The number of domestic wells in south San Luis Obispo contaminated with a toxic industrial solvent has grown to between 11 and 21 and those numbers could go even higher as a two-week-old investigation continues.
The exact number of contaminated wells is not known because two parallel investigations into the polluted wells are underway — one by state and county officials and another by two law firms representing about a dozen owners of contaminated wells. The two groups have not coordinated their testing or shared results with each other.
In the meantime, the source of the contamination has not been identified or whether it continues to leach into the wells. State and county health officials are recommending that people with contaminated wells use bottled water for cooking and drinking and install a carbon filtration system at their well head to filter out the pollutants.
While the source of the contamination has not yet been found, state water officials consider the nearby San Luis Obispo County Regional Airport a possible source. Chemicals found in the wells are associated with aviation and fuel. The airport is also at a higher elevation than the neighborhood with the polluted wells so pollutants would flow downhill from the airport to the wells.
Just before Christmas, county Environmental Health Services announced that five wells were contaminated with trichloroethylene or TCE, a chemical historically used as an industrial solvent and metal degreaser. All of the wells are in the area of Buckley Road, east of Davenport Creek Road and Evans Road.
Scott Milner, a county environmental health specialist, said an additional 37 wells were tested at the end of last month and six were found to be contaminated, bringing their total to 11.
The owners of those wells were notified of the contamination. The county is working with the Central Coast Regional Water Quality Control Board in testing the wells.
At the same time, two law firms specializing in toxic contamination also tested wells in the area and found 10 to be contaminated. They are sorting through their well tests to see if there are any duplications with the testing done by the two government agencies, but they do not have any results yet, said John Fiske, a lawyer with the San Diego-based firm Gomez Trial Attorneys.
“We have also taken an additional 20 samples that are being evaluated,” he said. “Based on the proximity of those wells to the ones we know are contaminated, we expect some of those to come back as contaminated as well.”
Fiske said he will share the results of that testing with government officials on Friday. Tim Moran, a spokesman with the State Water Resources Control Board, confirmed that they do not know which wells the law firms tested.
Fiske said his firm is publicizing its initial findings before sharing the results with state water officials because it doesn’t have a final number of wells as testing continues. But in the meantime, the firm wanted to get the word out to the affected neighborhood so people can get their wells tested and take any needed corrective action, Fiske said.
“It appears the results our clients are receiving from the water board are consistent with results we are finding,” he said.
TCE is not the only chemical found in wells in the area. County environmental health testing found an unhealthy level of toluene, a gasoline additive, in a well off Buckley Road, Milner said.
Testing done by the law firms also detected two other chemicals — a form of dichloroethene or DCE and tert-butyl alcohol or TBA. DCE is a chlorinated solvent that could be a breakdown product of TCE or a separate pollutant, Fiske said. TBA is a gasoline additive similar to toluene.
“These families have a right to clean water, and we are investigating whoever caused this contamination,” said Scott Summy, with the Dallas-based law firm Baron & Budd, which is working with Fiske’s firm to investigate the contamination. “This is a serious public health concern for the community because it appears that the plume may be larger than originally known.”
State water officials have sent a letter to airport managers asking for historical use of TCE at the facility. They have until Jan. 20 to respond.
“We are also doing a lot of outreach to residents of the area, both individually and we’ve sent out notices,” Moran said. “We will likely have a public meeting in early February.”
Once the source of the contamination is found, it is likely that lawsuits will be filed, Fiske said. The suits would be based on the reduction in property values the affected residences have experienced.