ANNAPOLIS — Researchers who went looking for microplastics in the Chesapeake Bay watershed found them everywhere they checked, from the Susquehanna River’s headwaters in New York to the mouth of the Bay in Virginia.
A report released Nov. 10 by the nonprofit Environment America and its Pennsylvania affiliate, the PennEnvironment Research and Policy Center, said all 90 water samples collected at 15 sites contained the particles. The sites were in the Bay and selected tributaries in Maryland, Virginia, Pennsylvania, New York and Washington, D.C.
The finding describes the places that were sampled. It is not a measurement of all Bay water, and the report’s headline figures count how often each kind of plastic turned up, not how much of it there was.
Microplastics are plastic pieces smaller than 5 millimeters. Most are what is left when bottles, bags, packaging and synthetic clothing break down; some are manufactured small. The report sorted what it found into four types, according to accounts of the findings by WYPR and other outlets that covered its release in Baltimore:
- Microfibers, shed mainly by clothing and textiles: 100% of sites
- Microfragments, from harder plastics: 93% of sites
- Microfilm, from bags and flexible packaging: 47% of sites
- Microbeads: 27% of sites
Maryland banned the sale of cosmetic products containing microbeads in 2015. The Baltimore Banner reported that beads appeared at only one of the Maryland test sites.
The Chesapeake Bay Foundation, which circulated the report, used it to call for state action. Gussie Maguire, the foundation’s Maryland science manager, said the study confirms what many suspected about the amount of plastic in the watershed, from visible trash on beaches to particles too small to see. “Microplastics are bad news for the Chesapeake Bay,” Maguire said. She urged Maryland to limit single-use plastics and pay for programs that reduce litter.
The foundation’s statement also said the particles can leach toxins and damage DNA in ecosystems and in people. Those are the advocacy group’s characterizations; the Environment America study tested water for the presence of plastic and did not measure health effects.
The results fit a pattern in earlier, independent research. A U.S. Geological Survey effort cited by the federal-state Chesapeake Bay Program found microplastics in every sample taken at its nontidal monitoring stations in the watershed, and a Bay Program science panel has flagged wastewater plants, which were not built to filter the particles, as one pathway. Scientists have also found that tidal marshes trap microplastics, turning some of the Bay’s most productive habitat into collection points.
For Southern Maryland, the report bears on waters that support the region’s crab, oyster and rockfish harvests and that border all three counties: the Patuxent and Potomac rivers and the Bay itself. Concern about the particles has not been limited to waterways. In September, a separate study that found microplastics in baby food prompted calls for regulation.
