ARCHIVED REPORTS XR0009481 - Laserfiche WebLink

Home Browse Search

AZURE ENVIRONMENTAL ' and August 1996 The ground-water level at MW-2 decreased approximately 1 S feet during the period from May 1996 to August 1996 ' Water table elevation data collected at the Site indicate the general direction of ground-water flow is toward the northeast, with local variations of flow direction in the area adjacent to the former tank locations at the Site (Figure 3) These data are generally consistent with potentiometnc data 1 and interpretations of ground-water flow direction at the Site presented in previous investigation reports Shallow ground water in the site vicinity flows toward the northeast under a hydraulic gradient of approximately 0 0015 ft/ft 3_2 Ground-Water Sampling and Laboratory Analysis ' On August 1, 1996, ground-water samples were collected from two downgradient monitoring wells at the Site (MW-9 and MW-10) The samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylene (BTEX), and ' methyl tertiary-butyl ether (MTBE) compounds Historical laboratory analysis results are summarized in Table 3, Iaboratory certificates are included in Appendix A and field sampling data ' sheets are included in Appendix B Most recent groundwater monitoring data of benzene concentrations in ground water are illustrated in Figure 4 The downgradient extent of petroleum hydrocarbons in ground water is monitored at wells MW-9 and MW-10 Monitoring data collected for wells MW-9 and MW-10 in August 1996 indicate BTEX and MTBE were not detected Only TPHg (110 ppb) was detected in well MW-10 ' These data are generally consistent with historical monitoring results, which indicate benzene has not been detected at MW-9 since January 1995 (0 6 ppb) and at MW-10 since October 1994 (0,6 ppb) These data continue to indicate the petroleum hydrocarbon plume has ' stabilized and is restricted to shallow ground water in the area adjacent to the former tank locations at the Site. I I I 2