SITE INFORMATION AND CORRESPONDENCE

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x In January 1990, a single borehole was installed .in the center of the former Tank T2 area. This borehole extended to the first groundwater with soil samples being collected every 5 feet. Included with. the soil samples, a single water sample was coll"ected through the annulus of the hollow stem auger'. Of the seven soil samples and the one groundwater sample collected in January 1990, two soil samples exhibited traces of TPH as diesel at concentrations of 18 mg/Kg and 17 mg/Kg. In addition to . the TPH-D concentrations detected, very . minor traces of toluene and . xylene were detected. I On March 26, 1990, ROY F. WESTON, INC. .(WESTON) installed a single groundwater monitoring well. The purpose of installing ,this well was to gain access to groundwater beneath the former underground storage tank- location T- 2 . The well was located five feet northwest of ajsoil boring which was drilled, logged and sampled on January 24 , 1990. Due to the well 's close proximity to the soil boring, no soil samples were . collected and no lithologic log was made of the boring. Observation of cuttings returned to the surface during 4 the well installation indicated, lithologi.cally, that subsurface stratigraphy in the well was virtually identical to that encountered in the soil boring. The well was drilled using a CME-55 drilling rig with a 9 1/4 inch diameter hollow stem auger. The boring was advanced to approximately 50 feet below ground surface (BGS) and the hole tested for the presence of groundwater. The depth to water was measured using an electronic r sound ing. device and found C to be . 48.9 feet BGS. The boring was then advanced to a total depth of 59 feet. After the center rods were removed, the- total depth was measured again and found to be 58 . 5 feet, a loss of one half foot due ;to heaving sands. When the PVC screen and casing was installed, the sand had lowered back to 59 feet. f t Two groundwater samples were collected from the monitoring well. The initial sample was collected on April '2, 1990 with the confirmation sample collected on May 2 , 1990. The collected samples were analyzed for ,TPH utilizing EPA Method 8015 and for BTX&E utilizing EPA Method 602 . For both sampling periods, the depth to water in the monitoring well was 3 measured and the total well depth was verified prior to ,the collection of the water .sample. Using these measurements, the volume of the standing water in the well and the required purge volume were calculated and recorded on a standardized well sampling log sheet. Prior to purging of the well, a sample of the standing water was collected with a teflon bailer lowered :;on monofilament line. This water sample was stored with ice in an insulated chest pending transport .to the laboratory and submission for analysis for TPH-D. by EPA Method 8015E. The well was then purged, again using a teflon bailer .lowered into and retrieved from the well using new, clean monofilament `line. At the beginning of the well purge, the Ph, temperature, and specific conductivity of the water was measured and recorded. These measurements were again taken at the end of the purge,. The purge removed three standing well casing volumes. 3 _ y