Laserfiche WebLink
PUBLIC HEALTH SERVICES COX.— ..CO <br /> SAN JOAQUIN COUNTY <br /> ENVIRONMENTAL HEALTH DIVISION <br /> Karen Furst, M.D., M.P.H., Health Officer <br /> 304 East Weber Avenue, Third Floor • Stockton, CA 95202 <br /> c4�iFoaN�c <br /> 209/468-3420 <br /> APR 0 3 2001 <br /> To: Mike Infurna, Senior REHS ORIGINAL <br /> From: Dot Lofstrom, RG FILE C <br /> Re: 2103 Country Club Boulevard, Stockton, CA(Former Chevron) <br /> 2081 Country Club Boulevard, Stockton, CA(Kwikee Foods) <br /> I have reviewed the site history and files for the former Chevron station located at 2103 <br /> Country Club Boulevard as well as the site history and files for Kwikee Foods located at <br /> 2081 Country Club Boulevard. Evidence has been presented that would indicate that <br /> some of the groundwater contamination located beneath the Kwikee Foods site may not <br /> be emanating from that site,but instead may be migrating from an off-site source, <br /> specifically, the former Chevron Station. Soil samples collected from the former <br /> Chevron Station have a detected concentration of up to 5100 mg/kg soil, whereas soil <br /> samples collected from the Kwikee Food site are primarily non-detect. However, it <br /> should be noted that the soil samples from the Kwikee food site were collected at greater <br /> depths when compared to the former Chevron Station. It appears that the soil samples for <br /> the Kwikee Foods site were primarily collected from the fine-grained unit below the <br /> coarse sand, and the lack of petroleum contamination could simply be a result of <br /> collecting below the water-bearing zone. Indeed, the one sample from the Kwikee Food <br /> site that did have a concentration of petroleum hydrocarbon contamination was collected <br /> at 15 feet below ground surface (bgs), compared to the other samples, which were <br /> collected at 20 or 25 feet bgs. Nonetheless, the overall soil results indicate a greater <br /> concentration of petroleum hydrocarbons in the soil at the former Chevron station when <br /> compared to the soil at the Kwikee Food Site. <br /> Representatives from both sites have presented the direction of groundwater flow as <br /> evidence that the source of groundwater contamination is not associated with their <br /> respective sites. Direction of groundwater flow has been presented as flowing <br /> consistently to the north/northeast. However, earliest data compiled in June 1992 for the <br /> former Chevron site suggest a southwest direction of groundwater flow. Moreover, <br /> groundwater gradient in the area is essentially flat, and direction of flow is based on data <br /> that vary by as little as one hundredth of an inch. Therefore,while direction of <br /> groundwater flow cannot be dismissed as an argument, it cannot be used as primary <br /> evidence. <br /> A third piece of evidence is the pattern presented by isoconcentration contour lines. The <br /> pattern of the isoconcentration lines suggests an earlier southwest direction to <br /> groundwater flow, which has later changed to a northeasterly direction. Although <br /> A Division of San Joaquin County Health Care Services <br />