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r ' 29 April 2005, �. : . AGE-NC Project No. 987044.0. Page 4 of 18 10. : ASSESSMENT OF'HYDROCARBON-IMPACTED SOIL AND GROUND WATER The following is a brief summary,of,site assessment activities:' ' . March•1998 - Six soil borings (B i through 136) and four ground water monitoring wells '(MW-1.through MW-4) were installed at the site to assess the lateral and vertical extent of impacted soil and groundwater.A totalof 23 soil samples and four groundwater monitoring 'well samples were collected during the investigation-and were submitted for laboratory analysis.Total petroleum hydrocarbons quantified as gasoline and diesel(TPH-g and TPH-d, I respectively) were- detected in analyzed soil samples at concentrations as high as . 580 -milligrams per kilogram. (Mg/kg);, dissolved TPH-g and TPH-d weredetected from ground water Inonitoring'well samples'at concentrations ranging as high as 2,400 gg/l.BTEX compounds were detected in selected'soil samples and ground water monitoring well ' sample sat concentrations as hi�as 32 mg/kg and 36µ8✓l,res ectivel .B oriiig locations are depicted in Figure 2 and analytical results of soil and ground water samples are.presented in Tables 3 and 4.A report of findings (Preliminary Investigation &Evaluation Report, dated ' 14 September 1998) was submitted by AGE to the'SJCEHD. - May 2000 - Three soil borings (B7, MW5 and MW6)were advanced at the site; two of the I boring's were completed as monitoring wells MW-5 and MW-6. TPH-g was detected in the . , i 15-foot soil sample analyzed from boring MW6 at a concentration of 330 mg/kg..TPH-d was detected in MW5,MW6,and B7 at concentrations as high as 140 mg/kg(MW6-15). BTEX compounds were detected in the 15-foot soil sample from MW6 at concentrations of 0.'094 mg/kg,`2:6.mg/kg, 8.7 mg/kg and 2.8 mg/kg, respectively. Boring locations are depicted in Figure 2 and analytical results of soil and ground water samples are presented in Tables 3 and 4. A'report of findings (Quarterly Report = Second Quarter 2000, dated 09,August 2000.) was sub"' itted by AGE to tlie SJCEHD. . _ ).'January, 2002 - Two soil.probe borings B8 and B9 were advanced utilizing a van:mounted ' Geoprobe 5400 equipped with 1.125-inch diameter probe rods with an-attached 2.15-inch ' • diameter soilaample'r,'vertically to depths'of 60 feet bsg: Grab ground water samples were collected from each probe boring using a Geoprobe hydropunch sampling assembly. The ` probe rods were advanced to-approximately 60 feet bsg..TPH-g was detected in the water . 'i samples'collected from B8'and B9 at'concentrations of.71 Pg/1 and 88 µg/1, respectively. ; TPH-d was detected in'the water'sample collected from B9 at a concentration of 140 µg11. Ethylbenzene and total xylenes were detected in the sample from B8 at concentrations of 12. gg/1 and 1.3 pg/l,respectively.Toluene,ethylbenzene and total xylenes were detected in.the !!" water sample collected from boring,B9 at concentrations of 0.62 µg11, 0:72 pg/1 and 43 pg/l; ' 'respectively. No other.analytes including benzene were detected of or above laboratory ' reporting limits in the grab ground water samples.analyzed.Boring locations are depicted in Figure 2-and analytical results of grab ground.water samples are presented in.Table 4.'A Advanced GeoEnvironmental,Inc. �" ',' , - . ' 1 i I - 1, " 4 ,•