ARCHIVED REPORTS XR0000745 - Laserfiche WebLink

Home Browse Search

10 September 1996 AGE-NC Project No. 95-0106 Page 4 of 8 3.2. MONITORING WELL INSTALLATION 3.2.1. DRILLING AND SOIL SAMPLING On 01 and 02 July 1996, soil borings MWA through MW-4 were drilled and completed as ground water monitoring wells. Boring MW-I was established in the driveway on site; boring MW-2 was advanced south of both the former UST excavation and the garage structure; boring MW-3 was established in the City of Tracy sidewalk on the south side of Beverly Place, east of the site; and boring MW-4 advanced in the northern parking lane of Beverly Place. The installation of MW-1 through MW-3 was performed using a truck-mounted CME 75-HT drill rig equipped with continuous flight, eight-inch, hollow-stem augers. The installation of MW-4 was performed using a limited access drill rig with continuous flight, eight-inch, hollow-stem augers. Both drill rigs and two-man crews were supplied by Soils Exploration Services (SES) of Benicia, California. The locations of the borings are shown on Figure 2. Samples were collected in each boring using a split tube sampler loaded with three clean, 2- by 6- inch brass sleeves. A 140-pound hammer was used to advance the sampler 18 inches; the number of blows required to advance the sampler in 6-inch increments was recorded on the boring logs. All sampling equipment was washed in an Alconox solution and rinsed twice with water prior to each sampling run. Both ends of the leading sleeve of each sample collected for laboratory analysis were covered with Teflon sheets, capped and sealed with tape. The samples were stored in a chilled container and transported under chain-of-custody to McCampbell Analytical, Inc. (MAI) in Pacheco, California. Selected samples were analyzed for total petroleum hydrocarbons quantified as gasoline (TPH-g), volatile aromatics (benzene, toluene, ethyl benzene and xylenes: BTE&X) and methyl-tert-butyl ether(MTBE) in accordance with EPA methods 5030/8015m, 8020 and 8020, respectively. During drilling, auger returns were monitored for the presence of organic vapors using a photo- ionization detector(PID: Thermo Environmental 580A, 10.0 eV, calibrated to isobutylene). Auger returns were then placed on plastic sheeting and stored on-site pending laboratory analysis and disposal at a licenced facility. 3.2.2. LOGGING Soil was extruded from the second brass sleeve and screened for the presence of organic vapor,using . a PID. The PID readings were recorded on the boring logs. The soil was then described in