Lead Levels in Drinking Water Spike When Copper and Lead Pipes Joined

http://www.sciencedaily.com/releases/2011/12/111215113523.htm

ScienceDaily (Dec. 15, 2011) — Lead pipes once used routinely in municipal water distribution systems are a well-recognized source of dangerous lead contamination, but new research from Washington University in St. Louis suggests that the partial replacement of these pipes can make the problem worse.

The research shows that joining old lead pipes with new copper lines using brass fittings spurs galvanic corrosion that can dramatically increase the amount of lead released into drinking water supplies.

"Work done in our laboratory shows galvanic corrosion in joined service lines is significant and lasts for a long time," says Dan Giammar, PhD, the Harold D. Jolley Career Development Associate Professor in the Department of Energy, Environmental & Chemical Engineering at Washington University in St. Louis.

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His experiment reveals that instead, it could be far worse. The joined lead-copper pipe in his lab releases five times more lead than did the original lead pipe.

The lead is released by galvanic corrosion, a process set up whenever two dissimilar metals are immersed in a conducting liquid.

The same thing happens if lasagna or another acidic dish is made in a stainless steel pan, covered with aluminum foil, and placed in a refrigerator. The two metals and the lasagna act as a galvanic cell, and some of the aluminum may migrate out of the foil and plate out on the surface of the lasagna.

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