ARCHIVED REPORTS XR0006063 - Laserfiche WebLink

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{ y GROUNDWATER MONITORING Groundwater Levels On July 11, 1995, Apex personnel collected groundwater-level measurements from all six wells All groundwater elevations were measured to the nearest 0 01 foot, referenced to the surveyed top-of-casing elevations, and conducted according to the Apex standard operating procedures (SOP)included as Attachment 1 Liquid-level measurements collected since January 1993 are summarized in Table 1 Figure 3 is a potentiometric surface map of the shallow water-bearing zone on July 11, 1995 Groundwater Samohn2 and Analysis On July 11, 1995,Apex personnel collected groundwater samples from all six monitoring wells (MW-1B, MW-2 through MW-6) The samples were submitted, under chain-of-custody,to Sparger Technology, Inc , of Sacramento, California, a state-certified analytical laboratory All samples were collected according to the Apex SOP included in Attachment 1 Analytical results since January 1992 for total petroleum hydrocarbons(TPH), as gasoline, and benzene, toluene, ethylbenzeue and total xylenes(BTEX) are summarized in Table 2 The laboratory analytical reports and cham-of-custody form are included in Attachment 2 All six groundwater samples were below laboratory detection limits for TPH, as gasoline, and below laboratory detection limits for BTEX REMEDIATION On December 6, 1994, a soil vapor extraction system consisting of an R S I SAVE system was installed at the subject site The vapor extraction system was installed per San Joaquin Valley Unified Air Pollution Control District Permit conditions The vapor extraction system consisted of an internal combustion engine with catalytic converters mounted on the exhaust The system was started on December 6, 1994, and after adjustments,has been operated continuously since December 13, 1994 During this reporting penod, soil vapor flow to the system has vaned from 43 cubic feet per mmute (CFM) on January 24, 1995, to 15 CFM on March 7, 1995 The initial vapor extraction rate was 16 standard cubic feet per mmute(SCFM) Based on a vapor sample analytical results on February 21, 1995, the system extraction rate was 0 23 pounds per clay(1b /day) as gasoline Benzene was not detected and petroleum constituent discharge rates were essentially zero System operating data calculations are contained in Attachment 3 2