California Farms Get Testy Over Water Quality - Miller-McCune
California Central Coast row-crop farmers are now required to test their private wells for nitrate, a widespread groundwater contaminant linked to over-fertilization.
The world’s most pervasive groundwater pollution problem - nitrate in drinking water - is under scrutiny in the richest farming region of the United States.
This week, a report for the California Legislature revealed that 250,000 people living in Central California, including four of the top five agricultural counties in the U.S., are currently at risk for nitrate contamination in their drinking water. Many of them are among the poorest Californians.
Nitrate, in this instance, is a byproduct of nitrogen fertilizer. In drinking water, high concentrations of it can interfere with the oxygen-carrying capacity of infants younger than six months, and, if left untreated, may lead to death from “blue baby” syndrome. Some studies suggest that long-term consumption of nitrate in drinking water may increase the risk of Parkinson’s disease, Alzheimer’s disease, and cancer, including non-Hodgkin’s lymphoma.
Europe began tackling the problem in 1991 by designating “vulnerable zones” where the groundwater and streams were polluted with nitrate. Those zones now encompass 40 percent of the landmass in the continent. Today, 27 countries test for nitrate at 31,000 monitoring stations on or near farmland; and, with some overlap, at 27,000 monitoring stations in lakes, streams, and the ocean. Since 1991, reports show, nitrate use has dropped off sharply in Europe.
In the U.S., the United States Geological Survey estimates that as many as 7 percent of private wells and 3 percent of public wells may be contaminated with nitrate, with the highest concentrations found around irrigated farms.
In Central California, according to the state report, cropland is the source of more than 90 percent of the nitrate that winds up in underground basins. Contamination can take a long time: some of the nitrate in well water today comes from fertilizer that was applied a century ago. The report, prepared by the University of California, Davis, recommends charging farmers higher fees for fertilizer and using the money raised to help rural communities pay for expensive water treatment systems.