It's not No. 1 on the pollution enemy list, but those concerned about ground water say nitrate contamination is a growing threat in the Valley and throughout the nation.

Speakers from private industry, government and agriculture detailed the problem and possible solutions to nitrate contamination during a two-day symposium that ended Wednesday in Fresno.

The nitrate threat to ground water comes from various sources -- including nitrogen-based fertilizers, waste from dairy and other livestock operations and septic tank systems, both residential and industrial -- said William Pipes, president of the San Joaquin Valley Branch of the Groundwater Resources Association, which sponsored the symposium.

Experts say elevated nitrate levels in drinking water are a known health concern and ingestion can cause methemoglobinemia (blue baby syndrome) in infants and may form harmful carcinogenic nitrosamine compounds in humans.

"Nitrate remains one of the state's most widely recognized ground- water contaminants, and the problem may be growing," Pipes said.

Nitrate contamination is found most often in rural areas, and although the Valley is served by a giant aquifer from which it receives most of its drinking water, contamination most often is within "zones" beneath areas where concentrated uses are heaviest.

The good news, Pipes said, is that the problem can be solved. "Ground-water contaminants are here, and we can't wish them away," Pipes told participants at the conclusion of the symposium, "but we can manage them."

During a panel discussion, city of Fresno utilities director Martin McIntyre said the nitrates problem is not strictly confined to rural areas with dairy and other farm operations.

Fresno, with 250 water wells, has a significant problem dealing with chemicals and other contaminants, forming "an interesting contrast" with nitrate concentrations, McIntyre said.

Although no wells exceed the limits for nitrates, McIntyre said there is a problem created by old dairy sites and septic tanks.

There are 3,200 septic tanks still in the metropolitan area despite a city-county mandatory sewer ordinance, McIntyre said, and it can cost as much as $30,000 for homeowners to connect to sewers.

Nevertheless, he said, the city is working toward solutions. "I don't believe we have a problem that has overwhelmed us," he said.

State and federal agencies, as well as private industry, have ordered changes to mitigate the problem of nitrates, Pipes said.

Dairies, feedlots and cattle operations are heavily regulated and cannot be built without a plan to manage waste, said Pipes, the principal geologist at Geomatrix Consultants Inc. of Fresno.

Speakers at the symposium, held at the Radisson Hotel with more than 200 participants, discussed a number of ways that nitrates can be removed from water supplies.

Some of the treatment is as simple as introducing micro-organisms that use nitrates as a food source into soils. However, Pipes said, despite the advances and concerns by government, some scientists are warning that the worst is yet to come, since it takes years for nitrate on the surface to works its way into underground water.

"Our policy is we are not waiting for 'bodies in the streets,' " he said.

The reporter can be reached at jbier@fresnobee.com or 441-6484.


Related Links:

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> Symposium Resource Binders Available for Purchase
> Symposium Program Agenda