John Metcalfe is CityLab’s Bay Area bureau chief, based in Oakland. His coverage focuses on climate change and the science of cities.
Microplastics contaminate the water on a massive scale.
They’re in the oceans, in the Great Lakes, and now it turns out they’re fouling the Chesapeake Bay—microplastics, the remnants of unrecycled products that are damning the world’s water to seemingly eternal pollution.
The presence of microplastics—from broken-up containers to ingredients in bathroom products—has been established in four Bay tributaries by researchers at the University of Maryland, NOAA, and elsewhere. “Microplastics were found in all but one of 60 samples, with concentrations ranging over 3 orders of magnitude (<1.0 to >560 g/km2),” they write in Environmental Science and Technology. “Concentrations demonstrated statistically significant positive correlations with population density and proportion of urban/suburban development within watersheds.”
One can deduce that with more growth around Baltimore and Washington, D.C., we can expect to see yet more microplastics. See, and maybe eat, too, as scientists recently discovered the stuff’s being consumed by plankton and passed up the food chain. That’s bad news for marine animals, which can starve on the nutrientless substances or die of stomach obstructions, and possibly for humans, as plastics leach chemicals into fish with unknown impacts on our health. (They might also affect that treasured Chesapeake delicacy, blue crabs, as crabs both eat and breathe in microplastics.)
The Chesapeake Bay Program interviewed the study’s lead author, the University of Maryland’s Lance Yonkos, to determine the sources and ramifications of microplastics. Here’s an excerpt:
“We have many of the prime sources for creating and introducing microplastics to aquatic environments,” Yonkos said. Roads are a main contributor because they promote physical degradation of plastics and provide easy transport via storm drains to Bay tributaries. Yonkos listed wastewater treatment plant effluent and substantial shipping traffic.
As plastic fragments become smaller, a greater number of animals are able to swallow them—as exemplified by the recent case of a whale killed by a shard from a DVD case. When these materials break down enough reach the level of microplastics, even filter feeders like oysters can consume them….
But, the science isn’t clear yet on whether microplastics represent a serious environmental or human health concern.
“Since we don’t really know yet, it is a little disconcerting to think that most of the plastics we have created over the past 70 years are still in the environment,” Yonkos said.
In the lab, the Bay program’s Will Parson took clinical, close-up shots of some of the plastic the researchers netted. It’s a fascinating and grim photo series: The particles mimic polluted crystals, shrunken tumors, and nasty viruses under a microscope. Have a look, and for the full array head to Flickr: