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  • Writer's pictureKyle Tianshi

California Senate Bill 1422: The Safe Drinking Water Act for Microplastics

Updated: Apr 9

Every plastic bag has a story. 

It begins in a plastic factory, where tubs of molten polyethylene are blown through a tube and cut into squares. The bags are shipped to your local grocery store, the shopping mall, your favorite restaurant. When you pick up takeout spaghetti and garlic bread from that restaurant, the bag will help you carry the food to the car and from the vehicle to your home, and then you’ll stow it away in a cabinet. The pasta is delicious, by the way. Twenty days later, you pull the bag back out to throw away scraps of the apple you just peeled. You toss the bag in the garbage disposal. Next Tuesday, as the garbage truck empties a week’s worth of waste into its dark recesses, the bag tumbles from the side of the black bin and escapes onto the street. Egged on by the wind, the bag escapes your neighborhood, floats under the freeway overpass, and finds itself in the creek alongside the local smelt fish. The water carries the bag out to sea. Your bag is already tattered when it arrives there, but the waves and rapid current break it into further pieces as it drifts further and further away from the coast.

Your bag is gone, right?

Not exactly. Along its journey, it’s been shedding small fragments of its body, little white bits of shrapnel often invisible to the human eyes.

Microplastics. Commonly defined as any plastic particle less than five millimeters in length, they’re absolutely everywhere. 

A 2019 study calculates that humans consume up to 50,000 microplastics every year. Severe estimates say that this is the equivalent of one credit card per week. 

Let’s go back to that plastic bag. As you untie the knot, it sprinkles microplastics across your pasta container lid the same way you shake parmesan across a plate of spaghetti. As the bag floats from the street across the highway into the river, scratching against the pavement and riled by winds, it leaves behind microplastics. And when it dissolves into the ocean waves, it releases tens of thousands, perhaps millions, more.

A 2023 study estimates that there may be up to 170 trillion microplastics in the ocean, and describes this pollution as a “growing plastic smog.” Another researcher put it as a “thickening plastic soup.” While scientists currently don’t have conclusive results about their possible health impacts, current research indicates that they are likely harmful. Microplastics have been found to absorb hazardous substances like heavy metals, persistent organic pollutants (POPs), polybrominated diphenyl ethers (PBDEs), and more. They also may accumulate in narrow passages in the human body, resulting in blockages, inflammation, and other adverse health effects.

Why do we still not know the exact effects of microplastics, even though they’re everywhere? The reason for this is because they’re everywhere. In fact, scientists can’t find a control group of people who have never been exposed to microplastics. This is shocking in and of itself. There are very few things that every human has experienced or known. The sun. Gravity. Eating food. Sleep. And now among those things — microplastics. Despite this, many governments haven’t yet implemented policies to address microplastic contamination.

California is now the first government in the world to require the testing of microplastics in drinking water. Senate Bill 1422 required the State Water Resources Control Board to adopt a definition of microplastics by July 2020 and to develop a standard methodology for the detection of microplastics in drinking water by July 2021. 

In November 2021, the State Water Board published the Microplastics in Drinking Water Policy Handbook, which details some of the progress they’ve made. The document defines “nanoplastics” as any particle between 1 nanometer (the size of ten atoms) and 100 microns (the thickness of an average human hair). “Large microplastics” are any particle between 100 microns and 2.5 centimeters (the size of a peanut). These size comparisons demonstrate the vast disparities in the size and shape of microplastics. With enough degradation, pieces of your plastic bag might even reach the nanoplastic level.

The Board also established two primary methods for the detection of microplastics: Raman spectroscopy and infrared spectroscopy. Both these techniques use similar approaches to identify plastics. In Raman spectroscopy, high-intensity light is used to excite the molecules within individual particles. The Raman scattered light that is returned can be used to analyze the particle’s chemical composition. In infrared spectroscopy, a machine measures the vibration of molecules through infrared light. 

While both these methods are effective at accurately identifying microplastics, spectroscopy still has some distinct disadvantages. The procedure uses highly complex and expensive devices that require trained personnel to operate, making it inapplicable to many scenarios where microplastic detection is needed. As a result, the California Water Board is considering “surrogate methods” such as flow cytometry, turbidity, and total suspended solids to more cheaply and efficiently detect microplastics while maintaining a high degree of accuracy.

Lastly, the California Water Board has begun the process of monitoring plastic content in drinking water across the state. They’ve been accomplishing this by partnering with accredited labs to develop a comprehensive testing process. Now, thirty Californian water providers will be required to perform quarterly tests on their source water, beginning this fall.

All this is a fantastic start for the first government in the world to pass legislation surrounding microplastics. It’s also the first standardized drinking water monitoring plan for microplastics. But a lot more needs to be done, and some fear that we might already be too late.

Senate Bill 1422 does not discuss the filtration of microplastics from drinking water. Such a topic needs to be addressed in future pieces of legislation or independently researched by the Water Board. Other researchers are excited about California’s progress, but many are concerned that microplastics in drinking water aren’t even the biggest issue. Humans inhale just as many plastics through the air. 

With our earth looking more and more like plastic smog or a plastic soup, the question is not only how to remove microplastics from existing water sources, but also how to prevent future plastics from being created and distributed. Of course, there’s Senate Bill 54, which requires all packaging in California to be recyclable or compostable by 2032. And all Californians are familiar with Senate Bill 270, the policy that bans single-use plastic bags at stores. 

Independent innovator Boyan Slat constructed his own solution to cutting off plastic pollution in oceans through a cleanup system called the Interceptor. When he discovered that rivers are the primary source of ocean plastic pollution, he designed an autonomous, solar-powered solution to intercept all downstream river contaminants before they enter the ocean. Interceptors have been placed in rivers across the world, and October 2022 saw the grand opening of the newest boat in Ballona Creek, Los Angeles. The Ocean Cleanup, Slat’s non-profit organization, aims to clean up 90% of floating ocean plastic pollution.

Non-profits, independent inventors, and government policymakers are all pooling their energy and expertise to address the issue of plastic and microplastic contamination in our waters. Some good news is that recent efforts have removed record amounts of plastics from high-density areas of contamination like the Great Pacific Garbage Patch. 

If all goes well, let’s see what changes we’ll have to make to the story of your plastic bag:

In ten years, a ship will scoop the bag from the middle of the Pacific alongside millions of tons of other plastic waste.

In fifteen, your bag will be caught at the mouth of the river by an interceptor before it even gets lost at sea. 

And in twenty, the bag won’t be made out of plastic at all. 


Becker, Rachel. “California Approves Microplastics Testing of Drinking Water Sources.” CalMatters, 7 Sept. 2022.,

Bill Text - SB-54 Solid Waste: Reporting, Packaging, and Plastic Food Service Ware. Accessed 23 July 2023.

Bill Text - SB-270 Solid Waste: Single-Use Carryout Bags. Accessed 23 July 2023.

Bill Text - SB-1422 California Safe Drinking Water Act: Microplastics. Accessed 23 July 2023.

Cox, Kieran D., et al. “Human Consumption of Microplastics.” Environmental Science & Technology, vol. 53, no. 12, June 2019, pp. 7068–74. (Crossref),

Eriksen, Marcus, et al. “A Growing Plastic Smog, Now Estimated to Be over 170 Trillion Plastic Particles Afloat in the World’s Oceans—Urgent Solutions Required.” PLOS ONE, vol. 18, no. 3, Mar. 2023, p. e0281596. PLoS Journals,

Gruber, Elisabeth S., et al. “To Waste or Not to Waste: Questioning Potential Health Risks of Micro- and Nanoplastics with a Focus on Their Ingestion and Potential Carcinogenicity.” Exposure and Health, vol. 15, no. 1, Mar. 2023, pp. 33–51. Springer Link,

US Department of Commerce, National Oceanic and Atmospheric Administration. What Are Microplastics? Accessed 23 July 2023.

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