ARCHIVED REPORTS XR0010527 - Laserfiche WebLink

Home Browse Search

• 4.3 Laboratory Results Table 1 summarizes the analytical results of the soil samples Gasoline (TPH-g) was detected in four of the analyzed samples from JLM-2, at concentrations that range from 32 milligrams per kilogram (mg/kg = parts per million) to 1300 mg/kg Ethylbenzene and xylene were also detected in these samples, but benzene and toluene were not detected above (elevated) reporting limits No gasoline oxygenates, EDB, or 1,2-DCA were detected in any of these samples, and no hydrocarbons of any type were detected in samples at 30 and 35 feet in JLM-2 or in the two samples (25 and 30 feet) in JLM-1 One sample (JLM-2-15') was analyzed for TPH-d, and four samples were analyzed for total lead Neither diesel not lead were detected in aqy of the samples Hydrocarbons were present in both water samples (Table 2) Gasoline was present at a concentration of 460 micrograms per liter (µg/l, =parts per billion) in JLM-1 and at 2300 µg/l in JLM-2, and most BTEX compounds were detected as well, as were MTBE and 1,2-DCA The sample from JLM-2 was not analyzed for diesel, but diesel was detected in JLM-1 at 610 pg/l Because most analytes (except MTBE and 1,2-DCA) were detected at higher concentrations in JLM-2 than in JLM-1, it is probable that diesel would have been detected in JLM-2 too 5.0 DISCUSSION AND CONCLUSIONS Although only two borings were drilled in this investigation, several conclusions g us ons can be drawn from the data That were collected 1) Boring JLM-1, which was drilled in the vicinity of the dispenser islands where soil contamination was originally discovered, found no evidence of residual soil contamination This aids further support to the conclusion in the 1995 Site Remediation Report that all contaminated soil in the main area of the petroleum leak was removed during the site e-<cavation woik No contaminated soil was evident below a depth of 25 feet in the original excavation, and soil samples collected at 30 and 35 feet from JLM-1 were not contaminated 2) Boring JLM-2 confirmed that the soil near the front of the station building is contaminated at shallow depths, but is not contaminated at 30 or 35 feet Hydrocarbons are present at least as shallow as 10 feet, and probably shallower Such shallow contamination could not have originated from one of the underground tanks, which were buried deeper than this and appear to have not leaked This contamination could also not be due to lateral spreading from the dispenser leak at sample point JP-3 (Figure 2), because it would regvire the gasoline to have migrated horizontally within the unsaturated zone, which is physically pioblernatic Therefore. the most likely reason for the presence of gasoline in the sail ai a depth of 5 or 10 feet in JLM-2 is a previously unidentified pioduct-line leaf near the building Whether product lines were formerly . located in this vicinity is presently uncertain 5