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.**, 20 October 2004 AGE-NC Project No. 95-0184 Page 2 of 4 Water Basin (Basin 5-22). This basin is drained primarily by the San Joaquin River. The nearest surface water feature in the vicinity ofthe property is the Little Connection Slough immediatelywest of the subject property.Ground water is considered to be of beneficial use and is used for domestic, industrial and commercial purposes. UNDERGROUND STORAGE TANK REMOVALS On 24 April 1987,one 1,000-gallon gasoline underground storage tank(Tank A)was removed from the northwestern corner of the site.One 1,000-gallon gasoline UST and one 1,000-gallon diesel UST (Tanks B&C)were removed from beneath the sidewalk at the southeastern corner of the site on 25 May 1990. Petroleum hydrocarbons were detected in soil samples collected beneath tanks A, B and C. On 19 October 1988, one 300-gallon waste oil UST (Tank D) was removed from the site near the northern property line and the canopy. Only low concentrations of TCE and chloroform were detected in the sample collected beneath the UST. SITE ASSESSMENT ACTIVITIES An initial subsurface assessment was performed by WaterWork Corporation. One soil boring was advanced to a depth of approximately 35 feet below surface grade(bsg)near tank A. Ground water was encountered at 32 feet bsg. Details of the initial investigation were summarized in the WaterWork-prepared Preliminary Assessment Report dated 12 January 1990. Five soil borings(B 1 through 135)were drilled at the site by Geological Audit Services,Inc.between 11 and 14 February 1994.Borings B 1 through B4 were completed as ground water monitoring wells MW-1 through MW-4,respectively.Free product was encountered in MW-4 and removed between September and November 1994.Total petroleum hydrocarbons quantified as gasoline(TPH-g)and volatile aromatics(benzene,toluene,ethylbenzene and xylenes;BTEX)were detected in each well. TPH as diesel (TPH-d) was detected in MW-4. From 19 to 26 February 1996, six borings were advanced at the site by AGE. Boring MW-7 was advanced to a depth of 60 feet and was completed as a ground water monitoring well.Boring VW-1, drilled at an angle of 30° from vertical directed N 34`E,was advanced to a vertical depth of 55 feet bsg with a horizontal run of 31.8 feet and was backfilled to surface grade.Borings VW-2,VW-3 and VW-4 were advanced vertically to a depth of 55 feet and were completed as vapor extraction remediation wells(VW-2 double-completed).Boring VW-5,drilled at an angle of 10° from vertical directed N 80° W, was advanced to a depth of 55 vertical feet bsg with a horizontal run of 9.7 feet and was triple-completed as a vapor extraction remediation well. Petroleum hydrocarbons were detected in each boring at concentrations as high as 23,000 mg/kg (milligrams per kilogram, equivalent to parts per million, ppm; VW5 at 15 feet). Advanced GeoE.,h onwnlal,Inc.