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PUBLIC TiEALTH SER\17CES <br /> SAN JOAQUIN COUNTY Z?° <br /> ENVIRONMENTAL HEALTH DIVISION a <br /> Ernest M. Fujimoto, M. D., M.P.H., Acting Health Officer <br /> 304 East Weber Avenue, Third Floor • Stockton, CA 95 <br /> 209/468-3420 t <br /> BRETT HUNTER JUN 0 3 1997 <br /> CHEVRON USA <br /> PO BOX 5004 <br /> SAN RAMON CA 94583-0804 <br /> Re: Ron's Chevron Site Code: 1039 <br /> 139 South Center <br /> Stockton CA 95202 <br /> San Joaquin County Public Health Services, Environmental Health Division(PHS/EHD)has completed <br /> review of the Blaine Tech"1st Quarter 1997 Monitoring Report"dated March 20, 1997 and your <br /> accompanying correspondence dated April 28, 1997. Your correspondence raised several issues <br /> regarding subsurface transport, remedial alternatives evaluation, intrinsic bioremediation monitoring <br /> parameters and groundwater monitoring requirements. PHS/EHD has prepared the following comments <br /> for your response. <br /> Subsurface Transport and Remedial Alternatives Evaluation <br /> An unauthorized release was discovered on April 5, 1990 when the former tanks were removed. <br /> According to the California Code of Regulations,Title 23,Division 3, Chapter 16 (Underground Storage <br /> Tank Regulations),Article 11 §2720,corrective action is defined as any activity necessary to investigate <br /> and analyze the effects of an unauthorized release; propose a cost-effective plan to adequately protect <br /> human health safety, and the environment and to restore or protect current and potential beneficial uses <br /> of water; and implement and evaluate the effectiveness of the beneficial uses of water and implement and <br /> evaluate the effectiveness of the activity(ies). Since the discovery of the unauthorized release, <br /> corrective action has been required. <br /> The data collected indicates that it is not premature to begin considering remedial alternatives. The <br /> Underground Storage Tank Regulations,Article 11 §2725(a) states that the soil and water investigation <br /> phase includes the collection and analysis of data necessary to assess the nature and vertical and lateral <br /> extent of the release and to determine a cost-effective method of cleanup. §2725(b)states that using the <br /> information obtained during the investigation,the responsible party, in this case Chevron, shall propose a <br /> Corrective Action Plan. §2725(d)states that the Corrective Active Plan shall include an assessment of <br /> the impacts, a feasibility study,and applicable cleanup levels. It is during the soil and groundwater <br /> investigation phase that remedial alternatives are evaluated. <br /> As you indicated, in correspondence dated July 22, 1996, the fuel hydrocarbons detected in soil at <br /> downgradient locations MW7 and S139 were measured in saturated samples and are most likely <br /> associated with the contaminant plume originating from the site. PHS/EHD made an agreement with you <br /> on December 1, 1995, after MW7 and S139 had been drilled,that Chevron would complete any additional <br /> work to define the extent of the plume by May 1, 1996. The additional well(s)have not been installed. <br /> It should be noted that PHS/EHD has directed Chevron to define the extent of the soil and groundwater <br /> contamination plume since 1990 when the unauthorized release report was filed. Chevron's last <br /> correspondence dated February 28, 1997 stated that the dissolved hydrocarbon plume was stable and not <br /> A Division of San Joaquin County Health Care Services <br />