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Pacific Gas and
<br /> Electric Company
<br /> Technical and Ecological Services 3400 Crow Canyon Road
<br /> San Ramon,CA 94583
<br /> f {r{1 1 I Q r �: l� 325.820.2000
<br /> January 8, 2001 J 0 .
<br /> Ms. Mary Serra
<br /> California Regional Water Quality Control Board
<br /> Central Valley Region
<br /> 3443 Routier Road, Suite A
<br /> Sacramento, CA 95827-3003
<br /> Re: Fourth Quarter 2000 Groundwater Monitoring Report
<br /> Pacific Gas and Electric Company's McMullin Gas Dehydrator Station,Manteca, CA
<br /> Dear Ms. Serra:
<br /> Enclosed is the Fourth Quarter 2000 Groundwater Monitoring Report for Pacific Gas and Electric Company's
<br /> McMullin Gas Dehydrator Station. In August 1998, a compound formulated by Regenesis®called Oxygen
<br /> Releasing Compound (or ORC)was injected at this site to enhance biodegradation rates in the subsurface.
<br /> The following is a summary of field and laboratory results performed in November 2000:
<br /> • TPH-G, TPH-D, and BTEX were not detected in the samples collected from wells MW-1, MW-3 and
<br /> MW-8.
<br /> • Unknown diesel-range petroleum hydrocarbons were detected in the samples collected from wells
<br /> MW-4, PZ-1, and PZ-4 at concentrations of 120 micrograms per liter(µg/L), 57 µg/L, and 73 µ.g/L
<br /> respectively.
<br /> • Early diesel-range hydrocarbons were'detected in the samples collected from wells MW-2, MW-5, MW-6,
<br /> and MW-7 at concentrations of 1200 µg/L, 800 µg/L, 2400 µg/L, and 3100 µg/L,respectively.
<br /> • TPH-G was detected in the samples collected from wells MW-2, MW-5, MW-6 and MW-7 at
<br /> concentrations of 4300 micrograms per liter(pg/L), 350pg/L, 5000 Ag/L and 5200 pg/L, respectively.
<br /> • Benzene was detected in the samples collected from wells MW-2, MW-5, MW-6, and MW-7 at
<br /> concentrations of 130 µg/L, 5.3µ.g/L, 110 µg/L; and 610 µg/L, respectively.
<br /> • Toluene was detected in the samples collected from wells MW-2, MW-6, and MW-7 at concentrations
<br /> of 26 µg/L, 31 !tg/L, and 27 µg/L, respectively.
<br /> • Ethylbenzene was detected in the samples collected from wells MW-2, MW-6, and MW-7 at
<br /> concentrations of 550 gg/L, 280 µg/L, and 490 µg/L, respectively.
<br /> • Total xylenes were detected in the samples collected from wells MW-2, MW-5, MW-6, and MW-7 at
<br /> concentrations of 860 ug/L, 4.2 µg/L, 450 �Lg/L, and 750 µg/L, respectively.
<br /> • Lead was not detected in any of the samples collected.
<br /> • The direction of groundwater flow was to the west-southwest, with a hydraulic gradient of approximately
<br /> 0.002 foot per foot.
<br /> 402_331-D! 9.doc
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