The paper in question, published in the Journal American Water Works Association, supports the safety of a common but frequently criticized way of incrementally removing lead pipes. The expression of concern came after years of back-and-forth letters to the editor between other scientists and the authors.
Lead water pipes have been causing lead poisoning for generations; some people have even theorized that the ancient Romans’ use of the metal facilitated the empire’s downfall. The dangers of childhood exposure to lead — delayed development, irreversible damage to the brain and nervous system and behavioral problems — have been documented in the U.S. since the 1940s, but the Environmental Protection Agency didn’t start regulating lead levels in drinking water until 1991, when the “lead and copper rule” went into effect. That set the standard for utility companies’ lead testing: if 10 percent or more of samples from homes had lead levels above 15 parts per billion, the companies were required to replace 7% of their lead pipes a year until they met the requirements.
Many public water systems have lead pipes leading from the main line into homes. Because homeowners are generally considered responsible for the part of the pipe on their property, utility companies often replace lead pipes with copper up to the property line.
This “partial lead service line replacement” is, according to many scientists, a cause for concern. Placing lead and copper next to each other has the potential to create galvanic corrosion, where lead corrodes more quickly in the presence of copper and water. That corrosion, which is the subject of the paper with the expression of concern, might increase lead levels in the water as it flows into the house.
A WATERSHED MOMENT
As a result of the “D.C. water crisis,” when a change in water treatment chemicals lead to dangerously high levels of lead being released into the water, almost 15,000 homes in the D.C. area had partial pipe replacements between 2004 and 2008. In 2010, the U.S. Centers for Disease Control and Prevention issued a report stating that partial replacements weren’t better than doing nothing at all, and in fact might be making blood levels in children worse. From the Washington Post:
The CDC said it “found that children living in housing where a lead service line was partially replaced after 2003 were more likely to have [elevated blood lead levels] than children living in housing without a lead service line.” It went on to say that “partial lead service line replacement was not effective in decreasing risk for [higher blood lead levels],” with the risk similar to that for people who never had their lead lines replaced.
But not all research has suggested partial-pipe replacements are dangerous. The expression of concern was issued on a 2012 paper called “Effect of Changing Water Quality on Galvanic Coupling,” which found, in part, that galvanic corrosion is “limited to a distinctly localized region” when the pipes are connected directly to each other, and “accelerated metal release with this type of galvanic coupling may be minimal.”
A number of other papers in the literature disagree with that conclusion. A few months after publication, Virginia Tech scientist Marc Edwards, who was a leading force in the investigation of D.C.’s water supply, and Ohio State corrosion scientist Gerald Frankel, sent Journal AWWA strongly worded criticisms of the article. Edwards’ seven page letter (paywalled) criticizes figures, states that the conclusions are not supported by the evidence and includes excerpts from the researchers’ emails (obtained from Journal AWWA editors) that suggest they wrote the paper before ever getting the data.
THE WATER WARS
The authors of the paper — funded by environmental and energy consulting firm the Cadmus Group and utility and industry group the Water Research Foundation — responded to the criticism (PDF). Then in 2014, the journal published an expression of concern that covers both the paper and some of the letters about it:
Individuals accessing this article and related documents (all of which are listed below) are urged to use caution regarding its results. Questions raised subsequent to publication were not fully answered by the authors. Journal encourages readers to be attentive to future research that may provide more clarity on this topic.
- Boyd, G.R.; Reiber, S.H.; McFadden, M.S.; & Korshin, G., 2012. Expanded Summary: Effect of Changing Water Quality on Galvanic Coupling. Journal AWWA, 104:3:45. http://dx.doi.org/10.5942/jawwa.2012.104.0038.
- Boyd, G.R.; Reiber, S.H.; McFadden, M.S.; & Korshin, G., 2012. Full Text: Effect of Changing Water Quality on Galvanic Coupling. Journal AWWA, 104:3:E5. http://dx.doi.org/10.5942/jawwa.2012.104.0038.
- Letters to the Editor, 2012. Galvanic Corrosion Article Draws Comment. Journal AWWA, 104:12:8.
- Edwards, M., 2012. Discussion: Effect of Changing Water Quality on Galvanic Coupling. Journal AWWA,104:12:65. http://dx.doi.org/10.5942/jawwa.2012.104.0151.
- Letters to the Editor, 2014. Concerns Continue Regarding Galvanic Coupling Article. Journal AWWA, 106:1:18.
The EoC was issued last year, but we have taken some time to sift through some of the evidence and background. It’s unclear whether the “authors” the note refers to includes just the study authors or also the authors of the letters, including Edwards. When we contacted Journal AWWA about the expression of concern, they told us to contact Edwards for more information. He responded:
My own impression is that the “expression of concern” means that the authors of the paper could not answer some of my simple questions, and that if you want to read more about it then look at all of the following articles. But I agree it is ambiguous wording…The paper is an outlier in suggesting that galvanic corrosion is never a significant concern, as both prior and subsequent research have confirmed that any physical connection between lead and copper can sometimes cause much higher lead in water.
PARTIAL REPLACEMENTS IN HOT WATER?
We spoke with Michael Schock, an EPA water specialist, about where this paper stands in the literature, and what’s going on with partial pipe replacements. He also told us that the paper is an outlier, with the majority of the literature supporting the idea that galvanic corrosion is possible when lead and copper are in contact. An effort to update the lead and copper rule is ongoing, and the National Drinking Water Advisory Council – part of the EPA – is leaning towards recommending utilities move away from partial pipe replacements, according to Schock.
“There’s too much evidence they can be bad, and therefore that shouldn’t be permitted,” he told us. But the policy isn’t changing any time soon. “We’re looking at one to two years before all the public comments are received and a revision issued. Then four to five years before it goes into effect fully,” he said.
Authors from the EoC’d paper also wrote a 2006 report on galvanic coupling prepared by the Cadmus Group for the EPA. It came to the same conclusion about galvanic corrosion — that it is localized and not a major concern. The data – some of which was used in the EoC’d paper – were presented to the EPA’s scientific advisory board when they were discussing partial pipe replacements.
Edwards filed a Freedom of Information Act request looking for the original data found in the 2006 report to the EPA, and when the Cadmus Group failed to provide it, Edwards asked the EPA’s Office of Inspector General to look into what happened. The EPA responded to Edwards’ request:
Our review is completed and we have determined that the allegations you raised do not rise to the level of criminal charges.
Boyd et al had an erratum issued for another paper published in Journal AWWA in 2009 on the chemical that caused the D.C. water crisis, telling readers to “disregard” a reference.
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