Microplastics – plastic debris measuring less than 5 millimeters – are an increasing water quality concern. Entering the water as industrial microbeads or as larger plastic litter that degrade into small pellets, microplastics come from a variety of consumer products.
Microbeads are used in exfoliating agents, cosmetic washes and large-scale cleaning processes. Microplastics are used pharmaceutically for efficient drug delivery to affected sites in patients’ bodies and by textile companies to create artificial fibers.
Part of their appeal to hygienic and medical interests is their tendency to absorb surrounding chemicals and later release them. This quality makes microplastics ideal as small commercial sponges, but especially dangerous as water contaminants, potentially carrying harmful chemicals through the food chain as they are ingested.
Challenges of Removing Microplastics
Microplastics are highly mobile, distributing easily and widely throughout surface waters and sediments. As primary and secondary microplastics continue degrading from UV light, microbes and erosion, their smaller size further complicates filtration efforts.
Additionally, these particles are usually composed of polyethylene or polypropylene plastic, which take thousands of years to naturally biodegrade. Consequently, most water treatment plants are unable to remove them, as they require prohibitively high temperatures to fully break microplastics down. Health effects from consumption are currently under investigation.
Many advocacy groups have published lists of products containing microbeads in an effort to curb the purchasing, and therefore the pollution, of microbeads.
The U.S. Environmental Protection Agency (EPA) regulates microbeads in industrial, but not domestic, wastewater. The U.S. Food and Drug Administration (FDA) labels microbeads in cosmetics, but lacks the authority to outright ban them.
A new federal law phases out the use of microbeads beginning in July 2017. Dozens of states have some kind of laws regulating microplastics, nine of which preceded the federal microbead ban.
California has the strictest microbead limitation, not leaving room for selling products with biodegradable microbeads.
Microplastics in California Water
A 2015 sampling of San Francisco Bay by the San Francisco Estuary Institute’s Regional Monitoring Program (RMP) found microplastics levels to be higher than those reported in the Great Lakes, Chesapeake Bay and Salish Sea, which make up some of the major existing data on microplastic concentrations in US waters.
It is believed the high microplastic levels are due to the Bay Area’s high population density and because water conservation measures increase the ratio of plastics to water.
The RMP in 2016 will release a recommended plan for the next 3-5 years aiming to reduce microplastics in the San Francisco Bay through source control.