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i
<br /> Pacific Gas and 't_
<br /> & Electric Company 'tt
<br /> Fechnicai and Ecological Services 3400 Crow Canyon Road
<br /> June 22, 1999 t { ') P i"`} San Ramon,CA 945K
<br /> 925.820.2000
<br /> Mr. Kit Custis
<br /> California Regional Water Quality Control Board
<br /> Central Valley Region
<br /> 3443 Routier Road, Suite A
<br /> Sacramento,CA 95827-3003
<br /> RE: First Quarter 1999 Groundwater Monitoring Report
<br /> PG&.E's McMullin Gas Dehydrator Station,Manteca, CA
<br /> Dear Mr. Curtis:
<br /> Enclosed is the first quarter 1999 groundwater monitoring report for PG&E's McMullin Gas Dehydrator Station. In August
<br /> 1998,a compound formulated by Regenesis®called Oxygen Releasing Compound(or ORC)was injected at this site to
<br /> enhance biodegradation rates in the subsurface.
<br /> The following is a summary of field and laboratory results performed in February 1999:
<br /> • TPH-gas,TPH-diesel,TPH-motor oil, and BTEX were not detected in the samples collected from well MW-1,
<br /> MW-3,MW4 and MW-8.
<br /> • TPH-gas were detected in the samples collected from well MW-2,MW-5,MW-6 and MW-7 at concentrations of
<br /> 4,200 micrograms per liter(gg/L), 350 gg/L, 3,000 gg/L, and 340 gg/L, respectively.
<br /> • TPH-diesel were detected in the samples collected from well MW-2,MW-5,MW-6 and MW-7 at concentrations of
<br /> 3,400 gg/L, 1,300 gg/L, 7,800 pg/L,and 320 gg/L, respectively.
<br /> • TPH as motor oil were not detected in any of the samples.
<br /> ,• Benzene was detected in the samples collected from well MW-2,MW-5,MW-6 and MW-7 at concentrations of
<br /> 27 gg/L, 18 pg/L, 59 gg/L, and 2.3 gg/L, respectively.
<br /> • Toluene was detected in the samples collected from well MW-2,MW-5,MW-6 and MW-7 at concentrations of
<br /> 27 gg/L, 2.6 gg/L, 11 µg/L,and 0.89 gg/L, respectively.
<br /> • Ethylbenzene was detected in the samples collected from well MW-2,MW-5,MW=6 and MW-7 at concentrations
<br /> of 160 pg/L, 10 gg/L,350 4g/L,and 5.6 gg/L, respectively.
<br /> • Total xylenes were detected in the samples collected from well MW-2,MW-5;MW-6 and MW-7 at concentrations
<br /> of 760 gg/L, 8.4 gg/L, 350 pg/L,and 2.9 gg/L, respectively.
<br /> • The direction of groundwater flow was to the south,with a hydraulic gradient of approximately 0.002 foot per foot.
<br /> Pleasc call Eric Johnson at(925)866-5888 if you wish to discuss this site.
<br /> Sincerely,
<br /> C
<br /> Chi C. Lee
<br /> Chemist
<br /> 402 331-99 116/115.doc
<br /> PC: Ivlr._JeffeQ—Wgi
<br /> San Joaquin County Public Health Services
<br /> Environmental Health Division
<br /> 804 East Weber Avenue
<br /> Stockton, CA 95202
<br /> Enclosure
<br />
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