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08 March 2005
<br /> AGE-NC Project No. 02-0962
<br /> Page 3 of 9
<br /> TPH was detected in samples BI-35 and Bl-40 at concentrations of 68,000 µg/kg and
<br /> 193,000 µg/kg, respectively.
<br /> On 19 October 1985, monitoring well MW-1 was developed and ground water samples were
<br /> collected for analysis. The samples were transported to CWL and analyzed for:
<br /> • BTEX,chlorobenzene, l,2-dichlorobenzene, l,3-dichlorobenzene,and 1,4-dichlorobenzene
<br /> by EPA Method 602; and
<br /> • TPH and total lead.
<br /> BTEX compounds were detected at concentrations of 21.2 micrograms per liter (µg/l: parts per
<br /> billion) benzene, 204 µg/1 toluene, 12.4 µg/1 ethylbenzene, and 1,440 µg/1 total xylenes. TPH was
<br /> detected at a concentration of 16,000 µg/1; total lead was detected at a concentration of 110 µg/l.
<br /> Analytical results of soil and ground water samples taken on 16 and 19 October 1985 are
<br /> summarized in Table 1.
<br /> On 24 April 2001,ground water in monitoring well MW-1 was sampled by Central Valley Regional
<br /> Water Quality Control Board (CVRWQCB) personnel and analyzed by California Laboratory
<br /> Services (CLS) for:
<br /> • BTEX, di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), methyl tertiary-butyl
<br /> ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary-butyl alcohol (TBA), 1,2-
<br /> dichloroethane (1,2-DCA), and 1,2-dibromoethane(EDB); and
<br /> • 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, isopropylbenzene, naphthalene, n-
<br /> butylbenzene,n-propylbenzene,p-isopropyltoluene,sec-butylbenzene,and tert-butylbenzene.
<br /> BTEX was detected at concentrations of 49µg/1 benzene,540 µg/l toluene, 590 µg/1 ethylbenzene,
<br /> and 2,300 µg/1 xylenes.
<br /> 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene,isopropylbenzene,naphthalene,n-propylbenzene,
<br /> p-isopropyltoluene, and sec-butylbenzene were detected at concentrations of 520 µg/l, 400 µg/1,
<br /> 34 µg/1, 180 µg/1, 85 µg/1, 13 µg/1, and 390 µg/1,respectively.
<br /> 2.4 STRATIGRAPHY
<br /> Generally,fine-grained,gray-brown,damp,silty sand was encountered in boring MW-1 from surface
<br /> grade to 5 feet bsg.From 10 feet to 30 feet bsg,fine-to medium-grained,blue-gray to yellow-brown,
<br /> Advanced GeoEnvironmental,Inc.
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