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S E C O R
<br />feet bgs and the bottom of casing is at 490 feet bgs. It is unknown if the well screen extends to
<br />total depth or ends prior to the 490 -foot depth. City of Lodi Municipal Well 12 was placed on
<br />emergency standby status in mid -2001 by the City of Lodi.
<br />G -R, Monitoring Well Installation Report (March 30, 2000)
<br />Between December, 1999 and February, 2000, V&W Drilling installed five additional monitoring
<br />wells (MW -5A, MW -6, MW -7, MW -8A, and MW -9 (now renamed as MW -9A]), four soil vapor
<br />extraction wells (VE -1 through VE -4), one groundwater extraction well (EX -1), and advanced
<br />two soil borings (SB -2 and SB -3) (Table 1). The field boring logs are contained in Appendix B.
<br />Soil samples collected from the borings were reported to contain concentrations of TPHg,
<br />benzene, and MtBE up to 1,740 mglkg, 446 mg/kg, and 100 mg/kg, respectively (Table 4). The
<br />highest concentrations were reported in samples from borings EX -1 and VE -1 located in the
<br />area of the former USTs. Groundwater samples collected from the monitoring wells and
<br />extraction well were reported to contain concentrations of TPHg, benzene, MtBE, EtBE, and
<br />TAME up to 51,000 µg11, 39,000 µg11, 720,000 µg/I, 18,000 µg11, and 6,000 µg/l, respectively
<br />(Table 3).
<br />SECOR, Problem Assessment Report (July 24, 2000)
<br />Between June 14 and July 7, 2000, ten groundwater monitoring wells (MW -5B, MW -8B,
<br />MW -10A and B, MW -11A and B, MW -12A and B, MW -13, and -EX -2) were installed at the site
<br />by Cascade Drilling (Table 1). Monitoring wells MW -56, MW -$B, MW -10B, MW -11B, and MW -
<br />12B were completed to approximately 90 ft bgs. Monitoring wells MW -10A, MWA 1A, MWA 2A,
<br />MWA 3, and EX -2 were completed to approximately 65 ft bgs. EX -2 was originally installed as a
<br />groundwater monitoring well and referred to as MW -14 on attached boring logs. The boring and
<br />well construction logs are contained in Appendix S.
<br />Concentrations of petroleum hydrocarbons and fuel oxygenates were not reported in soil
<br />samples collected from the borings for monitoring wells MW -5B, MW -813, MW -10A and B,
<br />MW -11A and B, MW -12A and B, and MW -13 (Table 4). MtBE was reported at a concentration
<br />of 0.189 mg/kg in the sample collected from 65 ft bgs in monitoring well EX -2.
<br />TPHg, benzene, toluene, ethyl -benzene, and xylenes (BTEX compounds) were not detected in
<br />r{ groundwater samples collected from monitoring wells MW -513, MW -8B, MW -10A and B, MW -
<br />11A and B, MW -12A and B and, MW -13 (Table 3). Benzene was reported in monitoring well
<br />+� EX -2 at a concentration of 1.02 µg/1. MTBE was reported in monitoring wells MW -5B, MW -10B,
<br />j and EX -2 at concentrations of 160 µg/1, 5.2 µg/1, and 1,100 µg/1, respectively. Concentrations
<br />of EtBE were reported in monitoring wells MW -5B and EX -2 at concentrations of 14 µg/I and
<br />r 120 µg/1, respectively. Ethanol was detected in monitoring wells MW -10B and MW -12B at
<br />concentrations of 1,400 µg/1 and 2,000 µg/I, respectively (Table 3).
<br />�_1 V
<br />95775 NFAR REPORT Final.doo 3 SECOR lntemational Incorporated
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