Laserfiche WebLink
v <br /> 0 <br /> A S S 0 C I A T E S I N C <br /> GROUNDWATER FLOW DIRECTION <br /> Water level measurements were collected from monitoring wells MW1, MW2, and MW3 on <br /> September 3, 2004 Water level elevations ranged from 35 18 to 35 29, representing an average <br /> decrease in water table elevation of approximately 0 92 feet since June 2004 The water level <br /> data were used to develop the groundwater elevation contour map (Figure 3) Assuming that <br /> horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site <br /> flowed toward the northwest The average hydraulic gradient on September 3, 2004, was <br /> calculated to be 0 0014 or approximately 7 5 ft/mile A summary of groundwater monitoring <br /> data is presented in Table 1 <br /> ANALYTICAL RESULTS <br /> TPHg was detected in the groundwater samples collected from wells MW1, MW2, and MW3 at <br /> concentrations of 740 micrograms per liter (pg/L), 1,100 pg/L, and 3,000 pg/L, respectively <br /> Benzene was detected in the groundwater samples collected from wells MW1, MW2, and MW3 <br /> at concentrations of 13 pg/L, 2 4 pg/L, and 2 0 pg/L., respectively Toluene, ethyl benzene and <br /> xylenes were detected in the groundwater samples collected from wells MW 1, MW2, and MW3 <br /> at a concentrations ranging from 0 9 pglL to 57 pg/L MTBE was not detected in the <br /> groundwater samples collected from wells MW 1, MW2, and MW3 Analytical results of <br /> groundwater samples are summarized in Table 2 <br /> CONCLUSIONS <br /> Groundwater flow direction and gradient is generally consistent with previous sampling events <br /> Water table elevations have generally decreased and were measured at the lowest level recorded <br /> since monitoring was initiated at the site in 1999 Groundwater analytical results indicate that the <br /> concentrations of benzene detected in the samples collected from the monitoring wells have <br /> recently increased but remain within historical parameters as set by previous groundwater <br /> analytical results This may be due to a rebounding effect following groundwater extraction <br /> activities and/or the historical low groundwater table <br /> RECOMMENDATIONS <br /> Based on the results of the third quarter 2004 monitoring event indicating low concentrations of <br /> benzene in groundwater samples collected from MW 1 through MW3, we recommend the site be <br /> considered for closure <br /> s%envronmentai1149811Reports'aQR-04 doe 3 <br />