State: local water lead-freeBy Justin Nyberg
Lead levels in local drinking water have apparently not been effected by use of a new disinfectant, despite suspicions that the chemical may have been behind a recent lead scare in a major East Coast water system, according to state tests obtained by The Examiner.
State health officials asked local water agencies to conduct an extra round of testing this summer to see whether chloramine, a chlorine-based disinfectant, was causing pipes to leach lead into the system.
Of the patchwork of 15 water districts on the northern Peninsula, only the Guadalupe Valley Municipal Improvement District, serving an industrial part of Brisbane, failed to meet federal health standards of 15 parts per billion after chloramine was added to the system last February.
Two of the 12 properties tested failed the health standards. One building, at 155 Park Lane, showed lead levels at 30 parts per billion, twice the federal limit. Another showed 19 parts per billion. During the last testing in 2001, the highest lead reading was 5.9 parts per billion.
"I'd be really hesitant to make any assumptions ... until we've confirmed what the results are," said Randy Breault, an engineer for the city of Brisbane.
In Washington, D.C., the switch to the chemical was associated with the appearance of dangerously high lead levels in thousands of households in 2000. Scientists and water quality officials have not concluded whether this was directly caused by the addition of chloramine or by coincidental environmental factors, such as a change in the pH balance of the water.
Lead pipes are common in homes built more than 50 years ago. San Francisco and some other Peninsula cities have removed most of them. However, lead pipes, fittings and soldering still exist in some older homes.
Of the 41 older homes tested in San Bruno, 18 had lead service lines, and one showed unhealthy lead levels. City officials are looking at whether the owner recently used lead soldering on the pipes, according to Phillip Smith-Hanes, San Bruno's interim deputy public works director.
One problem with the tests, however, is that they were conducted only on a handful of homes. City officials often do not know which homes have lead pipes, leading some to question the thoroughness of the results.
Millbrae tested about 60 older homes and businesses, assuming some, at least, had lead pipes.
"We don't know exactly where those are. We suspect they are downtown," said Ron Popp, Millbrae's interim public works director. "We're pretty certain that we hit a couple of those, and they didn't test any different than they did before."
Also, lead level tests provide only a snapshot of a city's water quality. Individual homes may have widely varying results, based on whether lead soldering or pipe fixtures are used in the plumbing.
"It's not feasible to test every tap in the service area," said Manoucher Boozarpour, engineering manager of the Water Quality Bureau of the San Francisco Public Utilities Commission.
Residents can request a specific property be tested for a small fee.
Copyright ©2004 Peninsula Examiner. Published 12/03/2004.