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.y <br /> 12 was ND for the second consecutive quarter, indicating that the 280 ppb (TPH as <br /> . gasoline) detected in March 1994 may have been an anomaly or laboratory contamination <br /> 5.4 Volatile Halocarbon Contamination <br /> 1,2-Dichlorethane(DCA)was detected in samples from MW-7, MW-9, MW-12 and MW-14, <br /> continuing the trend of intermittent detection at the site. However, DCA has been detected <br /> - in samples from MW-13 and MW-14 for five consecutive quarters. The source of the DCA <br /> continues to be questionable <br /> Chloroform was detected in samples from wells EW-1, MW-7 and MW-14 The source of <br /> the chloroform is unknown, however, chloroform is common in drinking water, though no <br /> Maximum Contaminant Level (MCL) or Action Level (AL) for drinking water has been <br /> established by the State of California. <br /> We recommend that halogenated volatile organic compounds (HVOC's) be dropped from <br /> the monitoring requirements for wells MW-6, MW-10, MW-11 and MW-12, because no <br /> HVOC's have been detected in these wells for more than a year All other rxells should <br /> continued to be sampled for HVOC's <br /> 5.5 Ethylene Dibromide (EDB) <br /> Over the past five quarters, EDB has only been detected in samples from ?BIW-14 It <br /> appears that EDB impacted groundwater at the site has been limited to the immediate <br /> vicinity of MW-14, no migration has been obsened Therefore, we recommend that EDB <br /> be dropped from the monitonng program <br /> 5.6 Soluble Lead <br /> Lead was detected at very low concentrations in samples from MW-11 and MW-12 All <br /> concentrations detected during the past year have been below the MCL for lead, which is <br /> 0 05 mg/L Therefore, lead does not appear that lead poses a potential threat to <br /> groundwater at this site and should be deleted from the monitonng program <br /> 6.0 LIMITATIONS <br /> Our professional services were performed using that degree of care and skill ordinarily <br /> exercised by environmental consultants practicing in this or similar localities The findings <br /> were based upon analytical results provided by an independent laboratory Evaluations of <br /> the geologic/hydrogeologic conditions at the site for the purpose of this investigation are <br /> made from a limited number of available data points (i e. monitoring wells) and subsurface <br /> conditions may vary away from these data points No other warranty, expressed or implied, <br /> is made as to the professional recommendations contained in this report <br /> Ga I-P-t Ay,S.--I 1— 7 <br /> Q..M'r Y ReF.,9 M.33 UBWQMS <br />