ARCHIVED REPORTS XR0001000 - Laserfiche WebLink

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• Purging the wells are summarized on TABLE XI; lab reports and chain of custody are included as EXHIBIT J MW -1 showed minor amounts of toluene (4 0 ug/L,) xylene (0.4 ug/L,) & TPH-G (78 0 ug/l ) Benzene, Ethylbenzene & TRPH were below detection limits MW -2 measured toluene at 0 4 ug/L, and xylene at 0 5 ug/L, benzene, ethylbenzene, TPH-G, and TRPH were below detection limits MW -3 recorded benzene at 0.6 ug/L, all others were below detection limits MW -4 recorded benzene at 0 5 ug/L, toluene at 0 5 ug/L, xylenes at 12 0 ug/L, and TRPH (diesel range organics,) at 6900 mg/kg Ethylbenzene and TPH-G were below detection limits Two cross-sections were constructed through some of the auger holes and monitoring wells to show details of the lithology encountered, their locations are shown on PLATE XXI Cross- section A -B, (PLATE XIX,) goes through MW -2, auger hole "B" MW -3, auger hole "D", and MW -4 Auger hole "C" is projected into the line of section Cross-section C -D, (PLATE XX,) goes from MW -3, through auger hole "A" to MW -1 The sections show that silty clays & silty, clayey sands are present below 25' in most locations. A groundwater gradient map constructed from data collected on July 10 is shown as PLATE XXI, the gradient is to the east at approximately 351/1001, (18 5'/mile ) Data from other wells in the area have generally shown an easterly gradient Using the water analysis results from the hydropunch samples and monitoring wells, maps showing concentrations of benzene, toluene, ethylbenzene, xylene, TPHg, and TRPH as diesel were constructed, they are included as PLATES XXIII-A through XXIII-F Although the two methods of sampling are not strictly compatible, and the dates they were taken are different, both sets of data were used for constructing the maps If the results of the water sample taken from auger hole "A" are accurate, the high levels of gasoline compounds measured may either be due to contamination encountered during removal of the leach field, or to an offsite source We have not yet made a search to determine if such a source or sources exist It does not appear that the high levels of gasoline compounds are associated with either the removed waste oil tank or the three diesel tanks which were removed from the east side of the shop building The minor amounts of benzene, toluene, & xylene encountered in MW -1, located downgradient from the removed diesel tanks, is not inconsistent with compounds found in diesel TPH as gasoline was not detected in the water, but significant levels of TRPH as diesel were measured. TRPH as diesel was also measured in the 13