New Rules for Nitrates

Janice Kaspersen,  Stormwater Editor Comments
March 20, 2012

Nitrate pollution is getting a lot of attention in California. Even as other states—notably Florida—enact TMDLs for nutrients, California’s Central Coast Regional Water Quality Board recently adopted new rules for agriculture, requiring ag operations to reduce nitrate and pesticide pollution.

Just before the new rules were announced, the University of California–Davis released a study showing that in some areas of the state, 96% of the nitrate contamination in groundwater is a result of fertilizer and animal waste. Five counties were included in the study, comprising about 40% of the state’s irrigated agricultural land and half its dairy herds. The agricultural industry had previously argued that it’s impossible to identify the source of the nitrate because it can come from many different sources, such as septic systems, water treatment plants, and landscape fertilizers.

As this article reports, drinking water with high levels of nitrate—as may be the case especially for residents relying on private wells—has been associated with a number of disorders, including thyroid cancer, birth defects, and “blue baby syndrome,” which reduces the blood’s capacity to carry oxygen, as well as to less serious health problems. The UC Davis study reports that as many as 260,000 people in Salinas Valley and the Tulare Lake Basin might be drinking water with high nitrate levels. However, because the current groundwater contamination likely results from nitrates that entered the soil years ago, there may be a significant time lag between the reduction of nitrates applied today and the clearing up of the groundwater pollution.

The Environmental Working Group reports that Congress is considering future funding levels for land and water conservation programs, which would provide farmers with support for the requirements of California’s new rule, such as managing erosion, pesticides, and nutrients.