Temporary Aqueduct Problem Called No Big Hazard : State Prompts a Warning on Taint in L.A.’s Water

Higher-than-advised concentrations of a suspected cancer-causing solvent are being pumped into some of the city water supply because of a temporary breakdown in the Owens Valley Aqueduct, state and city officials cautioned Friday.

The warning was issued at the urging of state Department of Health Services officials, who complained that the Department of Water and Power had objected to making an announcement out of fear it might cause undue alarm.

The disclosures come on top of DWP test findings that, during six months of the last three years, water supplied to some Los Angeles homes and businesses from wells in the San Fernando Valley has exceeded state advisory limits for trichloroethylene, or TCE.

Aqueduct Break

State and local officials said the immediate TCE problem developed when a break in the aqueduct last weekend forced the DWP to begin pumping more water from Valley wells to make up for shortages caused by the interruption in service.

About 75 DWP wells clustered between the North Hollywood area and Griffith Park provide roughly 15% of the city’s water. The well water rarely is piped to Valley homes and businesses but makes up at least part of the supply for about 400,000 people in East, Central and West Los Angeles, according to the DWP.

The state was informed Thursday that TCE levels now are 12 parts per billion, well above the state advisory standard of five ppb.

State officials, however, do not consider this level to be dangerous to public health because the problem is temporary and will be solved when the aqueduct is back in service, probably by Oct. 21.

Scientific Estimates

In efforts to minimize the perception of danger, officials cited scientific estimates that, if a person drank two quarts of water containing five ppb of TCE for 70 years, he would have only a one-in-a-million greater chance of contracting cancer.

Still, state officials insisted that Los Angeles water customers be notified.

“We don’t consider it a public health threat, but we do believe the public has a right to know,” said Pete Rogers, chief of the sanitary engineering branch of the state health department.

Assemblyman Gray Davis (D-Los Angeles), a member of the Assembly Health Committee, said knowledge of the increased hazard, however small, should be available to the public so people could, if they wish, take precautionary measures such as buying bottled water until TCE levels in the water go down.

Awareness of Risk

Davis said: “I don’t intend to use bottled water myself. I think the danger is very, very slight. But I would feel cheated if I was unaware of the increased risk.”

After the concern expressed by state officials, city officials agreed to help release the information.

But Ali Webb, press secretary to Los Angeles Mayor Tom Bradley, released a letter from DWP General Manager Paul Lane to state health department Director Dr. Kenneth Kizer asserting:

“While we agree with you that the public certainly should be informed when there is a health risk associated with their water supply, we are puzzled why you are requesting such public notice, since you agree with us that there presently is no health risk to any of the water customers in the city of Los Angeles.”

The letter says the advisory five-ppb level was an “annual average” and that the TCE levels were not approaching the 20-ppb level that had been set as a “daily” limit.

Standard Exceeded

DWP test data reviewed earlier by The Times shows that the average amount of TCE in water from the Valley wells exceeded the advisory standard of five ppb during four months in 1982 and two months in 1984.

The data appears to conflict with public statements by the utility that its practice of closing polluted wells or blending their water has assured that water reaching customers is under the TCE limit.

But a high-ranking DWP official said there is no inconsistency between the test results and statements by the utility, since the yearly average of TCE in the water has stayed below the five-ppb advisory level.

“I don’t think the public has been misled on it,” said Laurent McReynolds, assistant chief engineer of the water system. “They’ve not been put at any greater risk.”

During the last five years, many wells have been found to contain TCE and a second common industrial cleanser, perchloroethylene, or PCE, at levels above state advisory limits, also known as “action levels.” In response, the DWP has stopped pumping from some of the wells and has blended water from others with cleaner aqueduct water to dilute the contaminants.

Because of these efforts, a 1983 DWP report says, “only water in compliance with the recommended quality guidelines was delivered to the customer for consumption.”

But DWP data shows that TCE in the well water averaged 6.6 parts ppb in June, 1984; 8.3 ppb in May, 1984; 9.1 ppb in November, 1982; 7.1 ppb in October, 1982, and 8 ppb in both July and August of 1982. The DWP tests showed that monthly average concentrations of PCE have never topped the action level for that chemical since monitoring began more than three years ago.

Not Examined at Tap

The measurements were taken from a water supply conduit--not at the tap--making it likely that some of the TCE, which is highly volatile, evaporated before reaching customers, DWP officials say.

McReynolds said that, in effect, the action level, which is not a legal standard, never was violated because it is intended to limit chronic rather than temporary exposure to TCE. Test results show that average TCE levels have topped 4 ppb but have never averaged five ppb during any one-year period.

TCE is not a proven human carcinogen but has caused cancer in laboratory animals exposed to large doses. The state advisory standard merely represents a scientific guess as to the amount of TCE in water that could raise, by a minimal amount, each person’s already considerable risk of eventually getting cancer.

Experts say that about 30% of Americans living today eventually will contract some form of cancer, and that the percentage will be greater for people who smoke.

Informal Policy

The state Department of Health Services, which set the guideline, has had an informal policy of requiring utilities to notify customers when water exceeds action levels.

However, that policy has not been followed by the DWP, which convinced officials in the state agency’s Los Angeles office that compliance with the action level should be based on a 12-month average of TCE in the water.

Gary Yamamoto, a senior engineer with the state agency, said there is no set policy on what constitutes compliance with action levels. He said the agency felt comfortable with the DWP’s 12-month averaging method because the utility “does a lot more monitoring of their system than others do.”

Yamamoto said the DWP provides twice-daily TCE measurements, whereas some other utilities test for the compound once a month. He said it is possible for such utilities to fudge the results by sampling only on the days when most of the polluted wells are turned off.

McReynolds said there was no cause to notify the public during months the TCE limit was topped because the situation was temporary.

‘Disservice to Public’

“Under those conditions there was no increased risk to the public,” he said. “I think it would be a disservice to the public to notify them of something that is not a risk to them and have them believe it is a risk,” McReynolds said.

Dr. Alex Kelter, who heads the state health department’s office of environmental health hazard assessment, said the measurement of contaminants at parts-per-billion levels is imprecise to begin with. Lab error, he said, can account for readings that slightly exceed or fall short of the action level.

The action levels should not be “viewed as black-and-white cutoffs between safe and unsafe,” Kelter said. Rather, he said, they should raise “the red flag or maybe the yellow flag and say, ‘What are we going to do about this in the long run?’ ”

According to DWP tests, contamination generally has been spreading to more Valley wells, apparently because decreased pumping of the most polluted wells has allowed tainted ground water to move farther downgrade. DWP officials say they believe the contaminants leaked or were dumped into the ground years ago by industries.

The DWP wells and neighboring well fields in Burbank and Glendale have been designated Superfund sites, making them eligible for money for studies and cleanup from the federal toxic-waste cleanup program. The DWP recently asked the federal Environmental Protection Agency for $2 million from the Superfund to build collector lines and an aeration tower in North Hollywood to contain the spread of contaminants and start cleanup of the water. The plan calls for pumping water up the tower and blasting it with air to eliminate chemicals through evaporation.