SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

PUBLIe HEAL'T'H SE VICES SAN JOAQUIN COUNTY , ENVIRONMENTAL HEALTH DIVISION i Karen Furst, M.D., M.P.H., Health Officer 304 East Weber Avenue,Third Floor • Stockton, CA 95202 arae+ 209/468-3420 PAUL SUPPLE DEC 0 7 2001 ARCO PRODUCTS COMPANY P 0 BOX 6549 MORAGA CA 95470 RE: ARCO Station#4932 SITE CODE: 1136 16 E. Harding Way Stockton CA 95204 San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD) has reviewed the"Interim Remediation/Multi-Phase Extraction Feasibility Test Report"dated May 10, 2001 and the"Additional Site Assessment Report'dated November 9,2001 that were prepared by SECOR International Incorporated (SECOR)on your behalf and has the following comments. The Feasibility Test Report documents a multi-phase extraction (MPE)pilot test that took place the week of February 12-16, 2001. Please note that this report was submitted to PHS/EHD four weeks late. The objective of the MPE test, as stated in the work plan dated December 14, 2000, was to reduce the potential for further migration of dissolved hydrocarbons in groundwater, and to determine the long-term feasibility of using MPE as a remedial method for the site. In addition, the work plan proposed that laboratory analytical results of groundwater samples collected during the next quarterly sampling event following the test would be compared to the results of sampling events completed prior to the test to evaluate the effectiveness of using MPE to remediate the petroleum hydrocarbon contaminated groundwater at the site. The test was performed with a dual phase(soil vapor and groundwater)extraction system. The test was performed on groundwater monitoring well MW-4, soil vapor extraction well SVE-1, and a combination of both wells. During the week of the MPE test, PHS/EHD staff made several visits to the site to observe the progress of the test and to speak with the SECOR field staff monitoring the test. The technician on site informed PHS/EHD that a pumping test would be performed on MW-2 and MW-4 on Friday February 16, 2001. When PHS/EHD arrived at the site on Friday morning they were informed that the pumping test on MW-2 had been performed the afternoon before. The pumping test on MW-4 was performed on Friday as scheduled. However, the report fails to discuss either of these tests. The SECOR technician reported to PHS/EHD that neither well could sustain a pumping rate of even 0.5 gallons per minute. The California Code of Regulations requires responsible parties to compare at least two cleanup alternatives for their feasibility in mitigating the contamination and for their cost effectiveness. Since two different tests were performed at this site, two different tests should have been discussed in the report. The report concludes that MPE technology is a feasible remedial alternative for mitigating hydrocarbon-impacted soil at the site, but makes no comment about mitigation of the contamination in the groundwater. The report also made no comments on the concentrations of contamination in the groundwater in samples collected prior to the MPE test as compared to those collected after the MPE test. A Division of San Joaquin County Health Care Services