ARCHIVED REPORTS XR0000841 - Laserfiche WebLink

Home Browse Search

28 August 2000 AGE-NC Project No. 98-0481 Page 2of8 2.2. UNDERGROUND STORAGE TANK REMOVAL In July 1997, Walton Environmental, Inc. excavated and removed the three fuel USTs, the waste oil UST, the fuel dispenser island and associated product piping. As part of the removal activities, Grayland Environmental collected a total of eleven soil samples for laboratory analysis beneath the I USTs,pump island, and associated product piping. Approximate soil sample locations are illustrated on Figure 2. Soil samples were collected at approximately 12 to 14 feet bsg in the UST area; approximately 4 feet bsg in the fuel dispenser island and product piping areas; and approximately 8 feet bsg in the waste oil UST area. Soil samples were analyzed for BTEX, TPH-d, TPH-g, methyl tertiary-butyl ether(MTBE), and total lead. I BTEX, TPH-d, TPH-g, MTBE or total lead were not detected in the six soil samples collected beneath the three fuel USTs or product piping located between the tank excavation and the fuel dispenser island. However, BTEX, TPH-d, TPH-g, and MTBE compounds were detected in three I soil samples collected beneath the fuel dispenser island and product piping located along the southern side of the fuel dispenser island. The highest concentrations of target compounds were detected in soil samples collected beneath the fuel dispenser island. BTEX compounds were detected at concentrations as high as 0.14 parts per million (ppm) benzene, 0.75 ppm toluene, 0.021 ppm ehtylbenzene and 0.73 ppm xylenes. TPH-d and TPH-g were detected at 140 and 1.9 ppm, respectively. In addition, benzene, TPH-d, and MTBE were detected in the soil sample collected r beneath the waste oil UST. Total lead was not detected at concentrations greater than 10 ppm in any 1 of the soil samples analyzed (Table 1). During the tank removals, excavated soil was stockpiled at the site. A total of five composite soil samples were collected from the stockpiles for laboratory analysis. TPH-d was detected in one composite stockpile sample; BTEX, MTBE, and TPH-g were detected in two composite stockpile samples. Elevated concentrations of total oil and grease, halogenated volatile organic compounds (HVOCs) and LUFT metals were detected in the composite sample collected from the waste oil UST stockpile. 2.3. PREVIOUS SITE INVESTIGATIONS In May 1993,WHF Environmental,Inc. conducted a Phase II Site Assessment to evaluate subsurface soil for possible petroleum hydrocarbon contamination resulting from historical hydrocarbon fuel storage and distribution operations at the site. During the Phase II investigation, four soil borings (B-1 through B-4) were advanced in the vicinity of the three former fuel USTs and the former dispenser island. Approximate boring locations are illustrated on Figure 2) Soil samples were collected from each of the borings at depths of 15, 20, and 25 feet below surface grade (bsg) and were submitted for Iaboratory analysis. Advanced GeoEnvironmentai,Inc.