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<br /> FlaPacific Gas and
<br /> Electric Company - , 1 + - r"I- F i
<br /> fir. �;',` if ���- 1Technical and Ecological Services 3400 Crow Carryon Road
<br /> San Ramon,CA 94583
<br /> UO NO _6 Pp1 1-
<br /> ! 975,820.2000
<br /> October 26, 2000 f� {
<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: Third 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 Third Quarter 2000 Groundwater Monitoring Report for Pacific Gas and Electric Company's
<br /> McMullin Gas Dehydrator Station. 1n 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 August 2000:
<br /> • TPH-gas, TPH-diesel, and BTEX were not detected in the samples collected from wells MW-1, MW-3,
<br /> MW-4, MW-8, PZ-1 and PZ-4.
<br /> • Unknown gasoline-range petroleum hydrocarbons were detected in the samples collected from wells
<br /> MW-2, MW-5, MW-6, and MW-7 at concentrations of 930 micrograms per liter(gg/L), 310 µg/L, 1,900
<br /> pg/L, and 820 µg/L, respectively.
<br /> • Early diesel-range hydrocarbons were detected in the samples collected from wells MW-2, MW-5, MW-6,
<br /> and PZ-4 at concentrations of 740 gg/L, 360 µg/L, 1,200 µg/L, and 380 µg/L, respectively.
<br /> • Benzene was detected in the samples collected from wells MW-2, MW-6, and MW-7 at concentrations
<br /> of 9.7 µg/L, 18 lag/L, and 120 4g/L, respectively.
<br /> • Toluene was detected in the samples collected from wells MW-2 and MW-7 at concentrations of 19
<br /> µg/L and 2.1 pg/L, respectively.
<br /> • Ethylbenzene was detected in the samples collected from wells MW-2, MW-6, and MW-7 at
<br /> concentrations of 44 µg/L, 150 µglL, and 11 p.g/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 90 �Lg/L, 1.7 dig/L, 150 µg/L, and 28 PLg/L, respectively,
<br /> • Lead was detected for the first time in the samples collected from wells MW-5, PZ-1, and PZ-4 at
<br /> concentrations of 0.0059 milligrams per liter(mg/L), 0.0051 mg/L, and 0.0053 mg/L, respectively. The
<br /> method detection limit for this analyte is 0.0050 mg/L.
<br /> • The direction of groundwater flow was to the west-southwest,with a hydraulic gradient of approximately
<br /> 0.003 foot per foot.
<br /> 402 331-00 220.doc
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