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04kTc <br /> . A S S O C l A 7 E S I N C <br /> and groundwater samples contained detectable concentrations of petroleum hydrocarbons Field <br /> activities and analytical results were detailed in ATC's Summary Report of Additional Subsurface <br /> Investigation, dated January 8, 1999 <br /> SAMPLING ACTIVITIES <br /> On April 2, 1999, a groundwater sample was collected by ATC personnel from monitoring well <br /> MW1 The location of the monitoring well is shown on Figure 2 Prior to collection of the <br /> groundwater sample, the depth to water, pH, electrical conductivity, and temperature were <br /> measured in the monitoring well and recorded A minimum of three well casing volumes was <br /> purged from the well prior to sampling The well was allowed to recover and a sample was <br /> collected from the well using a dedicated disposable bailer <br /> The groundwater sample collected from the well was submitted to State-certified Sequoia <br /> Analytical (ELAP Cert No 1210) for chemical analysis of total petroleum hydrocarbons as <br /> gasoline (TPHg), total petroleum hydrocarbons as diesel (TPHd), total petroleum hydrocarbons <br /> as kerosene (TPHk), benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA 8015 and <br /> 8020 methodologies, and oxygenate fuel additives utilizing EPA 8260 methodology <br /> Groundwater well purge and sample logs are contained in Attachment I <br /> ANALYTICAL RESULTS <br /> The groundwater sample collected from well MW1 contained detectable concentrations of TPHg, <br /> TPHd, TPHk, benzene, xylenes, and methyl tertiary butyl ether (MTBE) No other oxygenate <br /> fuel additives, besides MTBE, were detected above laboratory method detection limits including <br /> ethanol, t-butanol, dl-isopropyl ether, ethyl t-butyl ether, and t-amyl methyl ether Analytical <br /> results for groundwater are summarized in Table 2 Laboratory data sheets and chain-of-custody <br /> documentation are contained in Attachment 2 <br /> GROUNDWATER ELEVATION <br /> A water level measurement was collected from well MW 1 on April 2, 1999 The: depth to water <br /> was measured at 46 40 feet below the top of the well casing elevation, representing an increase in <br /> the water table elevation of approximately 3 69 feet since September 1998 A summary of <br /> groundwater monitoring data is presented in Table 1 <br /> CONCLUSIONS <br /> Concentrations from well MW l have increased since the previous sampling event The <br /> groundwater elevation has increased since September 1998 <br /> • <br /> w 162577VWoM\2gr-1999 doe 2 <br />