"First and foremost, this is about getting safe drinking water to people," said report co-author Thomas Harter of the UC Davis Department of Land, Air, and Water Resources. "In the intermediate and long-term, it's about fixing the source of the problem."

The report also calls for a statewide effort to integrate water-related data collection by various state and local agencies.

"The report defines the extent and costs of the problem, for the first time, and outlines how we can address it," said Harter. "We hope it provides the foundation for informed policy discussions."

Key findings include:

  • Drinking water supply actions, such as water treatment and finding alternative water supplies, are most cost-effective. However, well supplies will become less available as nitrate pollution continues to spread.
  • While many options exist to provide safe drinking water, there is no single or ideal solution for every community affected.
  • Agricultural fertilizers and animal manure applied to cropland are the two largest regional sources of nitrate leached to groundwater -- representing more than 90 percent of the total.
  • Reducing nitrate in the groundwater is possible, with methods such as improved fertilizer management and water treatment. Costs range from modest to quite expensive.
  • Directly removing nitrate from large groundwater basins is extremely costly and not technically feasible.

Part of the natural global nitrogen cycle, nitrogen is a key element that plants require for growth. Yet, in addition to contaminating groundwater, the surge in human-related nitrate over the past century has also created marine "dead zones," nitrogen oxide emissions that contribute to climate change and a host of other environmental problems.

The State Water Board will be conducting a public workshop on May 23 to consider public comment, as well as discuss the findings and options outlined in the UC Davis report. The board will review the public comment and issue recommendations to the state Legislature, as called for in the legislation.

The board has posted the documents on the Internet for public review and comment at http://www.waterboards.ca.gov/water_issues/programs/nitrate_project/index.shtml.

For the full UC Davis report, videos, maps, and more information, visit http://groundwaternitrate.ucdavis.edu.