4th Polluted Well Closed in Downey

The city has closed a fourth municipal water well after detecting unacceptably high levels of contamination from an industrial solvent suspected of causing cancer.

The well was closed Aug. 18 after the dry-cleaning solvent tetrachloroethylene (also known as perchloroethylene or PCE) was detected at levels as high as 9.1 parts per billion, said Downey Water Supt. Greg Mayfield. The well, on city property that is part of the Rio Hondo golf course, was used primarily for irrigating the course.

The state requires water agencies to take action when PCE levels in water reach 4 parts per billion. That could mean closing the well or treating or blending the water to reduce the concentration of the contaminant.

The level of contamination found in the well would pose little danger to the public even if the well had not been closed, city and state officials said.

If a person were to drink two liters of water containing 4 parts per billion of PCE every day, the chance he would develop cancer would increase by less than one in 1 million, according to a senior sanitary engineer for the state Department of Health Services.

“The risk factor for getting in an automobile is subtantially higher than that,” said Public Works Director William A. Ralph.

The municipal water system provides tap water for about 75,000 customers in the city. The system gets more than 80% of its water from wells; the rest is purchased from the Metropolitan Water District of Southern California.

Ralph told the City Council last week about the closure. That contrasted with the way he handled closing the first three wells, which were contaminated by the same chemical.

At least three City Council members said they were surprised when a state official revealed in July that the wells had been closed in March and April. At the time, Ralph said there was no need to make a public announcement because the wells had been taken out of service and posed no danger to consumers. He said information on the closings was contained in records available for public review.

Ralph said he decided to publicly inform the council this time because contamination by even small amounts of potentially dangerous chemicals can stir strong public reaction. He said he would continue to keep the council and public informed on any closings related to contamination from toxic chemicals.

The city routinely shuts down wells for maintenance and repairs. Every few years a well is closed because of bacterial contamination and cleaned up, Mayfield said. The March closing was the first time a city well had been shut because of contamination from a suspected carcinogen.

“Rather than have people think we’re hiding information, which were not, we’re making every effort to show it all,” Ralph said.

Downey will notify water customers about the latest well closing both in the city’s bimonthly newsletter--the Downey Communicator--and with inserts in bimonthly water bills, said City Manager Don Davis.

“We will explain there’s no need to panic and we are going to provide quality water and we are correcting the situation,” he said.

City tests Aug. 5 turned up 9.1 parts per billion of PCE in water drawn from Well No. 21. Confirming tests were performed by the city and state Aug. 18, Mayfield said.

The Public Works Department closed the first three wells after PCE levels ranging from 6.7 parts per billion to 13 parts per billion were detected by state and independent tests. The contamination has not been linked to a specific source, officials said.

Under a state law that went into effect in 1985, the city and other water utilities are required to test periodically for dozens of organic chemicals commonly used in industry.

Downey draws its water from the Central Basin, a huge underground body of water that also supplies wells in other southeast Los Angeles County cities. Testing also has uncovered chemical contamination and forced well closings in South Gate, Santa Fe Springs, Bell Gardens and Bellflower, mostly during the past two years.

All of Downey’s 23 municipal water wells have been tested for actionable levels of PCE and trichloroethylene, or TCE, another contaminant found in the area. The results of tests for other chemical contaminants in 13 wells have not been completed, Mayfield said last week.

Those results should be ready shortly, and periodic testing will continue, he said.

Well No. 21 and one of the three that were closed previously have the largest capacities, and the city will work hardest to reopen them, Ralph said. Well No. 19, on Dolan Avenue south of Firestone Boulevard, is the other major well. Also closed are No. 17, on Pellet Street west of Old River School Road, and No. 20, on Adwen Street west of Old River School Road.

Well No. 21 primarily provided water to irrigate the golf course, while the other three wells supplied residential, commercial and industrial customers.

The city is buying more water from the MWD to replace the water from the closed wells. It costs the city $110 per acre foot to pump water, while the MWD charges $232 per acre foot, Mayfield said. An acre foot contains 325,900 gallons.

Increased costs could be passed on to consumers if the city must continue to buy more water from the MWD or the price of correcting the contamination problem is high.

“We’ve been able to absorb this so far without a rate increase,” Mayfield said.