Nitrate contamination in groundwater from fertilizer and animal manure is severe and getting worse for hundreds of thousands of residents in California’s Central Valley farming communities, according to a study released by researchers at the University of California, Davis.
Nearly 10% of the 2.6 million people living in the Tulare Lake Basin and Salinas Valley might be drinking nitrate-contaminated water. And if nothing is done to stem the problem nearly 80% of residents could be at risk of health and financial problems by 2050.
Rural residents are at greater risk because they depend on private wells, which are often shallower and not monitored to the same degree as public water sources. Current contamination likely came from nitrates introduced into the soil decades ago. That means even if nitrates were dramatically reduced today, groundwater would still remain polluted for decades to come.
According to the report, removing nitrates from large groundwater basins is extremely costly and not technically feasible. One relatively low-cost alternative is called “pump and fertilize:” Pulling nitrate-saturated water out of the ground and applying it to crops at the right time to ensure more complete nitrate uptake.
The safety of groundwater, which is the largest source of drinking water, is managed through the state’s Clean Water Act. But each source of contamination is handled differently, says Schroeter of the Central Coast water board, and agriculture is more lightly regulated than other industries.
For the 250 people living in San Jerardo the threat posed by nitrates is all too familiar. San Jerardo residents live in refurbished old barracks that have been converted into tidy homes.
Sonia Lopez moved into San Jerardo with her parents and five siblings in 1987. Something went wrong about nine years ago. Her skin became red and itchy. Her eyes burned. Her hair started falling out. Her family had the same symptoms, and she learned other San Jerardo residents were afflicted, too. While they did not find a cause for the cancers, Lopez and fellow resident Horacio Amezquita learned from health officials that nitrates in their well water had made their eyes red and their hair fall out.
The community also learned that its water had been contaminated with nitrates since at least 1990; over the years, three wells had been drilled and eventually were found to be tainted. Drinking water regulations limit nitrates to less than 45 parts per million. One well measured 106 ppm, or more than double the limit.
After repeatedly asking Monterey County officials to help, Lopez and Amezquita finally got a filtration system in 2006, and in 2010, the community connected to a new well two miles away that doesn’t need to be purified. The cost to Monterey County was about $5 million. San Jerardo residents used to pay about $25 a month for water; now, they pay as much as $130 a month.
“Our problem is going to be your problem,” she said. “It’s everyone’s problem.”
This article was produced by the Food & Environment Reporting Network, an independent and nonprofit investigative news organization.
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