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%fps <br /> yrfr.�1 Third Quarter 1496 Slaws Report-Former Discovery Chevrolet <br /> September 23, 1496 <br /> MW-2 did not contain detectable concentrations of TPHg, however, benzene was detected <br /> in this sample at a concentration of 1.1 ppb. MTBE was not detected in the groundwater <br /> samples from wells MW-1 or MW-2. Low concentrations of TPHd (60 ppb) were detected <br /> in the groundwater sample from well MW-3, however, Cl-HCs were not detected in this <br /> sample. TPHg and BTEX were not detected in the trip blank. These data have been used <br /> to construct a TPHg/Benzene/TPHd Concentration Map (Figure 4). <br /> Disposition of Well Purge Water <br /> Purge water generated during the third quarter 1996 sampling of groundwater monitoring <br /> wells MW-1 through MW-3 was discharged to properly labelled drums and stored at the site <br /> pending disposal. <br /> DISCUSSION AND CONCLUSIONS <br /> During the third quarter 1996 groundwater was measured 0.89 to 0.97 feet below levels <br /> measured during the second .quarter 1995. During the third quarter 1996 groundwater. <br /> appeared 'to flow toward .the northwest under a gradient of 0.005. These data appear <br /> generally consistent with historical monitoring data. <br /> TPHg and benzene were detected in the upgradient well, MW-1. Benzene was detected in <br /> well MW-2, downgradient of the former gasoline USTs. A low concentration of TPHd was <br /> detected in well MW-3 downgradient.of the former waste oil UST. From second to third <br /> quarter 1996 hydrocarbon concentrations decreased dramatically in both wells MW-1 and <br /> MW-2: <br /> TPHg, BTEX, or Cl-HCs have never been detected in groundwater samples from well <br /> MW-3. Groundwater downgradient of the former waste oil UST in the vicinity of well <br /> MW-3 has not been impacted by these hydrocarbons. TPHd has been detected in well <br /> MW-3 during only three of the eight quarterly sampling events, at concentrations of 200, 60, <br /> and 60 ppb. <br /> NEXT QUARTER'S PLANNED ACTIVITIES <br /> Activities planned for the fourth quarter 1996 at the subject site include: <br /> • Monitoring, purging, and sampling all on-site groundwater monitoring wells. <br /> Groundwater samples from wells MW-1 and MW-2 will be analyzed for TPHg and <br /> BTEX. The groundwater. sample from well MW-3 will be analyzed for TPHd and <br /> CL-HC's. <br /> 8146.03-3 4 <br />