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r <br /> Ii 1 <br /> Site t <br /> Background Information West Clay Properties 5 <br /> a} Page 2 of 6 <br /> F' F , <br />' r iM IFI r y ! 4 e , V •• t , 4 tr ' ! r, n <br /> O [ctober 1999 - Seven soil borings (B-10 through B-16) were advanced to collect and analyze soil r <br /> samples, in addition, one soil sample collected from boring B-11 was analyzed for permeability, " <br />' porosity, total organic content and specific gravity, Petroleum hydrocarbon-impacted soil was <br /> detected in soil samples collected from all soil borings except B-13,the highest concentrations were <br /> detected in soil samples collected' from boring B-10, located adjacent to the former UST No 3 <br /> excavation <br />' July 2001 -An 8-hour step draw-down ground water extraction pilot test was conducted at the site 11 <br /> High concentrations of petroleum hydrocarbons were detected in extracted ground water samples <br />' November 2004 - Based on the results of the July 2001 pilot test, a 24-hour constant rate ground <br /> water extraction feasibility test was performed at the site Detected concentrations of target analytes <br /> in extracted ground water samples were significantly'lower than those reported for.the July 2001 <br />' pilot test <br /> i <br /> Ground Water Monitoring- Based on,analytical results of ground water samples collected during <br />' quarterly monitoring and site assessment activities, the lateral extent of impacted soil has been <br /> defined to the north, east and west However, the vertical extent of the contamination plume, as well <br /> as the lateral extent to the south, is not well defined <br /> 1 <br /> Cluster UST Area (North Area) <br />' December 1998 - Two 10,000-gallon-USTs and one 6,000-gallon UST were removed from a F <br /> common excavation at the site <br />' October 1999-AGE'advanced one soil boring(B-9)for collection of soil and ground water samples ' <br /> ' ;Significant concentrations of petroleum hydrocarbons, 1m were detected in samples collected frothe i <br /> boring Based on the,findings from boring B-9,monitoring wells'MW-9 and MW-10 were installed <br /> lip ` near'the former UST excavation area k , <br /> I I r r I <br />' July 2000 - Nine pilot borings were advanced at the site for installation of monitonng wells r <br /> MW-11AIB through MW-13A/B, air-sparging well AS-1 and ground water extraction wells EW-1 ' <br /> r and EW,2 Petroleum hydrocarbons were detected in soil samples collected from pilot borings EW-1 <br />' and MW-13B r <br /> I <br /> I I <br /> November 2002 - Four pilot borings were advancedat the site for installation of monitonng wells <br />' MW'14kB and MW-1 SAB Target analytes were not detected above laboratory reporting limits <br /> in the soil samples submitted for analyses <br />' December 2003 - Approximately 340 cubic yards'of petroleum hydrocarbon-impacted soil was 3 <br /> excavated from the former UST location' Soil was disposed of at Forward Landfill in Manteca, ; <br /> Advanced GeoEnvironmental,Inc <br /> t <br /> r <br />