Laserfiche WebLink
metamorphic rocks of the Sierra Nevada and deposited in a westward-thickening wedge towards the <br /> axis of the Great Valley Province <br /> Elevation at the site is approximately 6 5 feet above mean sea level Groundwater is present in an <br /> onsite well at approximately 21 5 feet below ground surface, or approximately 15 feet below mean <br /> sea level The deeper, regional groundwater aquifer is assumed to be approximately 90 to 100 feet <br /> below ground surface at the site Shallow groundwater beneath the site is expected to have very little <br /> gradient, sloping gently in a southeasterly direction <br /> 4.0 PREVIOUS WORK <br /> Because of a suspected release of petroleum hydrocarbons to the subsurface during previous site <br /> operations, a single monitor well was installed at the site on December 5, 1990, by Roger Foott <br /> Associates, Inc of West Sacramento, California The well was developed and sampled on December <br />' 7, 1990 The groundwater sample was analyzed for total petroleum hydrocarbons as gasoline (TPHg) <br /> and for the associated volatile constituents benzene,toluene, ethylbenzene, and total xylenes (BTEX) <br /> The results of these analyses indicated that the groundwater beneath the site was impacted with <br /> petroleum hydrocarbons in the range of gasoline The laboratory detected 200 parts per million <br /> (ppm)TPHg, 31 ppm benzene, 11 ppm toluene, 1 9 ppm ethylbenzene, and 5 2 ppm total xylenes in <br /> the groundwater sample (Table 1) <br /> • <br /> I <br /> I� <br /> • <br /> SBACOR 014 01-1 par 2 <br />