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• A S S O C I A T E S I N C <br /> Groundwater samples from wells MW1, MW3, and MW7 continue to contain elevated <br /> concentrations of TPHg and BTEX A summary of analytical results is presented in Table 1 <br /> Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 <br /> GROUNDWATER FLOW DIRECTION <br /> Water level measurements were collected from wells MW1 through MW7, and CW on June 8, <br /> 2000 Water levels ranged from 19 82 to 22 50 feet below the tops of the well casing elevations, <br /> representing an average increase in the water table elevation of approximately 0 70 feet since <br /> March 2000 The water level data were used to develop the groundwater elevation contour map <br /> (Figure 3) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost <br /> aquifer beneath the site flowed towards the northeast The average hydraulic gradient on June 8, <br /> 2000 was calculated to be 0 004 ft/ft or approximately 21 ft/mile. A summary of groundwater <br /> monitoring data is presented in Table 1 <br /> ADDITIONAL SITE ACTIVITIES <br /> On April 7, 2000, ATC supervised the transport of 650 gallons of non-hazardous liquid waste <br /> purged from the groundwater wells during recent quarterly monitoring events Clearwater <br /> . Environmental transported the waste to the Alviso Independent Oil disposal facility in Alviso, <br /> California A copy of the non-hazardous waste manifest is contained in Attachment 3 <br /> i <br /> CONCLUSIONS <br /> Concentrations of TPHg and BTEX in wells MWI. through MW4, MW6, and CW remain <br /> consistent with the results from previous sampling events Concentrations of TPHg and BTEX <br /> in wells MW5 and MW7 appear to be decreasing It appears as though there are petroleum <br /> hydrocarbons remaining in the soil The direction of groundwater flow and the magnitude of <br /> hydraulic gradient are generally consistent with the previous event Groundwater elevations have <br /> increased since March 2000 <br /> RECOMMENDATIONS <br /> Based on the results of the Second Quarter 2000 monitoring episode, we recommend the <br /> following <br /> Conduct the Third Quarter 2000 groundwater monitoring and sampling wells MW1 <br /> through MW7 and CW and analyze samples for TPHg and BTEX by EPA Method 8020 <br /> w 162596%quart1yl2gr-2000 doc 3 <br />