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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 2.24
<br />SPH removal activities are scheduled to be conducted quarterly (at a minimum) for on and off
<br />Site wells which repeatedly contain measurable thickness of SPH or sheen. It should be noted
<br />that these SPH removal activities are typically performed between quarterly monitoring events
<br />(as noted on the table), and may influence reported SPH thickness.
<br />2.7.2.2 Fuel Oxygenates and Hydrocarbon Concentrations
<br />A summary of 1Q12 deep (B-, C-, and D-Zone) concentration trends of TPHg, TPHd, TPHo,
<br />benzene, MtBE, and TBA in comparison to results reported during the previous quarter are
<br />presented in the table below. Values in parentheses represent number of detections and
<br />non-detects that were reported in the 4Q11.
<br />Constituent Zone
<br />Wells With
<br />Increased
<br />Concentration
<br />Number
<br />of Wells
<br />Wells
<br />Concentrations
<br />Decreased
<br />Number
<br />of Wells
<br />Wells With
<br />Stable or Non-
<br />Detectable
<br />Concentrations
<br />Number
<br />of Wells With
<br />Stable or Non-
<br />Detectable
<br />Concentrations
<br />TPHg
<br />B MW-42, MW-51,
<br />MW-58, MW-59 4 (2) MW-29 1(3)
<br />MW-16, MW-24,
<br />MW-26, MW-27,
<br />MW-32, MW-35,
<br />MW-44, MW-56,
<br />MW-57, MW-60
<br />10 (10)
<br />C MW-54, MW-65,
<br />MW-66 3 (4) MW-64 1 (1)MW-61, MW-62,
<br />MW-63, MW-67 4 (3)
<br />D -- 0 (0)MW-55, MW-70,
<br />MW-72 3 (4)
<br />MW-68, MW-69,
<br />MW-71, MW-73,
<br />MW-74
<br />5 (4)
<br />TPHd
<br />B
<br />MW-24, MW-29,
<br />MW-32, MW-57,
<br />MW-58
<br />5 (12)
<br />MW-16, MW-26,
<br />MW-27, MW-35,
<br />MW-42, MW-44,
<br />MW-51, MW-56,
<br />MW-59, MW-60
<br />10 (2) -- 0 (1)
<br />C MW-63 1 (5)
<br />MW-54, MW-61,
<br />MW-62, MW-65,
<br />MW-67
<br />5 (1) MW-64, MW-66 2 (2)
<br />D MW-73 1 (4)
<br />MW-55, MW-68,
<br />MW-69, MW-70,
<br />MW-71, MW-72,
<br />MW-74
<br />7 (3) -- 0 (0)
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