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k.h.' 08 September 2009 AGE -NC Project No. 03-1055 Page 6 of 19 pit); five additional USTs of undocumented size and unknown petroleum product content were discovered east of the initial excavation (under the sidewalk right of way) and removed. Significant petroleum hydrocarbon contamination was encountered during the UST removals and the excavations were expanded to remove excess contaminated soil. A soil sample collected from the northern portion of the common UST pit had reportable concentration of TPH-g of 460 mg/kg. Based on information available at EHD (Cambria - prepared Site Summary and Closure Path Recommendations, dated 01 November 1996) it appears this soil contamination was never abated. During excavation activities on 09 July 1993, two grab ground water samples (water #1 and water #2) were collected from the excavation. TPH-g and BTEX were reported in grab ground water samples at maximum concentrations of 34,000 gg/l, 3,200 µg11, 1,600 µg/l, 840 µg/1 and 4,300 µg11, respectively (American Consulting Remediation and Construction Inc. -prepared Tank Removal -Soil Sampling Report, dated 10 August 1993). Based on the information available at EHD, it does not appear hydrocarbon impact to ground water was addressed adequately in this area. • March 1995 - Two additional ground water monitoring wells were installed off-site to determine the lateral migration of petroleum hydrocarbon impacted ground water. The historical ground water flow direction for the Chevron investigation was northeast. Chevron 1y wells installed off-site depicted minor concentrations of dissolved hydrocarbons and fuel additives. • Quarterly ground water monitoring occurred from December 1992 until June 1996. TPH-g, benzene and MTBE were reported in ground water samples collected during monitoring events at maximum concentrations of 2,400 µg11, l l µg/I and 51 µg11, respectively (Cambria - prepared Site Summary and Closure Path Recommendations dated 01 November 1996). • May 1997 - FinaI site closure granted by EHD, no further action required. • December 2004 - Four soil borings were advanced for the collection of soil and grab ground water samples by AGE during a Phase 11 Site Assessment of the former Chevron site. A total of four soil samples were analyzed for petroleum hydrocarbon constituents. TPH-g were reported in soil sample B4-15 at 8.0 mg/kg; toluene and m,p-Xylene were reported in the soil sample B3-15 at concentrations of 0.010 mg/kg and 0.011 mg/kg, respectively. TPH-g were reported in all grab ground water samples at concentrations as high as 36,000 µg/1 in boring B4. BTEX compounds were also reported in all borings at concentrations as high as 400 µg11 benzene (BI), 770 µg/1 toluene (B2), 280 µg/l ethylbenzene (B1), and 2,160 µg11 xylenes (B2). MTBE was reported in the water samples collected from borings Bl and B2 at concentrations of 65 µg/l and 150 µg11, respectively. 1,2 -DCA was reported in the water sample collected from boring B1 at a concentration of 7.3 µg/L The lateral extent of dissolved benzene reported in grab ground water samples collected in 2004 at the closed Chevron site is depicted in Figure 13. Advanced GeeEnvironmental, Inc.