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' Laboratory analysis of grab water samples detected First Water Zone fuel-impact (TPH-g,
<br /> iTPH-d,BTEX,MTBE,TBA and 1,2-DCA constituents)from P-7,Second Water7.one fuel-
<br /> impact(TPH-g,TPH-d,BTEX and 1,2-DCA)from P-5,P-7,P-8 and P-9,Third Water Zone
<br /> fuel-Impact(TPH-g,TPH-d,benzene and 1,2-DCA)from P-8 and P-10, and Fourth Water
<br /> Zone fuel-impact (TPH-g, TPH-d and BTEX) from P-5, P-6 and P-8 A report of findings
<br /> ' (Cone Penetrometer Testing (CPT) Site Investigation - Third Quarter 2001, dated 21
<br /> October 2001) was submitted by AGE to the S3CEHD
<br /> • July through September 2003-AGE Installed six multi-level ground water monitoring wells
<br /> (MW-8 through MW-12) to depths of approximately 125 feet bsg at the site to assess the
<br /> vertical extent of petroleum-impact AGE generally utilized four of the seven multi-level
<br /> ' chambers and Installed screen Intervals at depths between 35 and 45 feet bsg (First Water
<br /> Zone),65 and 75 feet bsg(Second Water Zone),95 and 100 feet bsg(Third Water Zone),and
<br /> between 120 and 125 feet bsg (Fourth Water Zone) Soil samples collected from MW-8
<br /> ' detected significant TPH-g,TPH-k and BTEX at 20 feet bsg,lesser concentrations of TPH-g,
<br /> BTEX and 1,2-DCA were detected from MW-8 at depths of 35 feet and 65 feet bsg, low
<br /> xylene concentrations were detected from MW-12 at 50 feet and 80 feet bsg No constituents
<br /> ' of concern were detected in the initial water samples collected from multi-level wells MW-8
<br /> through MW-12 Results of the multi-level well Investigation were reported in Multi-Level
<br /> Monitoring Well Installation Deport- Third Quarter 2003, dated 24 March 2004,prepared
<br /> ' by AGE
<br /> ' Between December 1999 and March 2004, seventeen ground water monitoring events were
<br /> performed at the site to monitor dissolved petroleum hydrocarbon concentrations in ground water
<br /> and to characterize ground water flow direction and gradient on the site Generally, petroleum-
<br /> impacted ground water was generally detected from wells MW-1 and MW-7 at concentrations as
<br /> high as 67,000 µg/1 TPH-g, 6,200 gg/l TPH-d, 16,000 µg11 TPH-K, 27 µg11 MTBE, 1,200 µg/1
<br /> 1,2-DCA and various BTEX compounds as high.as 14,000µg/1 benzene No constituents of concern
<br /> ' were detected from multi-level wells MW-8 through MW-12
<br /> Generally,the depths to groundwater in wells MW-1 through MW-12 vaned between 25 and 35 feet
<br /> ' bsg, ground water elevation at the site was calculated to be between approximately between 12 and
<br /> 22 feet below mean sea level The general ground water gradient at the site was calculated to be
<br /> approximately 0 003 ft/ft or approximately 16 feet per mile and generally directed towards the east-
<br /> northeast
<br /> 5 0 REGIONAL GEOLOGIC SETTING
<br /> The property Is situated within the Great Valley Geomorphic Province of California, a large,
<br /> ' elongate, northwest trending, asymmetric structural trough The Great Valley Province has been
<br /> filled with thick sequences of sediment ranging in age from Jurassic to Recent,creating a nearly flat-
<br /> lying alluvial plain,extending from the Tehachapi Mountains in the south to the Klamath Mountains
<br /> in the north The westem and eastern boundaries of this province are comprised of the California
<br /> Advanced GcoEnvironmental,Inc
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