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Mr. Vidal Pedroza '" I March 23, 2000 Page 3 of 6 collect soil samples at the approximate depth of the bottom of the USTs and at approximately four feet below the tank bottom. However, due to the presence of underground utilities just south of the USTs, only three of the borings'(SB L SB2, SB3) were advanced as angle borings. Borings SB4, SBS, and SB6 were located approximately 4 feet south of the USTs and were advanced vertically to a depth of approximately 15.5„feet bgs, except for boring SB4, which was advanced to approximately 20.5 feet bgs. Due to surface light pole that hindered positioning of the drilling rig, the surface starting point for boring SB2 was located at an oblique angle from the long axis of the tank. The boring was advanced at a 30 degree angle to collect soil samples as previously described. A groundwater sample was collectedfrom boring SB 1 by installing a temporary well screen in the boring, inserting a 0.17 diameter PTFE tube equipped with a stainless steel check valve into the well screen, and extracting groundwater from the boring by creating a positive displacement effect within the tubing, forcing the water sample towards the surface where it was collected directly into sample containers. Borings SB7 through SB14 were advanced along the product pipeline to depths ranging from 3.5 feet bgs to 6 feet bgs. Every attempt was made to advance the soil borings along the product pipeline at 20 foot intervals. However, distances between several borings exceeded 20 feet due to certain site features which hindered access, such as a water fountain and other ornamental displays, and underground utilities. Mr. Pedraza of PHS/EHD was consulted on and approved all boring locations. Soil boring locations are presented on Figure 1. A cross section of the UST area is shown on Figure 2. The completed borings were backfilled via tremmie piping to the ground surface with neat cement grout. No soil cuttings were generated. All down-hole drilling and sampling equipment was decontaminated by washing with a laboratory grade detergent and rinsing with water. Rinseate collected from decontamination procedures was disposed of by Fisch. Soil and groundwater samples were submitted under chain of custody procedures to Argon Laboratories for analysis. 4.0 RESULTS OF INVESTIGATION 4.1 Subsurface Conditions Soil samples collected at a depth of approximately I1 feet bgs in the vicinity of the USTs consisted of lean to silty clay. Soil "samples collected at depths of approximately 14.5 and 19.5 feet bgs were generally sandy silt. Evidence of groundwater was encountered in borings SBI and SB2 at approximately 14 feet bgs, and at approximately 10 feet bgs in boring SB6. However, only ;1 boring SB 1 (North side of Tank 1)yielded enough water to collect a groundwater sample. Slight petroleum hydrocarbon odors were noted in the soil samples collected from boring SB4 at approximately 11 feet bgs and 14.5 bgs. Gray,discoloration was apparent in the sample collected from 14.5 feet bgs. Field meter readings(FID readings)ranged from 1 part per million (ppm)at 11 G:1Data%GROUNDZE1Watediont\Subswfstan.doc 3 I