|
,(Vv:ATc
<br /> A s S o c I A T E S I N C
<br /> from approximately 55 feet to 57 feet bgs consisted of very stiff fine-grained material Sol] from
<br /> approximately 57 to 73 feet bgs generally of consisted of silty sand and sandy silt The boring log
<br /> ' from Fisch Environmental and supporting documentation are contained in Appendix B
<br /> 3_2 Hydrogeology
<br /> ' Water level measurements were collected from wells MW1 through MW7 on December 12 2001
<br /> 1 Water levels in groundwater monitoring wells NMI through MW7 ranged from 51 97 to 52 77
<br /> feet below the tops of the well casing elevations representing a decrease in the water elevation of
<br /> 4 25 feet since June 2001 The water level data were used to develop the groundwater elevation
<br /> contour map (Figure 4) Assuming that horizontal isotropic conditions prevail, groundwater in
<br /> the uppermost aquifer beneath the site flowed towards the south-southwest The average hydraulic
<br /> gradient on December 12, 2001 was calculated to be 0 0004 ft/ft or approximately 2 ft/mile A
<br /> summary of groundwater monitoring data is presented in Table 3
<br /> 4.0 DISTRIBUTION OF PETROLEUM HYDROCARBONS
<br /> 4.1 Petroleum Hydrocarbons in Soil
<br /> Soil samples collected from borings VEW 1, VEW2, MWS, MW6, and MW7 contained no
<br /> detectable concentrations of TPHg, TPHk, TPHd, TPHmo, BTEX, MTBE, TAME, ETBE,
<br /> D1PE, TBA, 1,2-DCA, or EDB Soil samples collected from bonng VEW3 contained
<br /> ' concentrations of TPHg and BTEX, but no detectable concentrations of TPHk, TPHd, TPHmo,
<br /> MTBE, TAME, ETBE, DIPS, TBA, 1,2-DCA, or EDB Analytical results of soil samples are
<br /> summarized in Table 1 Laboratory data sheets and chain-of-custody documentation for soil
<br /> samples are presented in Appendix B
<br /> 4.2 Petroleum Hydrocarbons in Groundwater
<br /> 1 The groundwater samples collected on December 12 2001 from groundwater monitoring wells
<br /> ' MM3, MW4, MWS, MW6, and MW7 contained no detectable concentrations of TPHg, TPHd,
<br /> TPHk, BTEX, MTBE, TAME, ETBE, DIPE, TBA, 1,2-DCA, or EDB The groundwater
<br /> samples collected from groundwater wells MW1 and MW2 contained TPHg at concentrations of
<br /> ' 200 ppb and 500 ppb, respectively MTBE at a concentration of 25 ppb was detected in both
<br /> MW1 and MW2 The groundwater sample collected from well MW2 also contained low
<br /> concentrations of BTEX Isoconcentration maps depicting the lateral extents of TPHg, benzene,
<br /> and MTBE in shallow groundwater in December 2001 are shown on Figures 5, 6, and 7, - - -
<br /> respectively
<br /> The groundwater sample collected on December 13, 2001 from boring CPT1 contained no
<br /> detectable concentrations of TPHg, TPHd, TPHk, TPHmo, BTEX, MTBE, TAME, ETBE,
<br /> D1PE, TBA, 1,2-DCA, or EDB
<br /> w�62577nporlsVffik doc 6
<br />
|