WORK PLANS - Laserfiche WebLink

Home Browse Search

v A S S O C I A T E S I N C soil sample was collected from each end of the 12,000-gallon and the 10,000-gallon USTs. Analytical testing indicated the samples collected from beneath the 10,000-gallon and 750-gallon gasoline USTs contained detectable concentrations of petroleum hydrocarbon constituents. The excavations were subsequently backfilled. In October 1997, an ATC geologist supervised the advancement of one soil boring to 31 feet bgs, one soil boring to 26 feet bgs, and five soil borings to 20 feet bgs. Soil borings SB 1 through S136 were placed in the vicinity of the former 10,000-gallon UST and soil boring S137 was placed in the vicinity of the former 750-gallon UST. A site plan with soil boring locations is shown on Figure 2. The borings were advanced using a truck mounted Geoprobe® narrow diameter rig employing direct push technology. Soil and grab groundwater samples collected from the vicinity of the former 10,000-gallon UST contained elevated concentrations of petroleum hydrocarbons. Field activities were summarized in ATC's Summary Report of Subsurface Investigation, dated November 24, 1997. In August 1998, ATC personnel supervised the advancement of three soil borings at the site. Drilling was performed using hollow stem auger. In accordance with the approved workplan, the soil borings were completed as groundwater monitoring wells MW1, MW2, and MW3. Soil samples contained detectable concentrations of petroleum hydrocarbons. The groundwater monitoring wells were subsequently developed and the groundwater samples contained detectable concentrations of total petroleum hydrocarbons as diesel (TPHd). Field activities were summarized in ATC's Summary Report of Additional Subsurface Investigation, dated October 19, 1998, In April 2000, an ATC geologist supervised the advancement of two soil borings to 21 feet bgs and one soil boring to 31 feet bgs. A site plan with soil boring locations is shown on Figure 2. The borings were advanced using a truck mounted Geoprobe® narrow diameter rig employing direct push technology. Soil and grab groundwater samples collected from the soil borings contained no detectable concentrations of petroleum hydrocarbons. SCOPE OF WORK Well Installation To evaluate the vertical extent of soil and groundwater contamination at the site, two soil borings will be advanced off-site to a depth of approximately 28 feet below ground surface (bgs) utilizing a hollow stem auger equipped drill rig. The proposed monitoring well locations are shown on Figure 2. Drilling will be conducted by a State-licensed (C57) drilling company. A field geologist will be present to log drill cuttings and soil samples. Descriptions of soil types encountered and sample collection intervals will be recorded on the boring logs. Soil samples will be collected at five- w:1625001reportslwkpiiiadd.doc 2