WASHINGTON (AP) -- Unhealthy levels of pesticides and nitrates are believed to be contaminating wells that provide drinking water for hundreds of communities, the Environmental Protection Agency said yesterday.
EPA officials emphasized that a nationwide sampling of wells indicated that fewer than 1 percent are contaminated to levels that are of concern.
But those wells provide drinking water for millions of people, the officials said.
While the "vast majority" of the country's drinking water wells don't pose a risk to public health, the findings provide an "early warning sign that this needs to be taken seriously," said Henry Habicht, the EPA's deputy administrator.
Ron Phillips, a spokesman for the Fertilizer Institute, said the survey confirms that "at least 96 percent of our ground water is perfectly safe."
But he disputed that the levels of nitrates found in some of the well water should be of concern. "Nitrate is not a dangerous chemical," he said. "It's a naturally occurring substance with almost no health effects."
The EPA survey covered 1,347 wells in 50 states, including private wells and wells that feed community water systems.
From the results of the survey, the agency estimated that about 10.4 percent of community wells and 4.2 percent of private wells contain some pesticides.
The survey also indicated that more than half the nation's wells have water contaminated with nitrates from fertilizer, sewage sludge or septic tanks.
About 2.4 percent of the community wells are believed to have nitrate levels that pose a health concern.
Many of the pesticides found in the drinking water are suspected of causing cancer or damage to vital organs if consumed at significant levels over a long period of time. High levels of exposure to nitrates can cause "blue baby" syndrome in very young infants, as well as other illnesses.
In most cases, the water contamination is believed to be below levels that pose a health concern, the EPA said. But it added that the findings indicated that as many as 750 community water systems may have wells that have pesticide or nitrate contamination exceeding federal health standards. The EPA estimated that nearly 80,000 private wells in rural areas have similar contamination.
"The EPA survey reinforces existing strong evidence that nitrates are contaminating ground water," said Justin Ward of the Natural Resources Defense Council, a Washington-based environmental group.
But, the NRDC and other environmentalists also criticized the EPA for focusing on the entire country rather than only on areas where pesticides and nitrogen fertilizers are heavily used. They maintain that national figures understate the seriousness of the problem in some regions of the country.
The two most frequently detected pesticides found in well water were dacthal, a broadleaf weed killer used primarily on lawns, and atrazine, a weed killer widely used in agriculture, especially on corn and sorghum, the agency said.