ARCHIVED REPORTS XR0010058 - Laserfiche WebLink

Home Browse Search

the groundwater which occurred during lugh water levels have been extremely minimal and temporary During July 1991, BTEX and TPHg were present in well MW2 at or near the ' detection limits (0 5 to 0 6 ppb and 54 ppb, respectively) and 1n well MW3 ethylbenzene and xylenes were present at levels slightly higher than the detection limits (1 4 ppb and 0 7 ppb, respectively) During the July 1992 monitoring episode, TPHg was detected at 120 ppb and xylenes were detected at 1 8 ppb in well MW2 Based on monitoringdata from nearby facilities, regional groundwater flow in the shallow water- bearing zone beneath the Heinz plant is generally to the north Monitoring well MW2 is located approximately 35 feet north (downgradient) of the excavation Upgradient well NM is located approximately 12 feet south of the former excavation The northern property boundary, which is ' in the general downgradient direction, is approximately 1300 feet from the former tank location ' 3, .4 Remedial Actions 3.4.1 Soil Remediation On September 14, and 17 through 21, 1990, the former tank pit area was over-excavated Approximately 800 cubic yards of soil were removed from the excavation (RESNA 1993) The final excavation limits were approximately 55 feet by 35 feet The vertical extent of excavation was approximately 9 5 feet deep, the depth at which groundwater was encountered Evidence of hydrocarbon odors and soil discoloration was noted from 6 feet to 9 5 feet bgs (RESNA/WaterWork 1990) All observable contaminated soil was removed 1n the northern, eastern, and western directions High voltage lines and a light pole prevented complete ' excavation of all contaminated soils above the water table along the southern boundaries of the excavation The total volume of impacted soil which was left in place following excavation, due ' to physical constraints, is estimated to be 67 cubic yards (Table 5) It is estimated that the excavation of soil removed 92% of the total volume of petroleum contaminated soil at the site ' (Table 5) On September 21, 1990, seven confirmation soil samples were collected at the bottom of the excavation along the side walls (Figure 2) Petroleum hydrocarbons as diesel were not present in the soil samples collected from the north wall, low levels were present in the soil samples collected from the east and west walls The sample collected from the south wall of the w 1967311reportslClosure doc 4 • 1 Sian