PASADENA — When city officials first heard that the organic chemical trichloroethylene (TCE) was contaminating ground water in large sections of the San Gabriel Valley in 1979, they barely raised an eyebrow.
The problem had surfaced miles away in Azusa and there was nothing to suggest that the cancer-causing chemical would find its way into Pasadena's ground water.
"We weren't concerned at all, but we figured it would be good PR if we tested our own wells to show everybody how clean they were," said Willard O. Bangham, water system administrator.
But instead of good public relations, city officials got a shock when tests in 1980 showed that TCE was contaminating ground water in large sections of northwest Pasadena and Altadena.
Since then, the city has spent six years testing, analyzing and charting the slow spread of TCE through an underground depression in northwest Pasadena called the Monk Hill sub-area.
Other Cities Interested
This month the city will finally take its first step toward correcting the problem with a $145,000 pilot purification project that is being closely watched by other cities, including Los Angeles and Burbank, which face similar contamination problems.
The Pasadena pilot project is unusual in that it will use a relatively new process combining the powers of ultraviolet light and ozone to break down volatile organic chemicals, like TCE, into safe components.
The UV and ozone process has been successfully used to purify extremely contaminated water at aerospace, automobile and semiconductor plants around the country, said Thomas K. Underbrink, water system engineer.
But it has never been used to purify drinking water, and no one is sure if it is economical and reliable enough to treat large volumes of water over several decades, he said.
Underbrink said that if the pilot project is successful, it could clear the way for Pasadena, as well as other cities, to solve water pollution problems with a process that is relatively safe, simple and inexpensive.
Based in Arroyo Seco
The project will be based in a trailer in the Arroyo Seco, purifying less than 100 gallons of water a minute in a file cabinet-sized tank.
If all goes as planned, the city expects to have a full-scale purification plant operating in two years, Underbrink said. The total cost has been estimated between $3 million and $5 million, he said.
According to a city study completed in November, the TCE contamination in Pasadena probably was caused by the dumping of solvents at the Jet Propulsion Laboratory from the early 1940s to as recently as 1962.
Fred H. Felberg, institutional associate director for JPL, said the lab has accepted probable blame for the contamination and has agreed to pay for nearly half the pilot project.
In addition, the lab probably will help pay for future expenses, he said. "We haven't gotten down to the nitty-gritty, but in principle we are committed to participating in this."
Methods Changed in 1962
Felberg said that since 1962, the lab has strictly controlled the disposal of hazardous wastes, which are now placed in temporary holding tanks and then hauled away to approved disposal facilities.
Before that time, the lab routinely dumped TCE and other volatile organic chemicals, which were used as solvents, into underground cesspools, a practice common in many businesses that used the chemical, such as machine shops, auto repair shops and dry cleaners.
David Storm, a toxicologist for the state Department of Health Services, said there was little concern about the disposal of volatile organic chemicals until the late 1970s because it was widely believed the chemicals would break down into harmless components before reaching the ground water.
But that belief was discarded in 1979 when significant quantities of the chemicals were found in ground water near an industrial complex in Azusa.
Concentrated in 2 Valleys
Since then, tests have shown that more than 150 wells throughout Los Angeles County are contaminanted with the chemicals. The contamination is mainly concentrated in the San Gabriel and San Fernando valleys, said Gary Yamamoto, Los Angeles district sanitary engineer with the state Department of Health Services.
He said ground water in both valleys is easily contaminated because of the areas' porous soils and shallow ground water fields.
In Pasadena, the contamination was first discovered in only one well, called Well No. 25, located a few hundred feet from JPL.
Within four years, concentrations of TCE had reached significant levels in another nearby city well, called Well No. 52, and two wells owned by the Lincoln Avenue Water Co.
The state tentatively has set a safe concentration level for TCE at 5 parts per billion, a level at which there would be one extra case of cancer if 1 million people drank the water for a lifetime.
Unsure of Safety Level
But Storm, of the state Department of Health Services, added that there may be no completely safe level of TCE contamination.