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Cone Penetrometer Testing Report Addendum - May 2002 Geweke Land Development & Marketing 16 South Cherokee Lane, Lodi, California 1.0. INTRODUCTION At the request of Mr Dale Gillespie of Geweke Land Development & Marketing (GLDM), Advanced GeoEnvironmental, Inc (AGE), has prepared the enclosed cone penetrometer testing (CPT) report addendum for 16 South Cherokee Lane, Lodi, California The enclosed addendum addresses comments in the Central Valley Regional Water Quality Control Board (CVRWQCB) letter dated 24 April 2002 and proposes additional work at the site A copy of the CVRWQCB directive letter is presented in Appendix A The site setting is illustrated on Figure 1 Site structures, boring, monitoring well and CPT locations are depicted on Figures 1 and 2 2.0. COMMENTS 1 On 19 December 2001, Hydrocarbon odor was observed from the soil encountered in sail boring CPT-2 at approximately two to four feet below surface grade (bsg) No soil samples were collected and no photo-ionization detector readings were measured CPT-2 is located between the former underground storage tanks (USTs) and former dispenser islands AGE believes the odor may be . attributed to residual hydrocarbons in the soil from the product Imes formerly extending across the area of boring CPT-2 2. A total of nine grab ground water samples were collected from CPT-1, CPT-2 and CPT-3 and submitted for laboratory analysis Ground water samples were collected from CPT-1 and CPT-2 at depth intervals of 72 feet to 76 feet bsg(Hydrologic Unit 2 -HU2), 92 feet to 96 feet bsg(HU2) and 110 feet to 114 feet bsg (HU3), from CPT-1 at 130 feet to 134 feet bsg (HU3), and from CPT-3 at 76 feet to 80 feet bsg(HU2) and 110 feet to 114 feet bsg(HU3) Figure 4 illustrates the location and concentrations of water samples collected during the CPT investigation Total petroleum hydrocarbons quantified as gasoline(TPH-g)was detected in eight of the nine water samples collected from CPT-1,CPT-2 and CPT-3 at concentrations ranging from 60 nucrograms per liter(µgd)to 500µg11 TPH-g was detected in the deepest water samples collected from CPT-1,CPT- 2 and CPT-3 at concentrations of 60 µg/l, 180 µg/1 and 60 µg11, respectively The vertical extent of TPH-g-impacted ground water has not been defined at the site Benzene was detected only in the ground water samples collected within HU2 from boring CPT-2, at concentrations as high as 2 7 µg/1 Benzene was not detected in the ground water sample collected within HU3 from CPT-2, or in any other water samples collected during the investigation The vertical extent of benzene-impacted ground water has been defined Analytical results of the CPT grab ground water samples are summarnzed in Table 1