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0 A S S D C I A T E S I N C ANALYTICAL RESULTS TPHg and BTEX were detected above laboratory method detection limits in the samples collected from wells MW1, MW3, MWS, MW6, and MW7 The samples collected from wells MW2, MW4, and CW contained no detectable concentrations of petroleum hydrocarbons Groundwater samples from wells MWI, MW3, and MW7 continue to contain elevated concentrations of TPHg and BTEX A summary of analytical results is presented in Table 1 Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 GROUNDWATER FLOW DIRECTION Water level measurements were collected from wells MWI through MW7, and CW on October 5, 1999 Water levels ranged from 21 31 to 24 25 feet below the tops of the well casing elevations, representing an average decrease in the water table elevation of approximately 0 65 feet since August 1999 The water level data were used to develop the groundwater elevation contour map (Figure 3) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site flowed towards the northeast The average hydraulic gradient on October 5, 1999 was calculated to be 0 007 ft/ft or approximately 37 ft/mile A summary of groundwater monitoring data is presented in Table 1 CONCLUSIONS Concentrations from wells MWI through MW7 and CW remain consistent with the results from previous sampling events It appears as though there are petroleum hydrocarbons remaining in the soil The direction of groundwater flow and the magnitude of hydraulic gradient are consistent with the previous event Groundwater elevations have decreased since August 1999 RECOMMENDATIONS Based on the results of the Third quarter 1999 monitoring episode,we recommend the following o Conduct the Fourth Quarter 1999 groundwater monitoring and sampling wells MWI through MW7 and CW and analyze samples for TPHg and BTEX by EPA Method 8020 0 w 1625961quartlyl3gr-1999 doc 3