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Chuck Carmel Page 4 <br /> The need for a groundwater investigation at this site was also discussed at the meeting. The <br /> laboratory results showing contamination at a depth of 45 feet BGS in B43/VW-5 (and to varying <br /> depths in other borings), the field observations and PID readings indicating contamination to depths <br /> of approximately 59' BGS, the sandy porous soil underlying the site and the seasonal high depth to <br /> groundwater of approximately 40' BGS indicate the need to verify that groundwater has not been <br /> impacted at this site. A proposal to include the installation of monitoring wells during the next phase <br /> of field work can be done by way of an addendum to the work plan. <br /> Facility 6080 at 85 & Louise, Lathrop <br /> PHS/EHD contact - Linda Turkatte <br /> Discussed at the meeting was the issue of the contamination that was detected in the groundwater <br /> sample recently collected from the area of the former waste oil tank at this site. The accuracy of <br /> groundwater results using a hydropunch-type instrument (as was the case for the collection of this <br /> groundwater sample) versus using a conventional monitoring well was discussed. Documentation was <br /> mentioned of case studies showing a close relationship between the two sampling methods. PHS/EHD <br /> will review these case studies if they are submitted. However, regardless of the method used to obtain <br /> the sample, it did show contamination in the groundwater, as "miscellaneous" hydrocarbons. <br /> More information is needed from this site before a determination can be made as to any future work <br /> needed or if closure is warranted. Additional information that would be helpful are the type or types <br /> of hydrocarbons present (possibly through use of additional analytical methodologies), the source of <br /> these hydrocarbons (as there may be other possible sources located at the site) and the full extent of <br /> these hydrocarbons in the groundwater. Any information on the former gasoline tanks that were <br /> removed before 1984 would also be helpful and should also be submitted to PHS/EHD. This <br /> information is needed for PHS/EHD to make an effective evaluation of the groundwater quality at <br /> this site. <br /> Although not discussed at the meeting, PHS/EHD recommends that the existing monitoring wells at <br /> this site be sampled at least on a yearly basis. <br /> It was suggested that all parties meet again in three months to maintain consistency and <br /> communication.PHS/EHD will be pleased to schedule Wednesday, June 30, 1993 for the purpose of <br /> following up the March 30th meeting. <br /> Please contact Margaret Lagorio, (209) 468-3449 or Diane Hinson, (209) 468-3452 of my staff to confirm the <br /> tentative date. <br /> Jogi Khanna, M. , M.P.H. <br /> Health Offi <br /> urie AdCo�EHS, Program Manager <br /> Environmental Health Division <br /> LAC/ML:lb <br /> c: H.C. Windsor c: J. Bobbitt <br /> c: K. Christie c: J. Johnson <br /> c: J. Lucas c: E. Thayer, CVRWQCB <br />