PCE contamination in some wells in South Lake Tahoe

Tetrachloroethen, better known as PCE, has been found in two municipal wells and three private domestic in the western portion of South Lake Tahoe according to the Lahontan Regional Water Quality Control Board.

They will be conducting an investigation to evaluate the spread of PCE in wells operated by Lukins Brothers Water Company. This is the first time the solvent has been detected in their wells so they were closed down immediately upon the discovery. The new detections may be related to drought conditions and a lowered water table according to Lisa Dernbach, senior engineering geologist for the Lahontan Water Board.

With only one clean municipal well left in operation, Lukins is receiving additional water supplies from the South Tahoe Public Utility District (STPUD). Ongoing testing has verified no residences or businesses are currently exposed to PCE levels above the drinking water standard of 5 micrograms per liter.

PCE is normally associated with dry cleaning activities, but the solvent compound can also be used for metal degreasing and is an ingredient in paint strippers. The compound is classified as a probable carcinogen that has the ability to increase the risk of cancer after consumption over many years. If PCE contact is made through the respiratory system or skin exposure, it can depress the central nervous system and increase the risk of Parkinson’s disease.

The investigation is being completed using $125,000 in grant money from the State Water Resources Control Board. During the week of Oct. 26, Lahontan’s consultant, URS, will be collecting groundwater samples from temporary borings.

“The public can expect to see a small drilling rig and support truck along residential streets between 5th and 11th streets for approximately five days,” said Dernbach. “Drilling will be moved every day, so the noise period will be short at each location. We appreciate everyone’s cooperation while we try to determine just how widespread this contamination problem is.”

Once the laboratory results for the samples are received, URS will compile a technical report and interpret the data. The report, due by the end of 2015, will be posted on the Lahontan Water Board’s website. If the results show more groundwater contamination than expected, a supplemental investigation may be proposed.

The Lahontan Regional Water Quality Control Board is a California state agency responsible for the preservation and enhancement of the quality of California’s water resources in eastern California. For more information about the Lahontan Water Board visit www.waterboards.ca.gov/lahontan/.