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Mr Terry Tarditi y November 2, 2004 Page 3 ' DISCUSSION Based on the thirdquarter's data, the groundwater hydraulic gradient remains relatively flat,with a hydraulic gradient of 0 001 feet per foot, as shown in tFigure 2 BTEX The reporting ltimts for all constituent concentrations in MW-1 were increased to 15 micrograms per liter (µg/L) from 0 5 jig/L due to known high concentrations of MtBE The 15 �Lg/L is a decrease from the 25 µg/L reporting for the second quarter The dilutions were necessary because the MtBE concentrations were out of the calibration range for the target analyte Samples from MW-1 are analyzed multiple tunes by the analytical laboratory to bring the correct dilution into the calibration range The reporting limit for MW-4 was increased from 0 5 µg/L to 1 µg/l-- also in response to MtBE concentrations BTEX concentrations were below their respective reporting limits in all of the wells These results are consistent with previous quarters Per the PHS/EHD's request, BC will work with the analytical laboratory to determine if it is feasible to quantify the BTEX constituents without damaging the equipment 1 TPH-g. TPH-g concentrations were detected below the method reporting limits of 50 µg/L in MW-2 and 100 µg/L MW-4 In well MW-1, the TPH-g reporting limit decreased from 2,500 µg/L in the 2nd quarter to 1,500 µg/L this quarter without detectable concentrations reported in the sample TPH-g concentrations were not detected above the reporting limit of 50 µg/L in MW-3 - the first time since sampling began in 1998 MtBE MtBE concentrations were detected in samples from all four monitoring wells MtBE has never been detected in samples from the Supply Well In MW-1, MtBE concentrations decreased from 62,000 µg/L m the second quarter 2004 to 55,000 �Lg/L this quarter Low MtBE concentrations were detected in MW-2 at 4 7 µg/L MtBE concentrations decreased from the second quarter 2004 levels in MW-3 from 38 }ig/L to 17 µg/L and in MW-4 from 570 n/L to 480 µg/L, however, these MtBE concentrations tend to fluctuate slightly I lot,,rporA rsarprpa,rd rrr aafm&nm„alb At rlandardi o111x rudurlr)al dx time a av(prrpared If Should nn!be rrlred upon b)palrer a11xr 11vn Awre Jor w1 nm rl rvai p,rparrd and fbrn an6 to!lu extent&I11x reope of xvrk which xwf aufhon;rd F111 c ,rpoa doer,m1 ualwilee 11vt Gel mud flx,1 dewnbed w/&f rrporf evifr u1 I&ate 11\21(HH)\21417 '1&1\Report~\3rd-04gtr doc