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Pipes may leak lead

Posted: August 29, 2009 10:00 p.m.
Updated: August 30, 2009 4:55 a.m.
 

Santa Clarita Valley water agencies said they don't use PVC pipes, which recent studies have shown to leech lead into the water they carry, but the inexpensive plastic piping has become popular in the construction of new homes, officials said.

"We don't have PVC as part of our conveyance system," said Dan Masnada, general manager for the Castaic Lake Water Agency. A series of studies show PVC pipes could leech lead into the drinking water they carry, and though local water purveyors don't use the pipes, officials said they are commonly used in new homes.

University research has shown the pipes could break down through a complex process that would eventually cause lead to dissolve into drinking water. PVC is becoming more common in water systems around the company because the material is 30 percent cheaper than other pipes.

However, those concerned about the prospect of lead-infused water can take a simple precaution, experts said.

"Don't drink from the first draft," said David Kimbrough, a chemist for the Castaic Lake Water Agency. "Let the faucet run for 30 seconds."

The potential dangers of PVC, or polyvinyl chloride piping, has drawn the attention of advocacy groups and the federal Environmental Protection Agency, said Lou Moussante, chemist for the Clean Water Pipe Coalition.

The coalition crusades to get water companies and homebuilders to use other material besides PVC to convey water.

The lead risk associated with PVC comes from nitrification, Moussante said.

He described the complicated process in which parts of the pipes break down into lead:

It begins when water utility companies use chlorine to purify drinking water.

"It breaks down into ammonia, which supports the growth of bacteria," he said. "Those bacteria, in turn, lower the pH of the water" and make it acidic. The corrosive water breaks down the brass fixtures in the home into its core components - which often includes lead - and leeches the toxic metal into drinking water.

Lead levels in water piped through PVC can be 65 times higher than what comes through ductile pipes, Moussante added.

Moussante referenced research done at Virginia Tech University, on which Kimbrough conducted peer review.

According to Kimbrough, a clear connection to PVC nitrification and brass corrosion are not cut and dry.

"The corrosion of brass is complex," he said. Kimbrough acknowledged nitrification occurring in drinking water systems, but said the impact of lower pH water on brass has mixed results.

Brass is an alloy or mix of metals including copper, zinc and in some cases lead. When brass corrodes, the zinc is pulled out of the alloy and, on occasion, so is the lead, Kimbrough said.

While lead in water conjures the specter of physical and mental deficiencies in young children, Kimbrough said the solution to the problem is simple.

"Your greatest exposure to lead is from the first draft from when you first turn on the faucet," he said. "Don't drink from the first draft."

Lead takes time to dissolve into drinking water so running the faucet for 30 seconds will remedy any problem with lead contamination.

On the retail side, PVC is not used to connect water mainlines to homes through service connections, said Steve Cole, general manager for Newhall County Water District.

"We use ductile pipe for our conveyance system and copper in our service lines that run to our customers' homes," he said. The same is true of the water system throughout the Santa Clarita Valley, Kimbrough said.

PVC is flimsy and not nearly as reliable as ductile pipe, Moussante said.

New home construction often employs PVC pipe, but Kimbrough said again that if anyone is worried about the prospect of PVC pipes leeching lead into their drinking water, there's a simple solution.

"Just let the faucet run," he said.

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