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i <br /> Z Z Z • <br /> r+f( o Z z <br /> DCSERVICES, INCORPORATED <br /> • MPDS-UN5886-02 <br /> March 22, 1997 <br /> 76 Products Company <br /> 2000 Crow Canyon Place, Suite 400 <br /> P O Box 5155 <br /> San Ramon, California 94583 <br /> Attention Mr Adadu Yemane <br /> RE Quarterly Data Report 1N',Gtr <br /> Unocal Service Station #5886 <br /> 2701 West March Lane <br /> Stockton, California <br /> Dear Mr Yemane <br /> This data report presents the results of the most recent quarter of monitoring and sampling of the <br /> monitoring wells at the referenced site by MPDS Services, Inc <br /> RECENT FIELD ACTIVITIES <br /> The monitoring wells that were monitored and sampled during this quarter are indicated in Table 1 <br /> Prior to sampling, the wells were checked for depth to water and the presence of free product or sheen <br /> The monitoring data and the ground water elevations are summarized in Table 1 The ground water <br /> flow direction during the most recent quarter is shown on the attached Figure 1 <br /> Ground water samples were collected on March 7, 1997 Prior to sampling, the wells were each purged <br /> of 9 5 gallons of water During purging operations, the field parameters pH, temperature, and electrical <br /> conductivity were recorded on the purging/samplmg data sheets which are attached to this report Once <br /> the field parameters were observed to stabilize, and where possible, a minimum of three casing volumes <br /> were removed from each well, samples were then collected using a clean Teflon bailer The samples <br /> were decanted into clean VOA vials and/or one-liter amber bottles, as appropriate, which were then <br /> sealed with Teflon-lined screw caps, labeled, and stored in a cooler, on ice, until delivery to a state- <br /> certified laboratory MPDS Services, Inc transported the purged ground water to the Unocal Refinery <br /> located in Rodeo, California, for treatment and discharge to San Pablo Bay under NPDES permit <br /> ANALYTICAL RESULTS <br /> The ground water samples were analyzed at Sequoia Analytical Laboratory and were accompanied by <br /> properly executed Chain of Custody documentation The analytical results of the ground water samples <br /> collected to date are summarized in Table 2 The concentrations of Total Petroleum Hydrocarbons <br /> (TPH) as gasoline, diesel, and benzene detected in the ground water samples collected this quarter are <br /> shown on the attached Figure 2 Copies of the laboratory analytical results and the Chain of Custody <br /> documentation are attached to this report <br /> 2401 Stanwell Drive Suite 400 Concord CA 94520 <br /> TEL (510)602 5120 FAX (5 10) 689 1918 <br />