Laserfiche WebLink
March 18, 1993 <br /> Page 3 <br /> Historical groundwater elevations are presented in Table 1. Soil analytical data <br /> originating from the above investigations is presented in Table 2. Historical <br /> groundwater analytical data is presented in Table 3. <br /> Relevant Findings <br /> Key site characteristics relevant to interim remedial action are outlined below: <br /> o Groundwater ChemistGroundwater flow direction has been <br /> t the site with a gradient ranging <br /> . from 0. 3 t � nca�:a <br /> o Soil Chemistry: The highest hydrocarbon concentrations in the <br /> soils were found west and adjacent the aboveground storage <br /> tanks, and lower concentrations to the south, with no detectable <br /> concentrations occurring in the soils that were examined.off site. <br /> In general, hydrocarbon concentrations in the soil attenuate with <br /> depth and appear to be localized near the coarse-grained <br /> sediments underlying the aboveground storage tanks. The <br /> horizontal extent of petroleum hydrocarbons in the soil has been <br /> defined to nondetectable levels to the east and west, to below <br /> 100 parts per million(ppm) to the north, and below 500 ppm to <br /> the south. These high-permeability sediments may be providing <br /> route for hydrocarbon migration. 0Wb�ns d eft C MdM <br /> � r domi7 ti M A;0II& i l' <br /> Thus; appears that most of the hydrocarbon mass is above the <br /> piezometric surface. Hydrocarbon concentrations generally <br /> attenuate to levels below 50 ppm at depths greater than 10 feet <br /> west and east of the site. <br /> o Regulatory: The immediate contact at the Central Valley <br /> Regional Water Quality Control Board (CRWQCB) is <br /> Mr.James B. Maughan. At the local level, the San Joaquin <br /> County Public Health Services Environmental Health Division is <br /> involved; Ms. Mary Meays is the contact. Anticipating the possi- <br /> bility of using groundwater extraction and treatment as a facet of <br /> interim remediation, the City of'Tracy was contacted. This <br /> contact was made to explore the feasibility of using the sanitary <br /> sewer system as a point of treated groundwater discharge. <br /> 3100104/IRAP <br />