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U-Haul#709-50
<br /> Preliminary Site Conceptual Model Blaes Environmental
<br /> December 15,2006
<br /> 44.6 Findings
<br /> The following observations are based on laboratory analytical results from the additional groundwater
<br /> assessment activities conducted in March 2006 and the subsequent groundwater monitoring events (including
<br /> the additional groundwater monitor wells MW-13B, MW-13C, MW-14B, and MW-14C)
<br /> • Total Petroleum Hydrocarbons-Gasoline Range The lateral extent of TPHg in groundwater in the
<br /> shallow (B) zone and deep (C) zone appears to be defined by monitor wells MW-5(B&C),
<br /> MW-8(B&C), MW-10(B&C),MW-I 1(B&C), MW-12(B&C), MW-I3(B&C), and MW-14(B&C)
<br /> 0 Total Petroleum Hydrocarbons - Diesel Range The Iateral extent of TPHd in groundwater in the
<br /> shallow (B) zone appears to be defined by monitor wells MW-5B, MW-8B, MW-IOB, MW-IIB,
<br /> MW-12B, MW-1313, and MW-14B The lateral extent of the ma)onty of the mass of TPHd in
<br /> groundwater in the deep (C) zone appears to be largely defined by monitor wells MW-5C, MW-8C,
<br /> MW-IOC, MW-IIC, MW-12C, MW-13C, MW-14C, and soil boring DP-9, however, low
<br /> concentrations of TPHd ranging from 72 to 330 ppb were detected in the above listed monitor wells
<br /> with the exception of MW-I3C
<br /> Benzene The lateral extent of benzene in groundwater in the shallow (B) zone and deep (C) zone
<br /> appears to be defined by monitor wells MW-5(B&C), MW-8(B&C), MW-10(B&C), MW-11(B&C),
<br /> MW-12(13&C), MW-13(B&C), MW-14(B&C), and soil boring DP-9 Although 084 ppb benzene
<br /> was detected in monitor well MW-I IC in September 2006, it is probable that the lateral extent of
<br /> benzene in the deep (C) zone to the west of the U-Haul site is near the location of MW-11 C based on
<br /> the low benzene concentration
<br /> • 1,2 DCA The lateral extent of 1,2 DCA in groundwater in the shallow (B) zone appears to be
<br /> largely defined by monitor wells MW-5B, MW-IOB, MW-I IB, MW-12B, MW-13B, MW-I4B, and
<br /> DP-9, however, 0 76 ppb 1,2 DCA was detected in monitor well 1 IB in September 2006 The lateral
<br /> extent of the majority of the mass of 1,2 DCA in groundwater in the deep (C) zone appears to be
<br /> largely defined by monitor wells MW-5C, MW-8C, MW-IOC, MW-IIC, MW-12C, MW-13C,
<br /> MW-14C, and soil boring DP-9, however, concentrations of 1,2 DCA (ranging from 0 8 in DP-9 to
<br /> • 4 4 ppb and 9 I ppb in MW-13C and MW-I IC, respectively) were detected in the deep (C) zone
<br /> toward the northwest, west, and southwest from the U-Haul site It should be noted that
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