Dry cleaning solvent found in Tahoe wells
October 24, 2015
An investigation into how a dry cleaning solvent turned up in South Lake Tahoe wells is being conducted by the Lahontan Regional Water Quality Control Board.
Investigators will be examining the spread of tetrachloroethene, after the solvent compound was detected in two municipal wells and three private domestic wells in the western portion of the city.
The municipal wells, operated by Lukins Brothers Water Co., did not have a history of contamination and were closed down immediately upon the discovery. The new detections may be related to drought conditions and a lowered water table.
With only one clean municipal well left in operation, Lukins is receiving additional water supplies from the South Tahoe Public Utility District. Ongoing testing has verified no residences or businesses are currently exposed to PCE levels above the drinking water standard of 5 micrograms per liter.
While the compound is normally associated with dry cleaning activities, it 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 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. Next week Lahontan's consultant, URS, will be collecting groundwater samples from temporary borings.
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"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 Lisa Dernbach, a senior engineering geologist for the Lahontan Water Board. "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.