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URS
<br /> Mr. James Barton Page 6 of 8
<br /> California Regional Water Quality Control Board, Central Valley Region
<br /> ' April 29, 2010
<br /> 1,2-Dichloropropane was detected in MW-17 at a concentration of 0.7 gg/L. 1,3,5-trimethylbenzene was
<br /> detected in MW-16 (1.9 gg/L),MW-17 (0.7 gg/L), and E-1 (0.6 gg/L). 1,2,4-trimethylbenzene was
<br /> detected in MW-16(6.9 gg/L),MW-17(2.4 gg/L),and E-1 (2.1 gg/L).Propylbenzene was detected in
<br /> MW-16 at a concentration of 0.9 gg/L.
<br /> MTBE was also reported in the influent samples from 17717(13 gg/L), 17821 (17 gg/L), 17899(1.9
<br /> gg/L), 17911 (17 gg/L), 17926 (3.9 gg/L), 17933 (1.8 gg/L),and 17950(71 µg2).Figure 10 shows the
<br /> ' domestic well sampling locations, as well as MTBE concentrations.MTBE concentrations for 17717-
<br /> INF was the highest concentration historically.MTBE was also detected in the 17717-GAC 1 sample at a
<br /> concentration of 8.1 gg/L.MTBE concentrations for 17821-INF continues to decrease since June 2009.
<br /> In 17950-GAC1,MTBE was detected at 1.2 gg/L,but 17950-EFF was non-detect.
<br /> Groundwater monitoring data are presented in Table 3.The laboratory analytical data report,including
<br /> ' the full list of analyzed VOCs and chain-of-custody documentation, are provided in Attachment B.
<br /> Groundwater analytical data were submitted electronically to the State Water Resources Control Board
<br /> GeoTracker System per Article 12, Chapter 17,Division 3,Title 23 of the California Code of
<br /> Regulations. Geotracker upload confirmation sheets are included as Attachment C.
<br /> CONCLUSIONS
<br /> Based on the results of groundwater monitoring activities,URS concludes the following:
<br /> • In E-1,TPH-G was detected for the first time,historically,at a concentration of 85 µg2.
<br /> ' Benzene,toluene,ethylbenzene,total xylenes(BTEX)were also detected in E-1, for the first
<br /> time historically. These concentrations ranged from 2.2 gg/1 to 17.1 gg/L.
<br /> • TPH-D was detected in wells E-1,MW-3,MW-5,MW-6,MW-13,MW-14, MW-16,MW-17,
<br /> MW-19, MW-20,RW-2, and RW-3 in concentrations ranging from 51 micrograms per liter
<br /> (gg/L) and 1,300 gg/L. These results have been"J"flagged.The J flag was applied because the
<br /> samples exhibited chromatographic patterns which did not resemble the"diesel" standard.
<br /> • MTBE was reported in samples from wells MW-13 (0.5 gg/L),MW-17 (0.8 gg/L), and MW-19
<br /> (1.0 µg2).
<br /> • In MW-16,TPH-G was detected at 170 gg/L. TPH-G,benzene,toluene,and total xylenes were
<br /> detected at the highest concentrations since the July 2003 sampling event.TPH-G was detected
<br /> at the highest concentration historically in MW-17, at a concentration of 82 gg/L.In MW-17,
<br /> BTEX was detected at the highest concentrations historically.
<br /> MTBE was also reported in the influent samples from 17717(13 gg/L), 17821 (17 gg/L), 17899
<br /> (1.9 gg/L), 17911 (17 gg/L), 17926(3.9 gg/L), 17933 (1.8 gg/L),and 17950(71 gg/L).Figure
<br /> 10 shows the domestic well sampling locations, as well as MTBE concentrations.MTBE
<br /> concentrations for 17717-INF was the highest concentration historically. MTBE was also
<br /> detected in the 17717-GAC1 sample at a concentration of 8.1 gg/L.MTBE concentrations for
<br /> ' 17821-INF continues to decrease since June 2009. In 17950-GAC 1,MTBE was detected at 1.2
<br /> gg/L,but 17950-EFF was non-detect.
<br /> HAWprocess\RESD\Franks One Stop\QTR 10\IQMR10 Report.doc
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