Laserfiche WebLink
cWtogial ravars rfv- Page 12 <br /> Valley Wholesale Drug Company <br /> Project No 989 2 <br /> November 8,2004 <br /> • GTI Site Characterization, Monitoring well Installation and 3rd Quarter 2002 <br /> Groundwater Monitoring Report—October 31, 2002 <br /> ' • GTI Site Conceptual Model Report—December 17, 2003 <br /> 3.11 Background Conditions <br /> A water quality degradation analysis is summarized below in accordance with § 2550 4(d) of <br /> Title 23, California Code of Regulations, Chapter 15 <br /> ' 1) Potential adverse effects on groundwater quality and beneficial uses <br /> A The constituents of concern and average concentrations at the VWDC site <br /> include <br /> ' o TPH-gasohne -- assuming all non-detect wells have a concentration of 20 <br /> µg/L there is an average concentration of 0 1 mg/L <br /> o Benzene —assuming all non-detect wells have a concentration of 0 2 µg/L <br /> ' there is an average concentration of 0 83 µg/L(below MCL) <br /> o Toluene — assuming all non-detect wells have a concentration of 0 2 µg/L <br /> there is an average concentration of 0 25 µg/L(below MCL) <br /> o Ethyl benzene— assuming all non-detect wells have a concentration of 0 2 <br /> 4g/L there is an average concentration of 2 24 lig/L(below MCL) <br /> o Total Xylene — assuming all non-detect wells have a concentration of 0 2 <br /> µg/L there is an average concentration of 125 �g/L(below MCL) <br /> o MtBE — assuming all non-detect wells have a concentration of 0 5 [Lg/L <br /> ' there is an average concentration of 16 25 µg/I. <br /> B Hydrogeological characteristics of the facility and surrounding land are <br /> relatively uniform layers of clay-silt mixtures, sand-clay mixtures and clays <br /> ' The details are discussed in Section 2 5 <br /> C Groundwater bearing and slope average N30°W at 0 0065 ft/ft as discussed in <br /> Subsection 2 5 3 2 Groundwater velocity is estimated to be 0 012 to 0 020 <br /> ' feet per year as discussed in Subsection 2 5 3 3 <br /> D There are no groundwater users within a 20W-foot radius of the VWDC site <br /> as discussed in Section 3 1 <br /> ' E According to the USDA Soil Survey of San Joaquin County, California <br /> (McElhiney, M A , 1992), streets, parking lots,buildings, and other structures <br /> cover more than 85 percent of the surface of the soils on or near VWDC The <br /> ' details are discussed in Subsection 2 5 2 It is not likely that potential future <br /> uses of groundwater in the area will be impacted <br /> ' F Background wells show similar pH, EC, ORP, DO and temperature readings <br /> to those recorded in contaminated wells There were no potential sources of <br /> contamination detected within 2000 feet of VWDC The source of <br /> contamination has been removed and it is likely the site will return to <br /> background conditions via natural attenuation <br /> G According to the USDA Soil Survey of San Joaquin County, California <br /> (McElhmey, M A , 1992), the urban land unit underlying VWDC consists of <br /> 1 <br />