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L & M OPERABLE UNIT- FIRST QUARTER 2012 SITE STATUS, REMEDIAL SUMMARY,
<br />AND GROUNDWATER MONITORING REPORT
<br />Groundwater Monitoring and Sampling
<br />April 30, 2012
<br />I:\Tidewater\TW Stockton (P2A)\QMRs\2012\1Q12\1Q12 QSSR QRSR QMR Stockton_FINAL.doc 2.22
<br />2.7.1.2 Fuel Oxygenates and Petroleum Hydrocarbon Concentrations
<br />A summary of 1Q12 shallow zone concentration trends of TPHg, TPHd, TPHo, benzene, MtBE,
<br />and TBA in comparison to results reported during the 4Q11 are presented in the table below.
<br />Values in parentheses represent number of detections and non-detections that were reported in
<br />the 4Q11.
<br />Constituent
<br />Wells
<br />Concentrations
<br />Increased
<br />Number
<br />of Wells
<br />Concentrations
<br />Increased
<br />Wells
<br />Concentrations
<br />Decreased
<br />Number
<br />of Wells
<br />Concentrations
<br />Decreased
<br />Wells With
<br />Stable or Non-
<br />Detectable
<br />Concentrations
<br />Number
<br />of Wells With
<br />Stable or
<br />Non-Detectable
<br />Concentrations
<br />TPHg MW-18, MW-20,
<br />MW-22 3 (0) MW-9, 2AMW-12 2 (5)
<br />MW-21, MW-23,
<br />MW-25, MW-28,
<br />MW-30, MW-31,
<br />MW-33, MW-34,
<br />MW-45
<br />9 (9)
<br />TPHd
<br />MW-9, 2AMW-12,
<br />MW-22, MW-30,
<br />MW-31, MW-33
<br />6 (6)MW-20, MW-21,
<br />MW-23, MW-34 4 (5)MW-18, MW-25,
<br />MW-28, MW-45 4 (2)
<br />TPHo MW-9 1 (6) MW-23 1 (1)
<br />2AMW-12,
<br />MW-18, MW-20,
<br />MW-21, MW-22,
<br />MW-25, MW-28,
<br />MW-30, MW-31,
<br />MW-33, MW-34,
<br />MW-45
<br />12 (7)
<br />Benzene -- 0 (1) MW-9 1 (0)
<br />2AMW-12,
<br />MW-18, MW-20,
<br />MW-21, MW-22,
<br />MW-23, MW-25,
<br />MW-28, MW-30,
<br />MW-31, MW-33,
<br />MW-34, MW-45
<br />13 (13)
<br />MtBE MW-9 1 (0) -- 0 (1)
<br />2AMW-12,
<br />MW-18, MW-20,
<br />MW-21, MW-22,
<br />MW-23, MW-25,
<br />MW-28, MW-30,
<br />MW-31, MW-33,
<br />MW-34, MW-45
<br />13 (13)
<br />TBA -- 0 (1) MW-9 1 (1)
<br />2AMW-12,
<br />MW-18, MW-20,
<br />MW-21, MW-22,
<br />MW-23, MW-25,
<br />MW-28, MW-30,
<br />MW-31, MW-33,
<br />MW-34, MW-45
<br />13 (12)
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