Freshwater tidal marshes, critical for wildlife and coastal protection, are now serving as microplastic catch basins, according to a team of researchers at Penn State. They recently found that these marshes trap large amounts of diverse plastics, with concentrations and ecological risks increasing downstream.
The study, available online now ahead of publication in December issue of the journal Marine Pollution Bulletin, found that the most hazardous polymers - such as the large molecules found in single-use plastics - are posing significant environmental dangers.
"Estuaries and the tidal marshes at their fringes are highly productive and diverse habitats because they are areas where fresh and saltwater mix," said Nathaniel Warner, associate professor of environmental engineering and corresponding author. "The accumulation of plastic and the estimated toxicity associated with it could reduce the overall productivity of estuaries and threaten the health of fisheries and their economic viability."
In this study, the researchers analyzed sediment from the John Heinz National Wildlife Refuge outside of Philadelphia, the largest remaining freshwater tidal marsh in Pennsylvania. They identified 4,590 microplastic particles and 29 polymer types, with polypropylene, polyurethane and tire rubber being most common.
