Laserfiche WebLink
MV o <br /> A S S O C I A T E S I N C <br /> hydrocarbons as stoddard solvents (TPHss). The September 1998 subsurface investigation <br /> results are detailed in ATC's Summary Report of Soil Excavation and Additional Subsurface <br /> Investigation, dated December 3, 1998. <br /> On March 23, 2000, an ATC geologist supervised the advancement of one angle soil boring, S132A, <br /> to approximately 32 feet bgs. The boring was advanced at a thirty-degree angle from the vertical, <br /> directly under the on-site building, south of the former UST location. Soil samples and a grab <br /> ' groundwater sample were collected. The soil and groundwater samples contained no detectable <br /> concentrations of TPHg, TPHd, TPHss, benzene, toluene, ethylbenzene, and xylenes (BTEX), or <br /> oxygenate fuel additives. <br /> ' On April 9, 2000, an ATC geologist supervised the installation of one groundwater monitoring <br /> well to approximately 39 feet bgs. Soil samples were collected at five-foot intervals. The well <br /> was developed and groundwater samples were collected. The soil and groundwater samples <br /> contained no detectable concentrations of TPHg, TPHd, TPHss, BTEX, or oxygenate fuel <br /> additives. The March and April 2000 subsurface investigation results are detailed in ATC's <br /> Summary Report ofAdditional Subsurface Investigation, dated May 16, 2000. <br /> 3.5 Soil and Purgewater Disposal <br /> Soil cuttings generated during subsurface investigation activities were disposed of in September <br /> 1998 by Bob Evans Trucking at the Forward Inc. Landfill in Stockton, California. Soil cuttings <br /> ' generated during the installation of well MW4 were transported and disposed of in September <br /> 2000 by ATC at the Forward Landfill in Stockton, California. Purged groundwater generated <br /> during monitoring activities is regularly transported and disposed of by Norcal Oil. Currently <br /> there are approximately 100 gallons of monitoring well purge water stored on site. This purge <br /> water will be transported and disposed of after the site has been granted NFA. �Q <br /> ' A summary of analytical results for soil is presented in Table 1, historical analytical results for <br /> groundwater are presented in Table 2, and historical groundwater monitoring data are presented in <br /> tTable 3. <br /> 4.0 EXISTING CONDITIONS <br /> ' 4.1 Soil Conditions <br /> ' 4.1.1 Site Geology <br /> Native sediments encountered in soil boring SBI during field activities indicate that the upper 6 <br /> ' feet of the soil column consists primarily of organic soil that was used as backfill material. <br /> Soils from between approximately 6.5 to 10 feet bgs and 21.5 to 25 feet bgs consist of silt and <br /> elastic silt. Soils from between 21.5 to 25 feet bgs and 31.5 to 35 feet bgs consist of lean clay. <br /> Soils from between 31.5 to 35 feet bgs and 36.5 to 40 feet bgs consist of elastic silt. Soils <br /> w,\I72951reportsklosure.doc 3 <br />