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� `� llflMlGX-a�IEB►YfB Mr. Charles Leubner 9 July 1997 Page 3 Gasoline Tank(Tank No 2) As part of the removal activities for the 500-gallon underground gasoline fuel storage tank, one soil sample was collected from the tank excavation at the location shown on Figure 3. The results of that sampling are shown on Table 1. Total petroleum hydrocarbons as gasoline (TPH-G) was detected at a concentration of 290 mg/Kg and benzene, toluene, ethylbenzene, and xylenes were detected at concentrations of 75 ug/Kg, 2,500 ug/Kg, 1,900 ug/Kg, and 20,000 ug/Kg, respectively. Ethylene dibromide was detected at 4.1 ug/Kg. We will attempt to drive one deeper boring (B-6) over the former tank site; but, because of the pea gravel used as backfill for the excavation, we may have to bore the deep boring next to the tank site. Three additional soil borings are proposed to evaluate the lateral extent of petroleum hydrocarbons remaining in the soil (see Figure 3). All four soil borings will be driven to a depth of 25 feet below the ground surface. At a minimum, two soil samples will be collected for laboratory analysis from each soil boring- one from the 25- foot depth and one that is the likeliest of the remaining samples to contain the highest concentration of hydrocarbons based on field observations such as staining, odors or the presence of elevated organic vapors. if indications of petroleum hydrocarbons are noted at other depths, additional samples may also be analyzed to better evaluate the extent of hydrocarbons in the soil. FIELD INVESTIGATION PROTOCOL Soil samples will be collected using a hydraulically driven, 1-inch diameter continuous corer. Soil samples will be collected at a minimum of 5-foot intervals for lithologic logging, field screening, and possible laboratory analyses by inserting PETG liners inside of the corer. To minimize the potential for cross-contamination, coring equipment and liners will be cleaned with a high-pressure hot water washer prior to drilling each boring. After the soil samples are collected, the soil borings will be backfilled with a neat cement grout using a tremmie pipe. The section of the liner containing the soil sample to be submitted to the laboratory for analysis will be sealed with aluminum foil or Teflon sheets secured by plastic caps. The liner will then be labeled to indicate a unique sample number, the date and time collected, and the sampler's identification. The samples will be stored in an ice-chilled cooler for preservation during transport to a State- certified laboratory for analysis. Soil samples will also be logged using the Unified Soil Classification System and selected samples will be screened in the field for the presence of organic vapors. Rinse water will be stored in drums at the site for subsequent disposal.