California’s agriculture boom means nitrate-tainted water for at least 212,000 people.
Farm workers harvest romaine lettuce in California’s Salinas Valley. Nancy Nehring/iStock
In two of California’s most productive farming regions, at least 212,000 people rely on water that’s routinely unsafe to drink, with levels of a toxin above its federal limit. And even if the pollution source could be stopped tomorrow, these communities—representing a population more than twice as large as that of Flint, Michigan— would endure the effects of past practices for decades. That’s the takeaway of a major new assessment by researchers at the University of California-Davis.
The toxin in question is nitrate, which leaches into aquifers when farmers apply synthetic nitrogen fertilizers or large amounts of manure to fortify soil. Although probably not as ruinous as lead, the contaminant that fouled Flint’s water, nitrate isn’t something you want to be gulping down on a daily basis. Nitrate-laced water has been linked to a range of health problems, including birth defects, blood problems in babies, and cancers of the ovaries and thyroid.
According to the Davis report, nitrate takes a leisurely path from farm soil into the underground water sources that provide both irrigation and drinking water to these regions—taking anywhere from years to millennia. That means the high nitrate concentrations these communities now find in their water are the result of farming decisions made years and even decades ago—and “will persist well into the future,” even if farmers ramp down fertilization rates.
The reality is that the practices are unlikely to change anytime soon. The regions in question are two crucial nodes in California’s industrial-agriculture economy: the Tulare Basin in the southern Central Valley, a massive producer of milk, cattle, oranges, almonds, and pistachios, and the coastal Salinas Valley, which churns out about a half of the leaf lettuce and broccoli grown in the United States, and about a third of the spinach. Together, the two regions produce more than $12 billion in ag commodities and account for 40 percent of the state’s irrigated farmland and half its confined animal operations, according to an earlier Davis report.