Laserfiche WebLink
t i <br /> ' GROUND ZERO ANALYSIS, INC. <br /> 1714 Main Street <br /> Escalon,California 95320 <br /> Telephone (209)838-9888 <br /> Facsimile (209)838-9883 <br /> April 11,2001 <br /> Ms Margaret Lagorio <br /> San Joaquin County Public Health Services <br /> Environmental Health Division <br /> 304 E Weber Ave, 3rd Fl <br /> Stockton, CA 95202 <br /> Subject First Quarter 2001 Groundwater Sampling Report, Knowles/Roek Property <br /> 102 South Wilson Way, Stockton, California(Figure 1) <br /> 1 Dear Ms Lagono <br /> ' Ground Zero Analysis, Inc (Ground Zero) has prepared this report to summarize activities during the first <br /> quarter 2001 at the subject site Groundwater related activities included monitoring groundwater elevations <br /> and sampling groundwater from monitoring wells MW 1 through MW 14 As requested by San Joaquin <br /> �. County Public Health Services Environmental Health Division (PHS/EHD), groundwater samples were <br /> also collected from vapor wells VW1 through VW6 Analysis consisted of total petroleum hydrocarbons <br /> as gasoline (TPHg), benzene, toluene, ethylbenzene and total xylenes (BTEX), 1,2 dichloroethane (1,2- <br /> DCA),ethylene dibromide (EDB), and gasoline oxygenate additives [methyl tert-butyl ether (MTBE), ethyl <br /> I ' tert-butyl ether (ETBE), di-isopropyl ether (DIPE), tertiary amyl methyl ether (TAME), tertiary butyl <br /> alcohol(TBA), methanol and ethanol] <br /> The soil vapor extraction system (VES) was not in operation during the first quarter 2001 The system <br /> was shut down pending direction from PHS/EHD with respect to the confirmation soil bonngs, and <br /> ' remedial effectiveness evaluation performed in February 2001 <br /> Two cone penetrometer test (CPT) borings were advanced, five soil borings were drilled and sampled and <br /> ' one additional monitoring well (MW 14) was installed during the first quarter The purpose of this work <br /> was to further define the vertical extent of contamination and to determine the current contaminant <br /> concentrations in vadose soil subsequent to the operation of the VES The results of this work are being <br /> ' submitted to PHS/EHD in a separate report of investigation <br /> I <br /> ' GROUNDWATER ACTIVITIES <br /> Groundwater Monitoring and Sampling <br /> Groundwater monitoring was conducted on March 6, 2001 Depth to groundwater was measured in wells <br /> • MW 1 through MW 14 and vapor wells VW l through VW6 and subtracted from the wellhead elevations to <br /> ' determine groundwater elevation A discrepancy when initially surveying the elevation of new well MW 14 <br />