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Researchers at University of California, Berkeley found that the drinking water at a state prison and its surrounding rural areas contained potentially dangerous levels of arsenic in recent years.

The study, published last week in Environmental Health Perspectives, looked at two decades worth of water quality data from Kern Valley State Prison and three nearby Central Valley communities — Allensworth, McFarland and Delano.

All groundwater aquifers examined in the study had several incidents of unhealthy amounts of naturally occurring arsenic in the water, sometimes surpassing federal contamination levels for months or years.

Arsenic is a naturally occurring element found in soil, water, air and living things. Unhealthy levels of arsenic are more commonly found in groundwater in the western portion of the country, according to the EPA. (Image via Freepik)

Though all communities are now meeting federal arsenic standards, researchers say they found “persistent water injustices” on both sides of prison walls — some incidents were not officially recognized as a violation by California’s Division of Drinking Water, and others occurred even after the communities received state funding for water treatment, according to the study.

“We conducted this study, in part, to try and better understand how disaggregated water quality data could be used to identify historic exposures to drinking water contaminants among incarcerated and non-incarcerated populations sharing similar groundwater,” said the study’s senior author Alasdair Cohen, an assistant professor of Virginia Tech.

In 2001, the federal Environmental Protection Agency initiated stricter regulatory limits on arsenic levels in water, replacing the previous standard of 50 parts per billion (ppb) to 10 pbb. The standard was set after chronic exposure to the mineral was linked to various cancers, cardiovascular disease and diabetes, among other serious health effects.

Arsenic is everywhere

Arsenic is an element found in soil, water, air and living things, and can be released into the environment through natural activities like erosion and forest fires, or human activity like farming and mining. According to the EPA, unhealthy levels of arsenic are more commonly found in groundwater in the western portion of the country.

Kern Valley State Prison opened its doors in 2005, though a $6 million water treatment for arsenic remediation was not built for another eight years, said first author and graduate student of UC Berkeley, Jenny Rempel.

“To our knowledge, Kern Valley State Prison was built without arsenic remediation plans, even though some of the early water quality data suggested the system would soon be out of compliance with the new arsenic standard,” Rempel said. “That meant thousands of people were likely drinking contaminated water until the treatment plant came online.”

The prison’s average arsenic levels in its drinking water were around 20 ppb until the treatment plant was installed, through arsenic levels still occasionally rose to above 20 pbb from 2017 to 2019, according to the study.

“To our knowledge, Kern Valley State Prison was built without arsenic remediation plans. … That meant thousands of people were likely drinking contaminated water until the treatment plant came online.”

Jenny Rempel, study co-author

Researchers say there is a pattern of rural and low-income areas having less access to clean drinking water across the country, in part because of historical disinvestment and lack of regulation enforcement. Cohen said low-income communities are likely to miss water treatment, provision and maintenance because this funding comes from the residents themselves.

“This is part of the reason why people living in lower income rural communities in the U.S. tend to have disproportionately higher exposures to contaminated drinking water, and why, once some systems are out of compliance with EPA regulations, they can remain so for some time,” Cohen said.

Delano, with a population of 50,000, was the largest community sampled in the study, and rarely exceeded 10 ppb of arsenic after new treatment facilities and wells were built in 2013. But in the 600-person community of Allensworth, which doesn’t have a water treatment facility, the town utilizes subsidized bottled water when their two wells of groundwater exceed contamination levels.

Seeking a low-cost treatment solution

Rempel said there is a need for new technology that can provide arsenic-safe water efficiently.

“California has increased its investments in drinking water solutions for low-income communities,” Rempel said, “But to really deliver on the promise of the human right to water, we need to establish adequate technical assistance and other creative approaches to ensure that communities are able to successfully operate treatment systems in the long term.”

Engineers at UC Berkeley are setting up test sites in Allensworth to create a low-cost, simple arsenic treatment solution for the rural communities who cannot afford to install the current treatment systems.

Dennis Hutson works on his farm in Allensworth in the southern San Joaquin Valley on June 16, 2022. The 600-person community, which doesn’t have a water treatment facility, uses bottled water when their two wells of groundwater exceed contamination levels. (Photo by Adam Lau/Berkeley Engineering)

An estimated 300,000 Californians are exposed to dangerous levels of arsenic in their drinking water, said Ashok Gadgil, professor of civil and environmental engineering at UC Berkeley.

And as drought and extreme heat dries up California’s surface water, more communities will have to dig into groundwater sources for drinking water, and may run into older, deeper aquifers that are more contaminated. Engineers are hoping to reframe what local drinking water can be.

“For the first time, we’ll be treating groundwater with high levels of arsenic at a price local people can afford and in a way that they can operate,” said Gadgil.