ARCHIVED REPORTS XR0001114 - Laserfiche WebLink

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' 90 ppm, 36 ppm, respectively, ethyl benzene was present at the same depths at levels of 6 9, 22, and 13 ppm, respectively Samples collected at 15 5', 20 5' 25 5, 30 5 and 35 5' contained xylenes at levels of 14, 6 8 430, 780, and 36 ppm, respectively Groundwater Analysis After boreholes B-1 through B-3 were converted to monitor wells MW-4 through MW-6, Artesian sampled the wells on May 15, 1992 Samples from MW-4 and MW-6 showed high levels of TPH-gasoline ranging from 11,000 parts per billion (ppb) to 6,500 ppb BTEX compounds were also present at high concentrations in both MW-4 and MW-6 Groundwater samples from MW-5 were non-detect for all the ' target chemicals As of February 22 1993 free product has been detected in monitor wells MW-1, MW-2, MW-3 and MW-6 It is presently found in MW-1, MW-2 and MW-6 Groundwater Gradient The monitor wells were surveyed by Duane C Kimball, of Modesto, California, a state-licensed surveyor The wells were surveyed to within 01 foot vertically and horizontally Groundwater flow direction appears to vary considerably on this site Review of the August, 1991 Kleinfelder Groundwater Assessment Report indicates that the initial groundwater gradient "slopes generally to the east but fluctuates from east-northeast to east-southeast" February 1991 data show groundwater to flow to the east April, 1991 data show groundwater to flow to the southeast ' For the May 15, 1992 event the groundwater flow direction was to the north northwest at a gradient of 0 0088 feet per foot The August 21, 1992 sampling event showed a similar gradient with groundwater flow to the south-southeast For the November 16, 1992 event, groundwater flow changed back to the north- northwest with a gradient of 0 015 feet/foot The most recent sampling event of February 22, 1993 shows that once again flow direction has changed, this time to the southeast directed gradient of 0 011 feet/foot L I