Drink Up, Rio Rancho
Silica in groundwater is not considered a contaminant by the EPA
The Alibi reported former New Mexico Assistant Attorney General Jon Adams funded an investigation of high levels of silica found in two private wells in Rio Rancho [“ Well Wishes,” Jan 10-16]. These wells contained five to seven times the average level of silica found in drinking water. Seven months later, Adams says the investigation is on hold. “We’re concerned about the high level of silica in the water, because something that high could still be a problem," he says. "I’m concerned about it, but there’s no additional investigation right now." Further examination of the issue was dropped because of the EPA's dismissal of silica as a potential contaminant.
I don't want to call it a non-issue, but there haven't been any health effects associated with silicates in drinking water.
Mike Huber, manager of the Drinking Water Bureau of the New Mexico Environment Department
While there are about 100 components regulated under the Safe Drinking Water Act, silicates are not among them. Silica is the natural compound found in sand and is not considered to be a contaminant or a health threat.
Adams wrote to the EPA in December 2007 about the health threats silica could pose to Rio Rancho residents. He worried the silica in the drinking water could be related to high levels of silica in the air. When silica is airborne, it can cause silicosis, a serious lung disease. Mike Huber, manager of the Drinking Water Bureau of the New Mexico Environment Department, says silicosis is mostly an issue for those inhaling silica in their daily work environment. Silicosis, he says, does not result from drinking water. "I don't want to call it a non-issue," he says, "but there haven't been any health effects associated with silicates in drinking water."
The EPA is not concerned about the high levels of silica found in the wells partly because silicon dioxide, or sand, is naturally prominent in the desert. In response to Adams’ letter, the EPA stated the finding of silica in water isn’t directly correlated to the silica levels in the air. There is no reason, the EPA continued, to assume high silica content in the groundwater is a result of silica deposits in the atmosphere.
While Adams remains concerned, David Bary, spokesperson for the EPA, says the agency did not conduct an investigation because silica is not a substance that is monitored. “If it was regulated and had a contaminant level that was exceeded, then [the Rio Rancho wells] would be a violation. But the agency doesn’t have the authority under the Safe Drinking Water Act to regulate silica in drinking water,” Bary says.
If anything, silica can affect the hardness of the water, Huber says, but this is merely an aesthetic effect and not a health issue. Despite Adams' anxiety earlier this year and the fact that silica is not a substance regulated by the EPA, Adams says he has not had a chance to follow up on the issue: “It’s on hold. I’m not taking any additional steps right now."