation-funded researchers at the University of Georgia found this form of microplastics in the stool of South American fur seals by examining droppings from pinnipeds. The team believes that this form of examination is an efficient way to monitor environmental levels of microfiber and microplastic in the environment.

Last month, new research from the Medical University of Vienna and the Environment Agency Austria found particles made of polypropylene (PP), polyethylene terephthalate (PET) and other microplastics in human stools.

Also in October, a new investigation into the published literature on microplastics found “significant gaps in our understanding of the effects” of the less than 5mm sized plastic particles on the environment. The study authors Emily Burns and Alistair Boxall are calling for “better quality and more holistic monitoring studies alongside more environmentally realistic effects studies on the particle sizes and material types that are actually in the environment.”

Earlier this year, the highest amounts of microplastics ever recorded were discovered in the Arctic Sea ice. On average, 12,000 pieces of microscopic particles were detected per liter of ice across five sample locations, with the research team identifying plastic packaging and increased shipping and fishing in the Arctic as the primary causes.