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WA-rFRWORK CARP _ <br /> A RfSNA Company — <br /> 1 Environmental Solutions <br /> Through Applied Science, <br /> Engineering&Construcrio„ <br /> 1710 Main street t <br /> Escalon, CA 95320 <br /> Phone (209) 838-3507 1 <br /> Fax (209) 838-3509 September 13, 1991 <br /> Mr. Harlan Knoll <br /> San Joaquin County Public Health Services <br /> r Environmental Health Division <br /> P 0. Box 2009 <br /> Stockton, CA 95201 <br /> Re: Quarterly Monitoring Report, Heinz Facility, 757 East Eleventh Street, Tracy, CA <br /> Dear Mr. Knoll <br /> 0n July 10, 1991, groundwater monitoring was conducted at the above referenced site (Figure <br /> 1). During monitoring depth to water was measured, the wells were purged, and samples were <br /> collected from wells MW2 and MW3 <br /> Depth to water had dropped 0.3 to 0 5 feet since the previous quarterly monitoring and sampling <br /> f event in April, 1991 (Table 1) The gradient cannot be calculated specifically for this site <br /> because only two wells are accessible <br /> �•--�' <br /> asphalt <br /> halt (Monitoring well MWl has been paved over with <br /> p ) However, WaterWork currently monitors the uppermost saturated zone at three Tracy <br /> sites within a one-mile radius of the subject site <br /> The local groundwater gradient can be established from July 1991, monitoring data from 8181 <br /> Eleventh Street (Genstar Western Stone), 400 S Tracy Blvd , (Tracy Estates), and 6700 <br /> Granthne Road (J B. Terminal). The site locations and gradient directions relative to the s,ibject <br /> site are shown on Figure 2. The most recent groundwater gradient map and well logs for each <br /> site are included in Attachment 2 All the gradients are essentially in a northerly direction. <br /> There are no known surface or subsurface occurrences which would exert a significant influence <br /> on the direction of groundwater flow Therefore, even though the direction of flaw cannot be <br /> specifically determined from the on-site wells, the dir-ction can besafely assumed to be <br /> consistent with the nearby sites Monitoring well MW2 is appropriately located to monitor <br /> groundwater downgradient from the excavati:- and MW3 is adequate for upgradient <br /> observations. <br /> f <br /> The water samples collected from wells MW2 and MW3 were analyzed for benzene, toluene, <br /> e.hyibenzene, xylenes (BTEX), by EPA method 8020, total petroleum hydrocarbons as gasoline <br /> (T;'HG), and total petroleum hydrocarbons as diesel (TPHD) by modified EPA method 8015. <br /> Low levels of dissolved petroleum hydrocarbons were detected in both MW2 and MW3 Levels <br /> of benzene, toluene, ethylbenzene, and xylenes (BTEX) analytes detected are well below State <br /> �y <br />