SITE INFORMATION AND CORRESPONDENCE 1988 - 2001

Home Browse Search

Environmental Science & Engineering,Inc. A CILCORP Company S3)L")E,, 2a Pi12: 58 December 19, 1995 Mr. Michael Infurna San Joaquin County Health Services Department of Environmental Health P.O. Box 2009 Stockton, California 95201 SUBJECT: REQUEST TO DISCONTINUE INTERIM PUMPING FORMER DELTA TRUCK 3535 E. CHEROKEE ROAD, STOCKTON, CALIFORNIA SITE CODE 1800 FSE PROJECT 6925400 Dear Mr. Infurna: Environmental Science & Engineering, Inc. (ESE) has been providing oversight of the interim remediation at the subject site since 1993. The interim remediation has consisted of periodic pumping of ground water from well UST-1. Ground water monitoring wells (UST-2 through UST-4) installed in the area of UST-1 show that the hydrocarbon plume is relatively small in size and is localized in the vicinity of UST-1. Over the last two years, the concentrations of hydrocarbons have steadily decreased. Most recently, over the last two quarters of sampling, the concentration of total petroleum hydrocarbons as diesel (TPH-D) has remained steady at approximately 100 parts per billion and the gasoline constituents (TPH-G and BTEX) have decreased below method detection limits. We believe it is time for the method of periodic ground water pumping to be discontinued. Although it appears that the TPH-D concentration has reached a limit using the method of ground water pumping, this observation will need to be evaluated as the relatively high ground water levels begin to lower in 1996. We believe that ground water needs to be allowed to re- equilibrate in order to estimate the effect of hydrocarbon leaching from soils. ESE believes that an alternative remedial technology should be employed to further remediate the residual hydrocarbons at this site. Ground water pumping has been demonstrated elsewhere to not be economically beneficial (LLNL, 1995). Over the next three to four quarters, ESE would like to investigate cleanup alternatives and study at least two cost-effective technically feasible cleanup alternatives for corrective action of the source area and ground water. It is ESE's understanding that one of two corrective action methods (Article 11 of the Corrective Action Program) will need to be proposed as the method of choice. The schedule of these feasibility studies will be presented to you during the first quarter of 1996. Reference: Lawrence Livermore National Laboratory, 1995 Recommendations To Improve the Cleanup Process for California's Leaking Underground Fuel Tnaks (LUFT's), UCRL-AR-121762, October 16, 1995. 4090 Nelson Avenue,Suite J Concord,CA 94520 Phone(510)685-4053 Fax(51.0)685-5323