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1 <br /> Geofagual?ecFvzus Inc Page 2 <br /> Additional Site Charactenzation <br /> Morita Brothers <br /> Project No 724 2 <br /> December 19,2000 <br /> well bonngs, MW-6, MW-7 and MW-104, the wells were free drilled to depths of 45, 45 <br /> and 55 feet bgs, respectively Soil samples were then collected from these depths to the <br /> borings' terminus A boring log, providing a description of the sediments encountered <br />' during this investigation, using field observations and the USCS, was maintained by a <br /> professional geologist working under the supervision of a registered geologist Soil samples <br /> were collected in 6 0-inch brass liners using a 2 0-inch modified California split spoon <br /> sampler The soil samples were sealed with Teflon sheets, capped with plastic end caps, <br /> labeled, and placed in a cooler at 4° Celsius for transport to the laboratory following Chain <br /> of Custody protocol An OVM was used to screen the soil samples <br /> Details on the geology encountered during the completion of the soil sampling as well as the <br /> field observations are included in Section 3 2, Geology and Field Observations <br /> 2.1.2 Soil Laboratory Analyses <br /> Select soil samples from each borehole were submitted to Sherwood Laboratories of Hilmar, <br /> California (State Certified Laboratory #1400) for the following analysis <br />' • Benzene, toluene, ethylbenzene and xylene (BTEX) by EPA method 8020 <br /> • Gasoline-range petroleum hydrocarbons (TPH-G) by EPA method 8015(m) <br /> • Methyl tertiary butyl ether (MTBE) by EPA method 8020 (with confirmation by EPA <br /> Method 8260) <br /> A chain of custody was completed for all samples submitted and tracked to ensure sample <br /> integrity <br />' 2.2 Monitoring Well Installation <br /> To investigate the lateral and vertical extent of gasoline-range petroleum hydrocarbons in <br /> the groundwater at this site, Geological Technics Inc installed two monitoring well pairs- <br /> MW-6 and MW-106, MW-7 and MW-107 (Figure 2, Site Map) Wells MW-6 and MW-106 <br /> were placed on the adjacent parcel to the east of the site, approximately 60 feet south of <br /> MW-5 Wells MW-7 and MW-107 were placed approximately 15 feet east of the former <br /> UST field The locations of both of these well sets were adjusted as necessary to remain <br /> clear of overhead utilities <br /> A discretely screened deep well, MW-104, was placed adjacent to the former dispenser <br /> island on the western portion of the site <br /> The monitoring wells were constructed using 2-inch diameter PVC casing with flush <br /> threads The table below shows the construction details The filter packs were surged <br /> during placement to insure maximum filter pack density <br /> We ia. Screen Slot Sand PackTrans Seal Grout Seal <br /> No. (in/ft) (ft) (ft) (ft) (ft) (ft) <br /> sari - - <br /> sand - - 0-205 <br /> 211/90 97 5-90 sari - 0-83 <br /> - sari - - 0-51 <br /> sari - - <br />