California is poised to issue the world鈥檚 first guidelines for microplastics in drinking water despite no data on how plentiful they are in the state, on how to test water for them and little research on their health risks.
The pieces of plastic 鈥� smaller than an ant, some so tiny they can be seen only with a microscope 鈥� have contaminated wildlife and human bodies through their .
Under a , California must require four years of testing for microplastics in drinking water, and the state must consider guidelines to help water providers and consumers determine what levels may be safe to drink.
Now the state Water Resources Control Board is blazing a trail to issue a preliminary health-based threshold and testing methods by July 1.
The state鈥檚 aim is to take a precautionary approach, moving to tackle potential threats posed by microplastics.
鈥淚s it too early to do something? No, it is actually a bit late.鈥�ROLF HALDEN, DIRECTOR OF ASU鈥橲 BIODESIGN CENTER FOR ENVIRONMENTAL HEALTH ENGINEERING
But there are big obstacles to such early action: Research into the consequences of ingesting tiny plastic fragments is still in its infancy. No one knows how widespread microplastics in California鈥檚 drinking water really are. to test for them. And no one knows what dose may be 鈥渟afe鈥� to consume, since the human health effects are .
California鈥檚 water regulators are pushing to close those gaps. 鈥淭o be honest, if the legislature hadn鈥檛 given us such an aggressive deadline, with rather high goals, this might not happen this year,鈥� said , a research scientist with the State Water Resources Control Board. 鈥淚t really is accelerating the field quite a bit.鈥�
, chemistry unit manager at the , which provides imported water to 19 million Californians, warns that monitoring drinking water for microplastics is going to be 鈥渧ery complicated and time consuming, and that鈥檚 why it鈥檚 expensive.鈥�
Developing a health guideline for microplastics is 鈥渁 tough one,鈥� said Razmik Manoukian, the Los Angeles Department of Water and Power鈥檚 director of water quality.鈥淏ut there鈥檚 a lot of studies worldwide done on plastic exposures 鈥� so it could be they can come out with a preliminary number.鈥�
Researchers applaud California鈥檚 efforts to move forward, even though they caution that drinking water is not thought to be the biggest source of microplastics people consume. People probably absorb more .
鈥淲e now know that we live in a soup of plastic that is getting ever denser. And we don鈥檛 seem to be changing our ways. And the contaminants, they live longer than we do, meaning that the soup will get thicker,鈥� said , director of the Biodesign Center for Environmental Health Engineering at Arizona State University.
鈥淪o is it too early to do something? No, it is actually a bit late.鈥�
Awash in microplastics
Microplastics have contaminated the environment and the bodies of animals : Ice cores , , , and in the Southern Ocean, fish and shellfish and even .
California banned microbeads in toiletries like facial scrubs and toothpaste . But sources of tiny plastic are still ubiquitous: Synthetic clothing sheds microplastics in that discharge into sewers, and crumbles into tiny particles. All of these particles can wind up in waterways that provide drinking water, such as the massive, .
of microplastic particles are floating on the surface of the world鈥檚 oceans, weighing at least . And that doesn鈥檛 include the unknown quantities in freshwater rivers and lakes, or the particles that have sunk into the oceans, washed ashore or been consumed by marine life.
While from pole to pole there鈥檚 been widespread study of the environment to figure out where microplastics have wound up, there鈥檚 been less research into their possible effects on people.
No government has developed a health-based threshold for microplastics in drinking water, according to the water board鈥檚 .
The health threshold won鈥檛 be an at this point; it鈥檚 unlikely to carry . Instead, it will probably be a preliminary guideline to help water providers and consumers assess the levels in their water, and it is likely to change with more research, Coffin said.
鈥淚t will be the world鈥檚 first health-based guidance value of any sort for microplastics formally recommended by a working group or government agency,鈥� he said. 鈥淭his will carry a lot of authority, even if it is just a preliminary guidance level.鈥�
California鈥檚 efforts took off when a constituent reached out to state , a Democrat from the La Ca帽ada Flintridge area, warning that plastic fibers in drinking water may contain toxic chemicals.
Despite opposition from the Metropolitan Water District and other water providers, the Legislature passed in 2018 calling for standardized testing methods and four years of monitoring statewide. The law also urged the water board to consider recommending a health threshold by . Another instructs the state鈥檚 Ocean Protection Council to develop a strategy for addressing microplastics in oceans.
鈥淭his will carry a lot of authority, even if it鈥檚 just a preliminary guidance level.鈥�SCOTT COFFIN, RESEARCH SCIENTIST AT STATE WATER RESOURCES CONTROL BOARD
The goal of the drinking water guideline is to help Californians understand the levels of microplastics detected in their water when the agencies start making the testing data public, which could happen as soon as next year.
鈥淭he question from the public (is), 鈥榃ell, what does that (level) mean?鈥� It鈥檚 never a satisfactory answer to say, 鈥楪eez, I don鈥檛 know,鈥欌�� said , water quality section manager of the Metropolitan Water District. 鈥淲e鈥檒l need to look to the state for guidance on that.鈥�
Now, an international team of researchers assembled by the water board and the , a public agency that has been studying waterway health since 1969, are scouring scientific literature for hints about the toxicity of microplastics.
Researchers have fed microplastics to rodents and reported and . Mice that ate microplastics had , and ones fed very high doses produced more abnormal sperm. Microplastics, which have , can pass through of rats and cause in mice.
The challenge is extrapolating the findings in lab animals to potential effects in people.
The in 2019 that there was too little evidence to understand the toxicity of microplastics, and 鈥渘o reliable information suggests it is a concern through drinking-water exposure.鈥�
Water providers who opposed California鈥檚 microplastics bill also said at the time that it was premature to set a guideline. 鈥淲ithout studying the effect exposure to microplastics has on the human body, there is no way to determine the impact of the varying levels of microplastics found in drinking water,鈥� the wrote in 2018.
But environmental health researchers in Europe against what they called this 鈥溾�榥o risk鈥� soundbite.鈥� Two scientists wrote in the journal that 鈥渓ogic does not allow the current knowledge gap鈥� to steer the bias towards a belief that 鈥榤icroplastics are safe.鈥欌��
鈥淲e can say with pretty high confidence that eating plastic and breathing in plastic is not beneficial,鈥� said , an environmental toxicologist at Oregon State University who is working with Coffin鈥檚 team.
鈥淲e鈥檙e pretty sure this is a problem. It鈥檚 just a matter of having enough data to say how much is too much.鈥�
Since the World Health Organization鈥檚 report, the number of toxicity studies about microplastics has roughly doubled, Coffin .
鈥淲e鈥檒l actually be able to say with some level of certainty whether or not this is an immediate issue for people鈥檚 health, or if it鈥檚 an issue that will arise down the road,鈥� he said.
鈥淲e can say with pretty high confidence that eating plastic鈥s not beneficial. We鈥檙e pretty sure this is a problem. It鈥檚 just a matter of having enough data to say how much is too much.鈥�SUSANNE BRANDER, ENVIRONMENTAL TOXICOLOGIST AT OREGON STATE UNIVERSITY
It鈥檚 the opposite approach to how drinking water is usually regulated. In most cases, state or federal water regulators of a contaminant is in the water, and research has already linked it to health effects in humans.
, a professor of aquatic ecology and water quality at Wageningen University in the Netherlands, said that California鈥檚 approach is warranted as an early risk assessment of an emerging contaminant.
鈥淚t is not that people do this (assessment) when it can be done. It is done when an answer is needed,鈥� said Koelmans, who has participated in California鈥檚 assessment of the health effects. 鈥淭hat makes us then take a more precautionary approach, to stay on the safe side.鈥�
The hunt for microplastics
Even as the state works to develop drinking water limits on microplastics, state officials know nothing about how plentiful they are in California鈥檚 water supply because testing has not started yet.
鈥淲e have been studying these things since 1959. And we still don鈥檛 have a standard method,鈥� Coffin said.
Until just a few years ago, many scientists peered through a microscope and sorted the particles by hand, Coffin said. 鈥淵ou squeeze the particle with tweezers, and you kind of have a guess if it鈥檚 plastic or not,鈥� he said. 鈥淰ery crude, honestly.鈥�
Now some labs stain the particles to make them easier to spot. They shine an infrared beam or laser at a particle and look for telltale wavelengths of light that it absorbs or bounces back to confirm it is plastic. Another way is to and analyze the gases.
The state assembled an international assortment of laboratories working to streamline these techniques and figure out which are the most cost-effective for testing drinking water, sediment, ocean water and fish tissue. They expect to reveal by July what tests water providers must use.
The is leading the effort, sending jars of water spiked with microplastics and other materials to more than two dozen labs to see if they can distinguish microplastics from other contaminants and accurately count particles.
鈥淭he sample sets that were put together for us were very interesting,鈥� said of the Metropolitan Water District, which is one of the labs. 鈥淭hey had rabbit hair in them. There was also cellulose fibers from toilet paper. There was a lot of different red herrings in there.鈥�
Slifko鈥檚 researchers filtered the water and then peered at the particles through microscopes. They picked out pieces of plastic with forceps, then put them on a petri dish lined with sticky tape to count them.
鈥淓ach of those samples took at least 120 hours per sample,鈥� Slifko said. 鈥淚n drinking water, it鈥檚 essentially looking for a pin in a haystack.鈥�
Another potential obstacle: contamination from plastic in the lab or researchers鈥� clothing, said , the Southern California water research project鈥檚 executive director.
鈥淲e actually have a lock on my laboratory. I do not have a key, and I run the place. Why? because I wear these polyester shirts! You鈥檙e not allowed in the lab with a polyester shirt,鈥� Weisberg said.
Stopping the flow
Some experts question whether focusing on drinking water is enough. , for instance, may be than tap water.
鈥淭hat health threat will not be addressed by just removing microplastics from drinking water, sadly,鈥� said Arizona State University鈥檚 Halden.
Ultimately, experts say, the solution will be to reduce the flow of plastics into the environment.
When your house is flooding, 鈥渢he first thing is you have to stop the pipe,鈥� Halden said. 鈥淲e have to stop the pipes that are flooding our environment, our food, our water, everything with these types of materials.鈥�
tend to . But sewage treatment plants can still release every year into waterways. They also can make their way back into the environment applied to crops.
California lawmakers are looking for ways to stop the flow of plastics with a package of bills announced last week. require new washing machines to be equipped with filters. But these bills may face an uphill battle. Last year, lawmakers after a fiery discussion aimed at restricting single-use plastic packaging and food products. that would have required filters in state laundry facilities died.
Testing water and setting a guideline is the first step.
鈥淚鈥檓 excited to see California鈥檚 influence on other states,鈥� said Oregon State鈥檚 Brander. 鈥淚t鈥檚 nice to see them taking the lead, and potentially setting a really good precedent going forward.鈥�
CalMatters is a nonprofit, nonpartisan media venture explaining California policies and politics.