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NATE C?F CALIFORNIA- Environmental Pro&n Agency PETE WILSON, Governor <br /> ' CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD "�\ <br /> CENTRAL VALLEY REGION <br /> 3443 Routier Road, Suite A hiEAi_Tl1 e z <br /> Sacramento,CA 95827-3098 E4VIRd�f IEN(AI. p <br /> PHONE: (916) 255-3000 ItiC"�! ,FRVICE �,'�� <br /> FAX: (916) 255-3015 <br /> 93 OCT -5 P99 2' 12 <br /> 24 September 1993 <br /> Mr. John Ewing <br /> Leprino Foods <br /> P.O. Box 173400 <br /> Denver,,CO 80217-3400 <br /> GROUND WATER ASSESSMENT PROPOSAL, LEPRINO FOODS, TRACY, SAN JOAQUIN <br /> COUNTY <br /> I have reviewed the 10 September Ground Water Assessment Proposal submitted by Kleinfelder for <br /> the Leprino Foods facility in Tracy. The proposal to conduct a ground water assessment using <br /> geoprobes prior to installing additional monitoring wells is acceptable, but the following comments <br /> must be addressed before any of the field work begins. <br /> 1. Soil samples should be collected for chemical analysis in the four proposed geoprobe locations <br /> surrounding the containment and excavated areas. At least one soil sample should be collected <br /> for chemical analysis at each of these geoprobe locations. This will help determine if the soil <br /> surrounding the excavated area is contaminated and acting as a source of hydrocarbons in the <br /> ground water. <br /> 2. If the soil or ground water sample from.the geoprobe immediately south of the excavated area <br /> (upgradient of EW-1) shows contamination, then a monitoring well should be placed there. <br /> Depending on these results, it may be necessary to further define the upgradient extent of <br /> contamination at a later date. <br /> 3. In addition to analyzing for TPH diesel, the geoprobe ground water samples also should be <br /> analyzed for TPH gasoline (TPHg), benzene, toluene, ethylbenzene, and xylene (BTEX). The <br /> ground water has never been sampled for these constituents, diesel fuel commonly has some <br /> small percentage of one or more of these constituents, and the drinking water standards for <br /> TPHg and benzene are very low. <br /> 4. It is necessary to allow at least 48 hours after well development before measuring ground water <br /> levels and collecting a ground water sample from the new monitoring wells. <br /> 5. Although free product is present in EW-1 and MW-1, the depth to water, depth to free product, <br /> and free product thickness in these wells should be measured at the same time as the ground <br /> water levels are measured in the new monitoring wells. These three parameters also should be <br /> measured in any of the new monitoring wells if free product is present. Ground water <br /> elevations can be calculated for wells containing free product using corrections for free product <br /> thicknesses. It will thus be possible to contour the ground water elevations using every <br /> monitoring well for each monitoring event, regardless of the presence of free product. <br /> N <br />