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' — - ■� KI I INVILDER 8 CONCLUSIONS AND RECOMMENDATIONS 1 ' Kleinfelder conducted a sensitive receptor survey, push probe assessment and serm-annual groundwater sampling at the subject site Based upon our findings we have formulated the ' following conclusions and recommendations 1) A total of seven "sensitive receptors" were identified, which were potentially located within a ' 2,000-foot radius of a fonder underground storage tank (UST) at the subject site Six of the receptors were noted as wells and one an unlined canal Based upon groundwater sampling result in June and July 2000 and the distance and direction of these receptors from the former UST at the subject site, it is Kleinfelder's opinion that the contaminant plume at the subject site has not impacted these receptors ' 2) Groundwater flow direction during the July 7, 2000 Semi-Annual Sampling event was towards the northeast at a gradient of 0 005 ft/ft This flow direction and gradient are generally ' consistent with previous groundwater elevation data 3) Total petroleum hydrocarbons as referenced to gasoline and/or benzene were detected in groundwater samples collected from the three onsite monitonng wells (MW-1 through MW- 3) and one or more push probe groundwater samples (GP-3 through GP-5) located in the vicinity of the former UST None of the five oxygenates (ETBE, DIPE, MTBE, TAME or ' TBA) or ethanol and methanol were detected during the push probe assessment conducted on June 1, 2000 4) Benzene was detected in groundwater samples in each of the three onsite monitoring wells MW-1, MW-2 and MW-3 and in a single push probe groundwater sample The benzene concentrations ranged from 1 0µg/1 from groundwater collected from MW-2 to 1,100 µg11 ' from a groundwater sample collected from MW-1 These benzene concentrations are at or exceed State and Federal MCLS of 1 µg11 and 5 gg/l, respectively Petroleum constituents detected in groundwater from the three onsite monitoring wells have decreased from previous sampling events (See Table 1) ' 5) The contaminant plume appears be on the shape of an oval in the vicinity of the former UST and measures approximately 220 by 160 feet The plume appears to be contained at the subject site although the northern extent appears in close proximity to the northern border of ' the site near Industrial Drive 20-4439-01 801120008726 Page 14 of 17 ' Copynght 2000 Kleinfelder, Inc October 16,2000