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CV,AT C <br /> A S S O C I A T E S I N C <br /> average hydraulic gradient on March 24, 2005, was calculated to be 0.0064 ft/ft, or <br /> approximately 33.8 ft/mile. A summary of groundwater monitoring data is presented in Table 1. <br /> ANALYTICAL RESULTS <br /> The groundwater sample collected from MW4 contained detectable concentrations of TPHg, <br /> benzene, and ethyl benzene [510 micrograms per liter(ug/L), 19 ug/L, and 15 ug/L, respectively]. <br /> Groundwater samples collected from MW5 and MW8 contained detectable concentrations of <br /> benzene (0.7 ug/L and 0.6 ug/L, respectively). Groundwater samples collected from MW1, <br /> MW6, and MW7 contained no detectable concentrations of TPHg or BTEX constituents. <br /> Groundwater samples collected from MW1, MW4, MW5, MW6, MW7, and MW8 contained <br /> detectable concentrations of MTBE at 10 ug/L, 270 ug/L, 430 ug/L, 370 ug/L, 4.6 ug/L, and <br /> 2,100 ug/L, respectively. <br /> Analytical results of groundwater samples are summarized in Table 2. Laboratory data sheets <br /> and chain-of-custody documentation are contained in Attachment 2. An isoconcentration map <br /> depicting the MTBE concentrations in on-site wells during the first quarter 2005 is shown on <br /> Figure 4. <br /> GEOTRACKER DATA-UPLOAD <br /> The facility has been assigned a Geotracker global identification number T0607700120. The <br /> depth.to water data was submitted electronically to the State Water Resources Control Board <br /> (SWRCB) Geotracker database (confirmation number 4590789616). The laboratory data was <br /> also submitted electronically to the SWRCB Geotracker database (confirmation number <br /> 6531653225). Documentation of the data-submittal is contained in Attachment 3. <br /> CONCLUSIONS <br /> Chemical contaminant concentrations from MW1 and MW4 through MW8 generally remain <br /> consistent with�the results from the previous sampling event. The direction of groundwater flow <br /> was fairly consistent with respect to the previous monitoring event. The gradient on March 24, <br /> 2005, was 0.0064 &ft or' approximately 33.8 ft/mile. Groundwater elevations have decreased <br /> since December 2004. <br /> RECOMMENDATIONS <br /> Based on the results of the first quarter 2005 monitoring episode, we recommend the following: <br /> • Conduct the second quarter 2005 groundwater monitoring and sampling of MW1 and <br /> MW4 through MW8 and analyze samples for TPHg and BTEX by EPA Method <br /> s:lenviromental125847100371reportsllgr-2005.doc 4 <br />