Past remediation efforts at the site of a previously leaking underground fuel tank in Idyllwild seem to have successfully removed most of the potential contaminants, according to a recent report filed with the Riverside County Department of Environmental Health.
In early October, R.M. Environmental, Inc., the consultants for property owner Sanden & Sons, Inc., of Mountain Center conducted soil analyses and detected virtually no hydrocarbon remnants.
“In summary, the findings of this investigation indicate additional soil remediation is not warranted for this site,” concluded Robert C. Manning, R.M. Environmental president, in the report’s cover letter.
Although some hydrocarbons, such as butyl benzene and naphthalene were detected, their concentrations were low. Neither benzene nor methyl-tertiary-butyl ethane (MTBE) was detected in any of the four locations.
As a result of these data, Manning’s reported concluded, “The soil vapor extractions conducted at the site significantly reduced the hydrocarbon compound concentrations of on-site soils through in-situ remediation. No significant hydrocarbon compound concentrations were detected in the soil samples.”
The soil vapor extractions were conducted in 2007 and 2008. The efforts removed more than 3,000 pounds of hydrocarbons. The extractions ceased in the spring of 2008 because the groundwater level was rising.
Since then the site and movement of the subsurface pollutants have been monitored with wells. In March 2012, Manning’s firm submitted a proposal to the DEH for permission to conduct the soil analyses. This was approved in June and the soil borings were taken in October.