ARCHIVED REPORTS_XR0011615 - Laserfiche WebLink

Home Browse Search

i Kennedy,Jenks Consultants 1.2 Regional Groundwater Quality Based on regional information, it appears that shallow groundwater is present at approximately 50 feet below groundsurface (bgs) in the vicinity of the Site, and that the ' gradient direction is north to northeast According to the Agency, VOCs attributed to dry cleaning operations have been observed in the Stockton sanitary sewer system In the vicinity of the Site, the direction of flow in the sanitary sewer system along East Market Street is from east to west (Sasson 1996) As identified in the Phase I ESA, Valley Motors located at 800 East Main Street, approximately 0 08 miles northeast of the Site documented the presence of total petroleum hydrocarbons as gasoline (TPHg) and diesel (TPHd), benzene, toluene, ethylbenzene, and xylenes (BTEX), and volatile organic compounds (VOCs) in groundwater samples in the vicinity of the property Although Valley Motors appears to be crossgradient of the Site, the groundwater gradient may not be fully understood, and there is the potential that chemicals, VOCs in particular, have migrated laterally through conduits such as the sewer system 13 Objectives and Scope of Work ' The purpose of the shallow soils investigation was to evaluate if soils in the immediate vicinity of the four areas identified in Section 1 1 have been impacted by chemicals of concern In addition to the soils, the first-encountered groundwater(shallow groundwater) quality was also investigated to determine if shallow groundwater has been impacted by chemicals ' of concern from potential onsite sources Based on regional information, it was assumed for the purpose of boring placement that shallow groundwater is present at approximately 50 feet below groundsurface (bgs) in the vicinity of the Site, and that the gradient direction is northeast To accomplish these objectives, Kennedy/Jenks performed the following investigation activities 0 Obtained permits • Conducted a geophysical survey to assess the presence and configuration of potential USTs, and associated piping and sumps, that were identified in the Phase I ESA • Advanced Soil Borings SB-1 through SB-7, and Soil Boring SB-11 to collect subsurface sod samples for field screening and laboratory analyses ' . Advanced Soil Bonngs SB-8 through SB-10 to collect reconnaissance groundwater samples to assess potential chemical impacts to shallow groundwater at the Site from potential onsite sources The field investigation, analytical results, conclusions, and recommendations are summarized in subsequent sections of this report I yob%%'Q 6070 Wphase ultextdoc 2