With the recent emergence of lead contamination problems in Washington, D.C., and other U.S. cities, the San Francisco Public Utilities Commission (SFPUC) and other Bay Area water agencies have agreed to conduct an unscheduled round of lead testing of their water this summer.
The sampling request was made by the California Department of Health to determine whether SFPUC's recent switch to chloramines to disinfect its supply could be disturbing corrosion control treatment intended to limit lead corrosion from household plumbing, which is a suspected cause of problems being experienced by the D.C. Water And Sewer Authority (WASA).
While U.S. EPA has stated that use of chloramines at low levels in drinking water will not adversely affect public health, concerns have been raised that such a major treatment change can disturb corrosion control treatment put in place years ago by many water systems to comply with the Lead and Copper Rule.
Chloramine has been added to SFPUC's water since February as an alternative to chlorine. However, lead pipes in San Francisco-area homes are much rarer than in homes served by WASA, primarily because SFPUC conducted an aggressive campaign to remove them in recent years. They do exist, however, in older suburban homes in some communities.
Andrew DeGraca, SFPUC's Water Quality Bureau manager, said the utility is now holding planning sessions about the upcoming lead-testing program.
"Some of our wholesale customers will be doing it, some not," said DeGraca. "It's a massive undertaking and we're now in discussions, but nothing has been agreed to yet."
DeGraca said a small group of citizens in the nearby Millbrae (Calif.) area have expressed concerns about the utility's switch to chloramine, saying they are worried about the chemical's possible negative health effects. "We have urged them to go to their doctors, but the doctors are not saying their problems are due to the water," he said, noting there is no definitive data on the effects of chloramine in water on human health.
SFPUC is now referring all questions about chloramine in water to the San Francisco Department of Public Health (SFDPH). At the same time, the utility is also doing its own research on the matter. "We're going to be responsive and look into the issues raised," DeGraca said.
SFPUC, DeGraca said, is now in the process of preparing a question-and-answer fact sheet on chloramine and its relationship to disinfection by-products (DBPs) that will update the utility's currently published information on the subject, including information on nitrosodimethylamine (NDMA), one of the by-products of concern. The updated material will then be posted on SFPUC's website for easy public access.
June Weintraub, an SFDPH epidemiologist, said the department will "consistently monitor for NDMA and other disinfection by-products" now that SFPUC has made the switch to chloramine. She said high levels of DBPs are "not anticipated, given the high-quality water source and treatment practices" of the utility.
Chloramine, a phosphate inhibitor, has been used in water supplies in California since 1985 and in the U.S. since 1930, DeGraca said, adding that if investigations show that chloramine is indeed a problem in water, it would be a "major paradigm shift" from what has been learned about it previously. "We were one of the last in the state to convert to chloramine," he noted.
He said the utility has already seen the benefits of chloramine conversion. "Our peak levels of DBPs are down and we have record lows of total coliform," he said.
Meanwhile, according to a story in the Honolulu Star Bulletin, a citizens' advocacy group is asking the Maui Department of Water Supply (MDWS) to halt the use of chloramine in drinking water because they say it can increase the amount of lead pipe leaching.
The Maui Coalition for Safe Water says some studies show that chloramine, a phosphate inhibitor, increases the amount of lead leaching into water when combined with phosphoric acid.
According to the story, a state Health Department spokeswoman said a small number of preliminary tests revealed that lead content in some samples of local water were at 41 micrograms/L, well above U.S. EPA's 15-micrograms/L action level, and that more testing will be done later this month.
The MDWS held a public meeting earlier this week to address the issue.
Source: AWWA
