ARCHIVED REPORTS_XR0004023 - Laserfiche WebLink

Home Browse Search

L • Mr Travis Bryant November 2, 2001 Page 2 Project No 2002-1426-01 In the vicinity of the site are a former ARCO Service Station, a Chevron Service Station, a Texaco Service Station, The Transmission Shop, and a former Colombo Bakery, all of which have or previously had USTs Based on data collected from subsurface investigations performed at the former ARCO Service Station, the Chevron Station, The Transmission Shop, and the Texaco Service Station, residual and dissolved hydrocarbons have been detected beneath these facilities, and a commingled plume exists beneath Charter Way and Lincoln Street It is our understanding that the groundwater flow direction near the intersection has generally been toward the east and northeast The groundwater plume has not been delineated, but reportedly, extends down gradient as far as Van Buren Street A work plan to further evaluate the extent of hydrocarbon impact, dated January 28, 2000, was submitted to San Joaquin County Department Public Health Services, Environmental Health Division (PHS/EHD) The scope of work included vertical assessment using Cone Penetrometer Test (CPT) followed by discrete soil and groundwater sampling to a total depth of approximately 120 feet below ground surface (bgs) Status retained Gregg Drilling and Testing, Inc and the work was completed on May 30, 2000 Results of the investigation were presented in a findings report dated October 27, 2000 GROUNDWATER MONITORING On August 16, 2001 a Stratus representative measured depth to groundwater and collected groundwater samples from the two onsite groundwater monitoring wells for subjective and laboratory analyses Floating product was not observed in any of the groundwater monitoring wells The locations of the monitoring wells are presented on Figure 2 Groundwater Elevation Third quarter 2001 groundwater levels were measured on August 16, 2001, using an electronic sounding device and recorded on the field data sheets presented in Appendix A Table 1 presents the historical and third quarter 2001 groundwater elevation data At the time of the third quarter 2001 monitoring event, groundwater was encountered in MW-1 and MW-2 at depths of 20 60 and 20 82 feet bgs, respectively Groundwater elevations decreased approximately 13 feet since the previous sampling event (May 17, 2001) Groundwater flow direction and gradient were not calculated, as data from only two monitoring wells is available Sampling, Analysis, and Momtoring-Program Results Groundwater samples were collected from wells MW-1 and MW-2 on August 16, 2001 Appendix B presents the sampling procedures used Samples were forwarded for analysis with appropriate chain-of-custody documentation to Alpha Analytical Laboratory, a state certified laboratory Groundwater samples were analyzed for TPHG using USEPA Method 8015B/DHS LUFT, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX), methyl tertiary butyl ether (MTBE), tertiary amyl methyl ether (TAME), tertiary butyl alcohol (TBA), di-isopropyl ether P 1I B C15tockton\Qrt1y1200NBC Stockton-3Q01 doc 5TRATUS