Laserfiche WebLink
16 AddRwnaf Site Assessment Report and Work Plan for Adddional Subsurface Investigation 4 <br /> The Southland Corporation,Store 919976,1399 N Main St,Manteca,California June 5,1998 <br />' 4 3 Results of Groundwater Sample Analyses <br /> Table 2 summarizes the laboratory analytical results of groundwater samples collected from three sod <br /> borings GP-1,GP-2,and GP-3 on April 29, 1998 Benzene and TPH-G ranged from 21 micrograms per <br /> liter(pg/L) and 1,600 pg/L,respectively in sample GP-2-W,to 5,800 pg/L and 290,000 pg/L, respectively in <br /> sample GP-3-W MTBE was detected in samples GP-1-W,GP-2-W, and GP-3-W at concentrations of 430 <br />' pg/L, 16 pg/L,and 4,200 pg/L,respectively MTBE was confirmed in sample GP-1 W and GP-3-W at a <br /> concentration of 380 pg/L and 3,700 pg/L, respectively, using EPA method 8260 Copies of laboratory <br /> analyses reports and chain-of-custody are included in Appendix C <br /> 5.0 PROPOSED FURTHER INVESTIGATION <br /> The purpose of further work at the site will be to verify the extent and concentrations of hydrocarbons at this <br /> site, and collect information substantiating either 1) no further action, 2)closure after site-specific risk <br />' analysis, or 3)the need for active cleanup measures r <br /> 51 Drilling and Soil Sampling <br />' Fluor Daniel GTI will drill three sod bonngs at the locations shown on figure 2 using a truck-mounted drill ng <br /> equipped with 8-inch-diameter hollow-stem augers The bonngs will be drilled to approximately 30 feet <br /> below ground surface(BGS),and will be used to characterize and delineate the extent of the sod <br /> hydrocarbon plume Permits for the dnl ling will be obtained from the SJCPHS <br />' Sod samples will be collected from each sod boring at 5-foot intervals to a total depth of 30 feet BGS <br /> beginning at 5 feet BGS using a spill-spoon sampler lined with 2-inch-diameter by 6-4nch-long brass sample <br /> tubes If field observations indicate the sod samples collected at 30 feet BGS contain elevated <br />' concentrations of petroleum hydrocarbons,the boringswill be extended to 35 feet BGS The hollow-stem <br /> auger;will be steam cleaned before drilling, and sampling equipment will be cleaned between each <br /> sampling interval Each soil sample will be screened for hydrocarbon vapors using a photo ionization <br />' detector(PID) Soils encountered during drilling will be logged using the Unified Soil Classification System <br /> by a Fluor Daniel GTI field geologist,working under the supervision of a California registered geologist <br /> One undisturbed sample tube from each sampling Interval will be sealed with Teflon sheets, capped,taped, <br /> labeled, and placed on ice in an Insulated container for transport to the laboratory under legal chain-of- <br /> custody <br />' Based on field observations,selected soil samples from each borehole will be analyzed by a state-certified <br /> analytical laboratory for benzene,toluene, ethylbenzene and xylenes(BTS, methyl tert-butyl-ether <br />' (MTBE), and total petroleum hydrocarbons-as-gasoline(TPH-G) by EPA methods 8020/8015 modified An <br /> estimated three soil samples from each bonng will be analyzed <br /> 19976mr rpt <br />' FLUOR DANIEL GTI <br /> 1 <br />