California Leads the World in Testing Drinking Water for Microplastics

By: - September 27, 2022 12:00 am

Plastic bottles and other waste lie washed up along the Delaware River in Philadelphia. Degrading plastic pollution has contaminated the world’s drinking water with microplastics. Jonathan Elderfield/The Associated Press

You are drinking microplastics.

Miniscule fragments of deteriorated plastic from bottles, bags and other products are in the deepest depths of the ocean, in the Antarctic and Arctic, and in countless rivers and lakes. Now, these specks — some less than 5 millimeters and others only visible by microscopes — are in the drinking water of millions of Americans.

While there is still more research needed on the health effects of ingesting these particles, California has taken the first steps to better understand the extent to which microplastics have infiltrated its drinking water by launching a statewide testing apparatus.

This initiative is not just unique within the United States. California is the first government entity in the world to test its drinking water for microplastics, setting a global bar that could inspire a wave of new research on a pollution that increasingly worries experts.

Before it can begin to remove microplastics, California officials must first understand how much is in drinking water and freshwater sources, said Randy Barnard, the technical operations section chief for the Division of Drinking Water at the California State Water Resources Control Board.

“This is the tip of the iceberg,” he said. “Somebody’s got to take the first step. This is going to answer some questions and raise more questions, which is good.”

Microplastics, like many other contaminants, are everywhere — in the air, our food and our water, said Susanne Brander, an environmental toxicologist and an associate professor at Oregon State University. They don’t decay naturally, but instead break down into smaller and smaller pieces. She said it’s important that the state methodically work throughits “cutting-edge” testingand explain to people what’s in their water.

“Even if it doesn’t seem like a problem now, it’s going to get worse if we don’t do something,” she said. “Plastic production is projected to increase exponentially, and that means we get exposed to more of these little particles.”

In recent years, Brander has been part of a group of researchers from around the world that helped California define microplastics, standardize methods by which local water officials can test for microplastics — considering different sizes, materials and colors — and set thresholds for acceptable levels of microplastics in drinking water.


Over the next five years, many regional water systems throughout California will voluntarily report to the state the microplastic levels they detect in drinking water. To gather consistent data, the state is training county officials on procedures and methods for testing their water.

After state and local officials work out kinks in the testing methods and analyze initial data, water utilities will start testing their water sources for microplastics — all building toward a statewide, mandatory effort to test and analyze water for the particles. Only after the next several years would the state consider creating methods to filter microplastics out of water.

The state water board’s effort was born out of a 2018 law that directed state water providers to create a standardized method for testing drinking water and freshwater sources for microplastics. That legislation, which Democratic state Sen. Anthony Portantino sponsored, was paired with another measure that set up monitoring and testing of microplastics in the ocean off California’s coast. A state report noted that globally, an estimated 11 million metric tons of plastic enter the ocean each year, which could triple by 2040 without intervention.

The legislation passed with near unanimous support, with only three Republicans in the legislature voting against the measures.

The Plastics Industry Association, a lobbying organization, did not respond to a request for comment.

Releasing public data will help the problem of microplastics evolve from a theoretical challenge to one that is real for Californians, said Portantino.

“We’ll have real information to say to the public, ‘By the way, do you know this is what’s in your water, and do you know this is what it’s going to take to get it out of your water?’” he said in an interview. “Then, we can put in place the policies to screen, remove, treat — whatever the data suggests we should do, we’ll have science on our side, not just theory.”

While he has yet to hear from lawmakers in other states about his microplastic legislation, Portantino predicted that once California begins releasing data, other states will be inspired to follow the Golden State’s “pragmatic, science-based, long-term strategy.”

California has, for years, attempted to curb plastic in the state. In 2015, the state banned plastic microbeads in personal care products, such as toothpaste and facial scrubs, while last year, the state prohibited the use of single-use plastic utensils and condiment packages from restaurants unless requested by the customer. The state hopes to reduce single-use plastic packaging by 25% by 2032.

While California state and regional water officials test water for microplastics, they will continue to rely on the scientific community to study the human health and environmental impacts.

That science is still lacking, said Miho Ligare, plastic pollution policy manager for the Surfrider Foundation, a California-based environmental advocacy organization that supported the 2018 legislation. But initial research has been worrisome, she said.

“Microplastics are detrimental to the environment and human health,” she said. “They are leaching into the water. You’re actually drinking toxins.”

Worldwide, researchers have discovered microplastics in everything from seafood to plants to human infants’ stool. Studies show that microplastics have caused brain damage and behavioral disorders in fish, hinder growth in zooplankton, and damage reproduction rates and cause intestinal inflammation in mice. Testing on human tissue, scientists have found that microplastics can lead to cell degradation.

But many studies acknowledge that more research is required to determine the toxic health effects of these particles.

Microplastics are abundant and airborne, said Sherri Mason, director of sustainability at Penn State Erie’s The Behrend College. Microplastic pollution even comes from microfibers shed from clothing made from synthetic materials, she said, making microplastics ubiquitous — and hard to rein in.

States are not going to be able to filter their way out of the microplastic problem, said Mason, who published an article in American Scientist in 2019 that found widespread microplastic pollution in the Great Lakes — a major source of freshwater for the region. That would place too heavy a burden on public infrastructure, which already is underfunded, she said.

“It’s not like water treatment isn’t doing their job. They’re doing their job well,” she said. “But they weren’t designed for microplastics and atmospheric fallout.” 

Indeed, removing microplastics from the ocean or freshwater sources is difficult, said Jackie Nuñez, advocacy and engagement manager at the Plastic Pollution Coalition, a group that collaborates with an alliance of organizations and businesses to reduce plastic waste.

The better approach is to prevent plastic from reaching water in the first place, she said in a phone interview as she cleaned up plastic waste around Yosemite National Park for the annual Yosemite Facelift volunteer event. Companies should stop selling single-use plastic products, she said, while consumers should buy products that are more sustainable and less wasteful.

“Plastic is not going away,” she said. “It just gets smaller and smaller. We can’t filter and recycle our way out of it.”

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Matt Vasilogambros
Matt Vasilogambros

Matt Vasilogambros covers voting rights, gun laws and Western climate policy for Stateline. He lives in San Diego, California.