A state investigation of leaking underground tanks has turned up significant ground-water pollution at five sites in Glendale and the San Fernando Valley area, raising concern about possible further contamination of public water wells that supply Glendale and Los Angeles.
"Alarmingly high" concentrations of methylene chloride and trichloroethylene (TCE), both suspected cancer-causing solvents, have been found in ground water at Mepco / Centralab Inc., 4561 Colorado Blvd., which is between the Los Angeles River and the Glendale city line, according to documents on file with the California Regional Water Quality Control Board in Los Angeles.
Close to Contaminated Wells
The site is about a mile from several Los Angeles and Glendale water wells that have been contaminated by trace amounts of chemical pollution, although there is no evidence that any of it came from Centralab.
"We're just monitoring the situation," said Glendale's water services director Michael Hopkins. He said officials are "not overly concerned at this point."
None of the sites appears to pose an immediate threat to drinking-water quality. But, unless cleaned up, the pollution "would show up eventually at some well sites in the future," said Laurent McReynolds, an assistant chief engineer with the Los Angeles Department of Water and Power.
McReynolds said he suspects that the sites "are just the tip of the iceberg" and that "there are literally dozens to hundreds of situations like this" in the area that have not yet been fully investigated.
The other four sites:
Technicolor Inc., a film laboratory at 4050 Lankershim Blvd., where ground-water tests have revealed high levels of TCE and perchloroethylene (PCE).
Universal Studios, within a block of Technicolor, where ground-water tests have revealed high concentrations of other industrial solvents and of leaked fuel.
Technicolor and Universal are adjacent to the channel of the Los Angeles River, a largely underground stream that replenishes municipal water-well fields in downstream areas of North Hollywood, Glendale and Los Angeles.
Rockwell International's Rocketdyne plant at Canoga Avenue and Vanowen Street in Canoga Park, where ground-water pollution was confirmed last year and where recent tests have shown off-site seepage toward the river channel less than a quarter of a mile away.
Riker Laboratories Inc., a pharmaceutical plant in Northridge, where high levels of chloroform, methylene chloride and other chemicals have been found in ground water, some of which has migrated off the site, according to a report last month to the regional water-quality board.
The Los Angeles DWP draws about 15% of the city's water from wells clustered near Vanowen Street and Tujunga Avenue in North Hollywood, and along the Los Angeles River from North Hollywood past Griffith Park. Water from these wells is served to areas of the city east and south of the Santa Monica Mountains. Glendale draws about 20% of its water supply from ground water.
The Los Angeles well fields and neighboring ones operated by Burbank and Glendale have been named to the state and federal Superfund lists of contaminated sites needing priority attention because of pollution by TCE and PCE. These solvents, widely used in dry cleaning and to degrease metal, are suspected of raising the risk of cancer in persons exposed over long periods.
Since the problem was discovered about six years ago, officials generally have kept tap-water contamination within health guidelines by shutting down the most polluted wells and by mixing water from mildly contaminated wells with clean aqueduct supplies.
For example, four of the nine wells in Glendale's Grandview field, about a mile north of the Centralab plant, have been closed in recent years because of contamination by TCE. Because of the gradient in the area, water seeping beneath the plant would normally move south, making it unlikely that the Grandview wells would be affected. However, water officials said area ground-water flow can reverse if upstream wells of Glendale, Los Angeles and Burbank are pumped more than downstream ones.
Water officials, pointing out that ground water moves through the soil at no more than a few hundred feet per year, attribute most existing well pollution to events of 10 years ago or earlier. They say that, along with tank leaks, seepage from septic disposal systems, accidental spills, deliberate illegal dumping and leaky landfills probably have contributed.
To head off more pollution, the regional water-quality board two years ago directed some area businesses with aging underground tanks to check them for leaks. Other sites came to the board's attention through local enforcement of integrity standards for new tanks. At many of these sites, buried tanks have been removed, tainted soil has been cleaned and testing is under way to see if contaminants have reached ground water.
Most Significant Pollution