All’s not well
Source of chemicals in south Chico ground water a mystery
After more than 40 south Chico families were warned last week against further use of their tap water, state officials launched an investigation into the startling discovery of chemical contamination in private wells.
Officials in the state’s Regional Water Quality Control Board were stunned by the results of November tests that show that wells used by residents of Skyway and Cessna avenues off Hegan Lane (see map) were contaminated by a dangerous chemical solvent.
In 10 wells in the unincorporated neighborhood, the amount of TCE (trichloroethylene)—an organic solvent used in degreasing operations and aviation—was above the maximum permitted by state and federal drinking-water standards. Thirteen wells had amounts above the higher water-quality standard, known as California’s “public-health goal,” for drinking water.
The Butte County Environmental Health Department advised families in the neighborhood to avoid using tap water for drinking, bathing or even unventilated clothes washing. The state’s inadvertent TCE discovery complicates Chico’s already considerable groundwater contamination problems.
Using the more sensitive of the two testing methods the regional water board employed, TCE was detected in 25 of the 40 Skyway Homes subdivision wells sampled, although in most cases it was below the five micrograms per liter limit set by state and federal drinking-water standards. Meanwhile, the state water board in Sacramento says on its Web site that it’s seeking a new “focus area” for domestic water-well testing. The board’s Voluntary Domestic Well Assessment Project was designed to improve the quality of drinking water coming from domestic wells, and is explained at: http://www.swrcb.ca.gov/cwphome/land/gama/voluntary.htm
Someone must have discharged “quite a bit” of TCE to have traces show up in the groundwater, said Karen Clementsen, a senior geologist in the water board’s Redding office, suggesting there has been an unreported spill or illegal dumping at some point. “There must have been a higher concentration on the ground somewhere,” she said.
The water board wants to know where the spill or dumping occurred and was working on a report outlining recommendations for further action when the News & Review went to press.
The water board’s regional office agreed to conduct comprehensive testing on 40 wells in November, several months after neighborhood residents of the industrial area said they were worried about petroleum-product contamination to their water supply from the tank farms to the north.
The Kinder-Morgan tank farm has leaked petroleum products into the groundwater at its site, and south Chico residents have been concerned about whether that’s created a moving plume. Officials have identified other TCE plumes—the most widely known created by Victor Industries and running from Fair and 20th streets to Dayton Road.
But the regional water board identified a new contamination problem when it conducted tests using the drinking-water analysis recommended by the Environmental Protection Agency at a cost of $19,000.
“First we had to find the funds for the contract,” said Clementsen. “We were looking for petroleum products. When we saw TCE, we were definitely surprised.”
TCE enters the body primarily through vapors and can affect the central nervous system. Prolonged, intense exposure to TCE can cause cancer.
Two wells were contaminated with another chlorinated solvent, PCE, or tetrachloroethylene, in amounts higher than public-health-goal standards but lower than the maximum allowed by state and federal regulations. Further tests are also being conducted to confirm the suspected presence of small amounts of methanol.
Clementsen said that she and other officials personally telephoned each household the same day they received the test results. Given that the tests were conducted on an unregulated water supply, Clementsen doubts that any such comprehensive testing had been done before by a governmental agency.
Meanwhile, the Environmental Health Department issued a Dec. 16 press release to comply with the state’s public notification law.
Butte County Director of Environmental Health Vance Severin doubted that the exposure was enough to be considered an “acute hazard.”
“But let’s face it,” he said, “we don’t want people to be drinking TCE, particularly sensitive populations. We don’t want to gamble. TCE is about as bad an actor as there is out there.”
TCE worries officials because it doesn’t degrade quickly and is mobile.
Severin said he had no reason to think the petroleum tank farms of southwest Chico were responsible for the contamination. Officials will look at an array of possibilities, including an old airstrip in the area.
Other south Chico residents were asking for well testing and wondering whether the TCE has moved from the Skyway Homes subdivision. Clementsen agreed that the contaminant’s mobility is a concern and said officials would soon begin testing wells immediately to the east and west of the “hot spots” that were found in the middle of that neighborhood.
But she warned that she doesn’t foresee widespread well testing in south Chico. The regional office has already spent 36 percent of a $52,000 annual budget on the November tests. That figure represents the board’s entire budget for regulatory work in a geographical area that encompasses parts of seven counties.
Public officials noted that homeowners on private wells not connected to a public water service are generally responsible for their own water testing.