Laserfiche WebLink
F <br /> OEM Mal <br /> ELININ RY YD OGBOLOGIC AS5ESSMENT P.EPORT <br /> 1399 East yoeemite Avenue,Mentees,California <br /> Delta Project No.60-88-480 <br /> Page 12 <br /> May 1988). As shown in Figure 4, concentrations Of these low levels of petroleum hydrocarbon <br /> constituents in soil appezrs to be isolated in the soils approximately 20 feet below grade around borings <br /> MW-1 and MW-3. <br /> q,Z patent or Dissolved 11 fdrocarbon Constituents in Ground Water <br /> Small amounts of hydrocarbon constituents were detected in monitoring wells MW-2 and MW-3. MW- <br /> values of benzene than the state action level <br /> ontained slightly higher o p (Table <br /> w 5.0 RFCGMMF•NDA T IONS <br /> 4.It is recommended that future work be limited to the collection and analysis of quarterly water samples <br /> and bimont:ily water level data from the monitoring wells at the site for the period of 1 year. Water <br /> od 524.2. Results of water analyses and.eater <br /> samples will be analyzed for BTEX and TPH by EPA Meth <br /> level data will be presented in a Quarterly Monitoring Report. At the end of 1 year,or at any time that <br /> results of quarterly sampling indicate that ground water quality at the site has been affected,the need for <br /> future assessment at the site will be re-evaluated. Quarterly monitoring is adequate for the site for the <br /> following reasons: <br /> o Low levels of petroleum hydrocarbon constituents in the soils surrounding tanks. <br /> H . Low levels of petroleum hydrocarbon constituents in ground water samples. <br /> Tanks and lines have tested tight. <br /> v The site is covered by a 2-inch-thick layer of asphalt which will prevent direct infiltration of <br /> precipitation to the soils at the site, thereby preventing the leaching of any petroleum <br /> constituents in the soils to ground water. <br /> ` 6.0 115E7'I1OD5 AND PROCEDURES <br /> 6.1 Drillinand Soll Sam lir, <br /> Two soil borings were drilled at the site on April 27, 1989. Soil borings were drilled using a mobile B- <br /> 53 drilling rig and 6-3/4-inch-Outside-diameter hollow-stem.-augers. The sort borings were drilled to a -- ------- -_--_--------- <br /> �- maximum depth of 36 feet below grade. <br />