Do in-line brass devices leach lead?
In August, the American Water Works Association (AWWA) published a study in their journal examining the risk of lead leaching from inline brass plumbing products into drinking water. In the U.S., 44 states currently require these devices to comply with the requirements of NSF/ANSI Standard 61: Drinking Water System Components—Health Effects, (NSF61). The article cited experiments that examined the practical rigor of the Standard and the study concluded that it was not highly protective of public health.
Since its publication, the report has appeared in a variety of incarnations online and in print. We at NSF International disagree with its conclusions and would like to take this opportunity to clarify some of the key issues addressed by the original research.
The article, written by Abhijeet Dudi and Marc Edwards of the Virginia Polytechnic Institute and Michael Schock and Nestor Murray of the U.S. EPA, claims that, “small devices made of pure lead—which pose an obvious public hazard—can easily pass the leaching protocol… [and] brass devices passing the test can contribute to lead levels at the tap in residences, schools and other buildings.” However, the tests conducted on the small lead device omitted certain requirements in NSF 61. The result is a host of conclusions about Standard 61 with which NSF disagrees and that may be misleading to the general public.
A key fact not stated in the article is that the authors sent much of the information in this paper to NSF in November of 2004. The Joint Committee that oversees Standard 61 reviewed this information and the Standard was revised in March 2005 to require all exposure water to be prepared fresh daily and stored in closed containers, although some of the ANSI-accredited certifiers on the Committee report that this was already common practice. The Committee also developed a task group to review every aspect of the testing and evaluation of lead leaching and one of the co-authors of the original research is a member of the task group.
The authors claim that a solid lead device meets Standard 61 requirements when tested with pH 5 test water. This is based on a misapplication of the test protocol and leads me to wonder why the authors did not test, or report test results, for the solid lead device with the required, unaerated pH 10 test water? The pH 10 exposure water is an essential and inseparable part of the test protocol as it is highly aggressive for lead. If that pH 10 exposure water had been utilized instead of a pH 5, the solid lead device clearly would have failed to pass the Standard. This fact is not stated in the text of the paper and gives the impression that pH 5 water was intended to be aggressive for lead as part of the protocol when in reality, the pH 5 water is used because it is aggressive for copper and nickel.
A second, but equally important concern with the paper is the suggestion that the NSF standards development process is not open to public scrutiny. As noted above, our Joint Committee took immediate action based upon the scrutiny provided by the authors last year. Their input came directly out of contributions made during a public meeting of the Joint Committee.
Based on our experience at NSF, numerous devices made from brass alloys with less than eight percent lead have failed to meet the rigorous requirements of Standard 61 due to the aggressiveness of pH 10 water. We have even seen lead failures when brass products that are so-called lead-free were tested. This is because foundries that run both leaded and non-leaded brass are at risk of cross-contamination that can be detected by the NSF protocol, a further demonstration of the sensitivity of the complete test.
According to the Safe Drinking Water Act, the lead content in a plumbing product must be less than eight percent. Moreover, a recent survey of products submitted to NSF for evaluation under Standard 61 shows that 89 percent of all metal parts in valves and water meters contain less than 3.7 percent lead and two-thirds contain less than 0.5 percent lead. We attribute this consistently decreasing amount of lead in new plumbing products over the past decade to manufacturers’ desires to receive Standard 61 certification and a sign of NSF’s commitment to protecting the public health.
For more information on the NSF/ANSI Standard 61 certification process, contact NSF International at 1-800-NSF-MARK, or see our website at www.nsf. org.
General Manager of the Water Distribution Systems at NSF International
(734) 827-6855; [email protected]