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SACRAMENTO, Calif., July 6, 2024
<em>A new study suggests current arsenic levels in California's drinking water may pose risks to infant health.</em>
<ul>
<li>Study links low-level arsenic exposure to adverse birth outcomes.</li>
<li>Experts urge reevaluation of the EPA's arsenic standards.</li>
<li>California acknowledges the need for more protective water quality levels.</li>
</ul>
The presence of **arsenic in California's drinking water**, even at levels deemed safe by the EPA, is under increased scrutiny due to potential links to adverse birth outcomes.
California's drinking water is facing renewed examination as experts suggest that current safety advisories may not be protective enough. A nationwide study led by Columbia University researchers indicates that parts of the state have arsenic levels in public drinking water exceeding 5 micrograms per liter.
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According to a nationwide study led by researchers at Columbia University, parts of California have levels of arsenic in public drinking water higher than 5 micrograms per liter.
María José López/Europa Press Via Ap
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While the Environmental Protection Agency (EPA) deems arsenic levels safe at 10 micrograms per liter or less, the study uncovered health risks even at these lower concentrations. Consumption of water with arsenic levels at 10 micrograms or less correlated with a higher incidence of preterm births, lower birth weights, and babies born smaller than expected for their gestational age.
<h3>Broader Health Concerns</h3>
Cardiovascular disease, type 2 diabetes, and heightened cancer risks have also been linked to low-level arsenic exposure in other research.
**What level of arsenic in drinking water is considered dangerous?** The EPA currently maintains that levels of arsenic in drinking water are safe at 10 micrograms per liter or less, but studies have found health risks associated with even lower levels.
The EPA acknowledges that while the ideal level of arsenic in drinking water would be zero, "technical limitations" and cost make this unattainable for water systems. The current maximum contaminant level is based on a "health risk reduction and cost analysis," balancing public health concerns with feasible targets for water service providers.
<h3>California's Stance</h3>
The California State Water Resources Control Board stated that California already has some of the strictest water standards in the nation. They also acknowledged that this new study reinforces the need to revise the maximum contaminant level to better protect human health, particularly infant development, and that the state is actively addressing this issue.
Sacramento County, identified as one of the regions with elevated arsenic levels, reports that the City of Sacramento Department of Utilities "closely monitors water quality and is committed to meeting or exceeding all state and federal drinking water standards, including those for arsenic." The city's most recent Consumer Confidence Report indicated an average arsenic level of 2.3 micrograms per liter, below the EPA's limit, with groundwater levels ranging from non-detectable to 4.7 micrograms per liter.
"The City of Sacramento's drinking water meets or exceeds all federal and California state water quality standards," the city's Department of Utilities affirmed, adding its support for California's science-based approach to setting water quality standards.
The Sacramento County Water Agency stated, "We are in compliance with the state's standards. We do not dictate the guidelines." Their 2024 Consumer Confidence Report revealed that arsenic levels in Northgate and Southwest Tract reached 5 micrograms per liter, while East Walnut Grove exceeded EPA guidance, ranging from non-detectable to 11 micrograms per liter.
Merced County also appeared to have higher levels of arsenic in drinking water, according to the study's map. A public information officer for the city of Merced stated that the city's drinking water is "routinely tested and remains in compliance with all state and federal safety standards, including those for arsenic." They added, "We monitor over 250 contaminants and collect thousands of samples annually to ensure water quality," also stating that they "take emerging health research seriously and remain committed to providing safe, clean water to our residents."
Arsenic is a natural element found in soils, sediments, and groundwater. Its presence in drinking water systems can vary due to natural geology, human activities, and irrigation practices.
<h2>Why California's Water?</h2>
Many Californian community water systems depend on groundwater naturally high in arsenic, according to Bethany O'Shea, a professor in the environmental and ocean sciences department at the University of San Diego. Even with treatment, detectable levels of arsenic may remain in the water supply.
Janet Hering, former director of the Swiss Federal Institute of Aquatic Science and Technology, attributed California's high arsenic levels to "geologic sources," with Los Angeles' water supply influenced by "inputs of geothermal water at Hot Creek in Owens Valley."
Peggy A. O'Day, a professor at the University of California Merced, explained that in the Central Valley, arsenic originates in minerals within rocks of the Sierra Nevada foothills. Weathering and erosion transport these minerals to the valley, where they are deposited as sediments. Mineral alteration and dissolution can then release arsenic into the groundwater.
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A map showing the levels of arsenic in drinking water in different locations.
Uncredited/JAMA Network
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O'Shea also noted that arsenic can be found in privately supplied water from wells, with elevated levels in wells across states like Maine, New Hampshire, and Vermont. "Similar birth outcome risks may exist for people drinking from private wells containing arsenic," she warned, emphasizing the need for more research on the health risks of even small concentrations of arsenic in all types of drinking water.
<h2>Potential Solutions</h2>
Experts generally agree that the current maximum contaminant level for arsenic should be reevaluated.
"The important finding of this study is that even those small concentrations of arsenic remaining may be harmful, suggesting that a lower water standard may be effective," O'Shea stated.
Denmark and some U.S. states, including New Jersey and New Hampshire, have already set water standards at 5 micrograms per liter, lower than the EPA's 10 microgram per liter level. "Setting that goal of zero as a standard—or even lowering the standard by half, to 5 micrograms per liter—may help alleviate health risks," O'Shea suggested.
O'Day believes the study supports a "history of evidence" indicating that the current arsenic level "may not provide a sufficient level of protection from adverse health impacts for all segments of the population." She advocates for reviewing and updating federal drinking water standards based on new scientific information.
O'Day acknowledged that lowering the maximum contaminant level is "a long process and does not necessarily ensure that public water suppliers have the resources to meet it without an undue cost burden on their customers." She emphasized that "more funding needs to be directed towards rural and underserved communities to improve their infrastructure and testing to provide safe drinking water that meets health-based standards for arsenic, lead and other contaminants."
Hering cautioned that "legally, lowering the [maximum contaminant level] has to reflect practical considerations and economic feasibility," suggesting that prioritizing potential adverse exposures and considering other possible contaminants alongside arsenic makes sense.