In early August, Frey Environmental conducted another vapor extraction project at the Pine Cove Market. The extraction, called an “over purge,” was limited to monitoring well no. 2 and lasted six hours.
The total petroleum hydrocarbon level was undetectable both before and after the over purge event, according to Oct. 10 results submitted to the Riverside County Department of Environmental Health.
Concentrations of both methyl-t-butyl ether (MtBE) and tert-butyl were not detected either before or after the test.
As a result, the report’s authors concluded, “Based on results of the current over purge event and results of previous soil groundwater investigations and remediation events at he site, FREY plans to prepare a site conceptual model and request no further action following the submittal of the third quarter ground water monitoring and sampling report.”
Some hydrocarbons, such as toluene, benzene and xylene were detected two weeks later during regular third quarter testing. While these recordings exceeded the maximum contaminant levels, they were only found in the monitoring well no. 2. None were detected in samples from the other six monitoring wells.
Total hydrocarbons and MtBE were undetected in any of the wells, not simply below the state maximum contaminant levels.