No Health Threat From Dioxane-Tainted Wells, Officials Say

State health officials cleared the way Wednesday for reopening nine wells that had provided drinking water to more than 100,000 Orange County residents before testing revealed traces of a potential carcinogen.

The amount of dioxane in the well water does not pose a health risk, the state Department of Health Services concluded after a series of tests. The wells provide drinking water for Newport Beach and parts of Costa Mesa and Fountain Valley.

“We feel there isn’t any significant risk to the public with the use of these wells,” said David Spath, chief of the division of drinking water and environmental management at the state Department of Health Services.

Cities and water districts had been forced to buy water from Northern California and the Colorado River after the wells were closed in January.

The chemical, used to stabilize industrial solvents, was inadvertently added to the water supply by the Orange County Water District during an ongoing process in which treated sewage is injected into the ground. The injections provide a buffer between fresh drinking water and salt water.

Little is known about the long-term health effects of dioxane, a man-made chemical that also shows up in foods such as shrimp, tomatoes and coffee, and household products such as shampoo, soap and baby lotion. Federal environmental officials have classified it a probable human carcinogen and the state recently deemed it a “contaminant of concern.” It is one of about 50 compounds that the U.S. Environmental Protection Agency has listed as new potential drinking water contaminants.

There are no federal or state testing requirements or limits for dioxane, but the state recommends closing water wells if it shows up at elevated levels. Dioxane has been found in ground water in the Silicon Valley and the San Gabriel Valley, but water officials believe Orange County is the first place along the coast where it has been discovered. In the other regions, industrial waste has contaminated water with the substance.

Of the Orange County Water District’s 230 wells in northern and central Orange County, 72 have been tested for dioxane so far. Ten--nine active and one inactive--showed trace levels of the chemical.

Although the levels of dioxane in the wells is far below the point at which the state recommends sealing off water supplies, officials decided to shut the nine active wells.

Since its four wells were shut Jan. 28, Newport Beach has spent about $300,000 on imported water. The city began reopening its wells Wednesday, said Dave Kiff, assistant city manager.

“We wanted the reassurance of the Department of Health Services that the levels of this chemical were below anything that should cause us concern as stewards of our community’s water,” he said.

Mesa Consolidated Water District, which serves Costa Mesa, reopened one of its three wells Wednesday, and plans to tap the other two as needed, said Diana Leach, general manager. The wells supply one-third of Costa Mesa’s drinking water.

Fountain Valley has no plans to reopen two wells that were closed by dioxane contamination, a city official said. The city’s other wells provide enough water to supply the city. “If we moved into the summer months and the demand was there, we would put the wells back in service,” said Bob Kellison, the city’s field services manager. “At this time, we don’t have to and we’d like to continue to monitor them.”

A 10th contaminated well that serves Irvine and parts of Tustin, Orange and Santa Ana Heights was already out of service when the dioxane was discovered.

The Orange County Water District has stepped up treatment of the sewage injections to ensure more dioxane isn’t added to the ground water. But the effort continues to cleanse the dioxane from the ground.

It will cost about $10 million over two years to build several ultraviolet light and peroxide treatment facilities to clean the water once it’s extracted from the ground.

Cities have also asked the district to reimburse them for buying extra imported water, an issue that a district committee will discuss next week, said district spokeswoman Jenny Glasser.