Three years ago, when experts tested the first of 90 wells in the San Gabriel Valley that have been tainted by industrial pollution, they found a virtual chemical cocktail.
Tests at the well in Irwindale revealed large shots of perchloroethylene (PCE) and trichloroethylene (TCE) as well as liberal dashes of chloroform, carbon tetrachloride and other substances suspected of being weak carcinogens.
Not the kinds of things people want to find in their drinking water.
But now the well is producing water that is almost fit to drink.
Federal, state and local officials are baffled about just how and why that happened. They say the well's recovery is not a sign of progress but an accident. It just means the contamination has probably moved elsewhere.
May Take $800 Million
Equally confusing is the broader question of how to eliminate the ground-water pollution that permeates the San Gabriel Valley. The U.S. Environmental Protection Agency, which put the San Gabriel Valley on its Superfund list in 1984, has estimated that it may take $800 million and more than 50 years of work to clean up the water.
The problems at the Irwindale well illustrate the difficulties and frustrations facing those who want to clean up the ground water.
Consider, for example, that:
Officials have known that the Irwindale well has been polluted for more than eight years, but little has been done beyond shutting the well down.
The identity of the polluter remains a mystery despite years of investigation.
A $390,000 system has been installed at a nearby well to remove ground-water pollutants but is seldom used because of the operational expense.
Failure to remove pollutants has allowed the contamination to spread.
EPA officials say the problem is enormous because the contaminants are moving deep below the surface in large "plumes" within a huge water basin that stretches from Alhambra to La Verne and is the primary source of water for 1 million people.
Thus far, water companies have kept drinking water safe by drilling new, deeper wells in unpolluted parts of the basin and by blending slightly polluted water with purer water to meet drinking-water standards.
The problem surfaced more than eight years ago when technicians from Aerojet Electrosystems Co. in Azusa tested water at the Irwindale well on Morada Street. The well, which is 600 feet deep, was dug in 1961. The company ran the tests after its parent company, Aerojet-General Corp., had come under fire for contaminating soil and ground water with TCE at its plant at Rancho Cordova, near Sacramento. The amount of TCE in the Irwindale well, called the Morada well because of its location, was 360 times greater than the state's TCE limit. Aerojet is among a number of companies that EPA has investigated as potential sources of ground water contamination, but no formal accusations have ever been made against Aerojet or any other company.
Hank Yacoub, chief of the toxics section of the Los Angeles Regional Water Quality Control Board, said Aerojet notified his agency, which oversees the protection of ground water, about the Morada well on Dec. 23, 1979.
No one had ever tested local wells for TCE before, Yacoub said, and the situation was so novel that his first reaction was to look up TCE in a chemistry book.
The Morada finding prompted state health officials to order tests of other wells throughout the San Gabriel Valley, and then throughout the county as more TCE was found. By April, 1980, the Morada well and 36 others in the San Gabriel Valley had been shut down because their water contained more than 5 parts per billion of TCE.
A part per billion is the equivalent of one drop in a large swimming pool. State and federal officials limit the amount of TCE permitted in water to 5 parts per billion on the theory that long-term exposure at that level presents a cancer risk of no more than 1 in 1 million.
The Aerojet test showed that TCE in the Morada well had reached the extraordinary level of 1,800 parts per billion.
Later authorities began testing water for other compounds, such as PCE, which is widely used in dry cleaning.
Stan Yarbrough, general manager of the Valley County Water District, which owns the Morada well, said the district did not test the well again until recently and then obtained surprising results. Tests in March and April showed a dramatic drop in the strength of all contaminants.
But Yarbrough said the contaminants could easily reappear in subsequent tests or could be moving toward other wells.
The good news, Yarbrough said, is that the water district's 10,500 customers in Baldwin Park, Irwindale and neighboring cities have continued to receive pure water from the district's four uncontaminated wells.
But that is part of the problem, too, because the water district has no incentive to pump and treat polluted water while it has other wells that are clean. Yarbrough said treating polluted water costs money, which raises water rates.
Waiting for EPA