California is blazing new environmental trails again. The State is set to become the first government in the world to issue a standard testing methodology and preliminary health assessment for microplastics in drinking water. The guidelines, originally scheduled for release this month but delayed due to the pandemic, will be published during the fall of 2021. There is considerable interest in the State Water Board’s (SWB’s) upcoming report, both within the water industry and the broader public. With plastic creeping into every facet of modern life, the SWB’s conclusions will likely lay the foundations for further research and policies.

Since the creation of the first synthetic ivory in 1869, plastic has become the invisible backbone of the modern world. Synthetic materials often serve as cheaper, more durable substitutes for rare and expensive natural resources like silk, ivory, and wood. Plastic production also facilitates many modern inventions and comforts, such as cars, computers, and phones. But the societal benefits of plastics in our day-to-day lives come at a cost as discarded plastic waste builds in our environment—and potentially in our drinking water. Increasingly, the prevalence of plastic in our world has bred concern about the long-term consequences of exposure to these man-made materials.

From pole-to-pole, studies have found trillions of plastic particles— weighing at least 10,000 tons—floating in oceanic surface waters. With so much plastic in the ocean, it is unsurprising that microplastics are found in the bodies of wildlife across the globe, from humpback whales in the North Sea to invertebrates in the Antarctic. Plastic pollution isn’t limited to the ocean either; according to a 2019 World Health Organization report, microplastics are also found in both bottled and tap water, as well as in food and air. So far, the research indicates that microplastics are ending up on our dinner plates and in our drinking glasses. What experts don’t know is the scope of microplastic pollution in drinking water or the impacts of microplastics on the human body.

Back in 2018, California state legislators passed Senate Bill 1422 to address growing concerns about the prevalence and toxicity of microplastics in drinking water. The bill identified four main goals for the SWB, starting with the need for a regulatory definition of a microplastic. The definition, which was published in July of 2019, defines microplastics based on the substance, state, and dimensions. Any solid polymeric materials with at least two dimensions between 1 and 5,000 micrometers is considered a microplastic. Using this clear definition as a guideline, the bill further directs the SWB to develop a standard testing method, preliminary health assessment, and laboratory accreditation process. The state must also create the framework for a four year drinking water study—all by the Fall of 2021.

The ambitious deadlines set forth by state legislators have presented researchers with both unique challenges and unique opportunities. On one hand, early action means that there is a paucity of research for the SWB to draw from. No one knows how widespread microplastics are in the state’s drinking water. There is no scientifically agreed upon standard testing method and there are very few robust health risk assessments. This puts a heavy research onus on the SWB as they work to complete their microplastic guidelines. “The State Water Board is shouldering a big responsibility,” said Dr. Scott Coffin, a research scientist at the State Water Board. “We’re doing a lot of the legwork for everyone else.” Both California and the rest of the country are looking to the SWB to provide a solid foundation for future microplastic policies.

On the other hand, research into the field of microplastics has boomed since the law went into effect. According to Coffin, the number of studies investigating the effects of microplastics in humans has tripled since 2018. “Without that deadline, we wouldn’t have been able to do a lot of things,” Coffin stated. “It fast-tracked contracts, pushed other projects down in priority for 40 different organizations. The concern is so high, right now [microplastics] are on the top.” 

Across the state, municipal water districts and private laboratories are setting aside other projects to work on microplastic research. The SWB partnered with 160 collaborators and 40 labs in 7 countries to assess microplastic testing methods. Ideally, the SWB hopes to find a cost and time efficient method that does not require highly specialized laboratory equipment or personnel. The analysis time for microplastic testing is also a key limiting factor. “We need a shortcut method,” Coffin explained, “we need something to tell us if we need to do the Full Monty.” From the initial list of candidate methods, the state has narrowed their scope to a handful that are currently undergoing targeted studies. But the state faced some unexpected hurdles when the outbreak of Covid-19 shut down many laboratories worldwide. “Samples sat on shelves…it really threw a huge wrench in the entire process,” Coffin explained. Despite the difficulties, the state is only a few months behind their initial goal. “The method we feel pretty good about, we’re very close to accreditation, [and] we’re pretty close to providing a preliminary health assessment—not too bad all things considered.”

The SWB will need to provide a preliminary health assessment by the fall. The assessment will not provide an enforceable standard or undergo the same rigorous process as state regulations. It is mostly intended to help water providers and customers interpret testing results once the mandated four-year study begins. Given the dearth of available research, the health-based threshold for microplastics will likely change as more data becomes available. A more comprehensive risk assessment is in the works and may be released within one to three years.

In the meantime, water agencies in California are preparing to carry out the statewide monitoring plan. And across the rest of the nation, other states are looking to California to provide a precedent for microplastic research and policies.