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 Tuesday by researchers at the University of California, Davis.
Nearly 10 percent of the 2.6 million people living in the Tulare Lake Basin and Salinas Valley might be drinking nitrate-contaminated water, researchers found. And if nothing is done to stem the problem, the report warns, nearly 80 percent of residents could be at risk of health and financial problems by 2050.
High nitrate levels in drinking water have been linked to thyroid cancer, skin rashes, hair loss, birth defects and “blue baby syndrome,” a potentially fatal blood disorder in infants.
The report is the most comprehensive assessment so far of nitrate contamination in California’s agricultural areas.
The problem is much, much, much worse than we thought,” said Angela Schroeter, agricultural regulatory program manager for the Central Coast Regional Water Quality Control Board, a state water agency.
Nitrate-contaminated water is a well-documented fact in many of California’s farming communities. The agricultural industry, however, has maintained that it is not solely responsible because nitrates come from many sources. But, according to the UC Davis report, 96 percent of nitrate contamination comes from agriculture and only 4 percent can be traced to water treatment plants, septic systems, food processing, landscaping and other sources. While the report focused on California, nitrates in groundwater is a problem that plagues farming communities around the U.S.
A financial hit as well
In addition to health risks, tainted water will exact a growing financial toll, the report said. The researchers project that utilities and citizens in the two regions will pay $20 million to $36 million per year for water treatment and alternative supplies for the next 20 years or more.
According to the study, more than 1.3 million people in the two areas currently face increased costs as residents seek alternative sources of water and providers pass on the costs of treatment to ratepayers.
The five counties in the study area – among the top 10 agricultural producing counties in the United States – include about 40 percent of California’s irrigated cropland and more than half of its dairy herds, representing a $13.7 billion slice of the state’s economy.
The Central Coast Regional Water Quality Control Board has produced several reports of its own that show “large-scale degradation” of drinking water aquifers due to nitrates from fertilizer.
“If we don’t address this, we’re going to have a very serious issue in California,” Schroeter said.
Nitrates are odorless, tasteless compounds that form when nitrogen from ammonia and other sources mix with water. While nitrogen and nitrates occur naturally, the advent of synthetic fertilizer has coincided with a dramatic increase in nitrates in drinking water.
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.