Nitrate-tainted drinking water plagues California farmworker towns, study shows

California officials have long known that pollution from the state’s $50 billion farming industry fouls drinking water sources in poor Latino communities where many toil as farmworkers. Now a review of state and federal data shows the problem is getting worse. More than 5 million people in California’s largely Latino communities have nitrate levels in their drinking water at or above federal standards, according to an analysis by the Environmental Working Group released Wednesday.

Nitrate occurs naturally in ground and surface water, but it can reach dangerous levels in drinking water when animal manure and chemical fertilizers applied to crops seep into the water source. When California passed a measure last year to upgrade water systems and reduce nitrate and other contaminants, state officials acknowledged that more than a million residents lacked safe drinking water. 

The EWG report reviewed nitrate tests over a longer time frame than the state’s analysis because nitrate levels can vary from year to year and reveal trends, said Anne Weir Schechinger, EWG senior economic analyst and author of the report. 

Nitrate is among California’s most widespread drinking water contaminants. UC-Davis researchers predicted nearly a decade ago, in a report commissioned by the state, that nitrate-tainted water problems would increase as fertilizer applied years ago leeches into aquifers. 

“Nitrate levels have been going up over time for many Latino communities,” Schechinger said. “Not only are these communities using potentially unsafe water, but also nitrate levels in the water are getting worse.”

In the San Joaquin Valley — the nation’s most productive agricultural region — nitrate levels rose between 2003 and 2017 in 65 percent of water systems, serving nearly 956,000 people. The average income for valley communities with nitrate-tainted water is close to $50,000, less than half the state’s average. Most troubling, the higher the water system’s contamination levels, the more likely it was to serve mostly Latino communities. 

Nitrate exposure is most commonly associated with blue baby syndrome, a potentially deadly disorder caused by low oxygen levels. It has also been linked to an increased risk of cancer.

“While California has made significant advances in recent years to promote access to safe, clean, and affordable drinking water for all Californians, this report shows we still have much further to go, especially for rural, low-income families and communities of color,” said Susana De Anda, cofounder and executive director of the Community Water Center, a drinking water advocacy group in California. The state must enact strong nitrate regulatory programs, particularly on two of the most common sources of nitrate contamination, irrigated agriculture and animal operations, she added.

Scientists first reported in 2011 that the people most affected by California’s agricultural pollution were Latinos living in the San Joaquin Valley. “Importantly, this trend was strongest in smaller communities, which are generally more vulnerable,” said Carolina Balazs, who led the study while a researcher at the University of California-Berkeley. 

“That these findings persist, nearly one decade later, is particularly troubling,” said Balazs, now a research scientist at the state’s Office of Environmental Health Hazard Assessment. “They underscore the persistent nature of groundwater contamination, the chronic nature of exposure, and the continual coping costs communities must face.”

The state’s inability to provide affected communities with safe drinking water has long forced poor residents of farmworker communities to pay for bottled water in addition to bills for tap water that’s not fit to drink. In recent years, community groups like Self-Help Enterprises have stepped in to provide families in need with safe drinking water. But when the coronavirus pandemic hit, people found themselves driving from town to town in search of grocery stores that hadn’t been raided by panicked shoppers, as FERN reported in April.

“That Latinos and lower-income communities shoulder a greater burden of nitrate exposure is particularly problematic, given the cumulative stressors communities of color face and the long-term health impacts that people subsequently suffer,” Balazs said.