A quarter-million residents of California’s Tulare Lake Basin and Salinas Valley may be drinking water contaminated with nitrate from fertilizer and animal manure, according to a study released Tuesday by a researchers at the University of California, Davis. As a result, these people who live and work in one of the country’s most productive agricultural regions are at greater risk of developing cancer, birth defects or other diseases from their drinking water.


The UC Davis study, which was featured in an article published Tuesday on msnbc.com and produced by the Food & Environment Reporting Network, is said to be the most comprehensive assessment of nitrate contamination in California’s agricultural areas. It found agricultural activity responsible for 96 percent of nitrate contamination in the five counties where it tested.

The researchers concluded that nearly 10 percent of the 2.6 million residents in the test area could be drinking the contaminated water. That number could be closer to 80 percent by 2050 if no improvements are made in the region, which accounts for 40 percent of California’s irrigated cropland. 

Nitrates from ammonium nitrate fertilizers seep into groundwater and wash into runoff water after being applied to crops. This excess of nutrients can cause eutrophication in lakes and seas by fostering rapid algae growth that causes heightened bacteria activity and oxygen depletion, leading to algal blooms and “dead zones” in which fish and other aquatic life cannot survive.

Infants are especially susceptible to nitrate overexposure, which can result in methemoglobinemia, or “blue baby syndrome,” where children face a decreased oxygen carrying capacity in their hemoglobin and risk death. Adults can experience the condition as well, and nitrate toxicosis has been linked to thyroid cancer, skin rashes and hair loss, the msnbc article reports.

Around the U.S., agricultural communities face similar threats from nitrates in drinking water. In Des Moines, Iowa, which sources its drinking water from the Des Moines river, the public utilities issues “blue baby” alerts to warn parents not to give their infants tap water when the runoff levels — and therefore fertilizer concentrations — are at their peak.