NORWALK — State officials say a contaminated well here poses a "minimal" health risk for residents, although the officials acknowledge they have no idea how long the well contained three toxic chemicals before it was shut down in February at the request of the state.
The toxic chemicals in the well, owned by the Southern California Water Co., were discovered by coincidence by state health officials who were testing the well for the chemicals for the first time as part of a larger investigation of a known toxic waste site less than a mile away.
Environmentalists contacted by The Times said that the extent of the health risk is unknown but that the well contamination is part of a growing problem in the area.
"This is an issue in Southern California of crisis proportions that is not being dealt with in any comprehensive way," said Greg Karras, a research associate for the San Francisco office of Citizens for a Better Environment, a nonprofit, nationwide group.
Karras said that more than 100 wells in the Los Angeles area have been found to be contaminated with suspected carcinogens. The figure was confirmed by state officials, who said a majority of the wells have been shut down, but that water from some is being treated or mixed with water from other wells to meet safety standards for drinking water.
Well Closed Feb. 15
The well on Leffingwell Road pumped more than 18 million gallons of water into Norwalk homes and businesses during the first seven weeks of this year before it was shut down Feb. 15 at the request of the state Health Services Department.
The well was closed after state tests determined it contained 28 times the acceptable safety level of 1,1-dichloroethylene, a colorless, toxic chemical that is a suspected carcinogen.
The well last year supplied 7% of the water used by more than 25,000 customers in the southwestern part of Norwalk, water company officials said. No figures are available for this year. (Various companies and the city supply water to the rest of the community, which has 86,000 residents.)
No complaints have been made about any ill effects from the water, said city and state officials. The cause of the contamination is unknown, state officials said.
Besides dichloroethylene, two other toxic chemicals were discovered in the water in tests conducted this month, state officials said. The concentration of the two other chemicals, trichlorethylene and perchloroethylene, however, were below state safety standards for drinking water, state officials said.
Probe of Neville Chemical
The tests conducted on the well this month were the first test ever for approximately 40 organic chemicals. The tests were part of the state's investigation of the nearby Neville Chemical Co., which is ranked 28th on the state's list of worst toxic waste sites. State officials say the chemicals found at the well were not found at the Neville site and that they do not know where the chemicals came from.
State officials would not have tested the well for these organic chemicals were it not for its proximity to Neville, which is less than a mile away. While the state is required by law to test public water supplies every three years for toxic metals such as mercury and a group of six pesticides, the state is not required to test for organic chemicals such as dichloroethylene, said state officials.
The three chemicals found in the Norwalk well are industrial solvents used primarily for degreasing purposes, state officials said.
Risk Called 'Minimal'
The presence of the chemical 1,1 dichloroethylene in the water poses a "minimal" health risk to the mostly residential customers who drank water supplied by the well, Gary Yamamoto, a state senior sanitary engineer said Tuesday in an interview.
The official said the state decided to request closing of the well after water company officials indicated they could get along without it, Yamamoto said. He added that state officials decided not to expose the public to a minimal health risk if the water company did not need the well.
He said that if a water shortage requires the company to request that the well be reopened, the state would require the company to notify all customers in writing. The customers would have to be told of the contamination and advised either to boil the water to dispel the chemical or to drink bottled water, Yamamoto said.
Company officials said they plan to monitor contamination in the well, but that they do not anticipate having to use the well this year.
Based on state guidelines for dichloroethylene, Yamamoto estimated that if a million persons drank 2 liters (about 2.1 quarts) a day of the Norwalk water for 70 years, 28 persons would contract cancer from the water.
However, a toxicologist from Citizens for a Better Environment said the state standards do not consider the effect of dichloroethylene combined with the two other chemicals found in the water, or the effect when combined with other chemicals that may be in the water and environment.