Laserfiche WebLink
1 <br /> 1 <br /> 1 L.3 Assessment of Groundwater Contamination <br /> On January 18, 1990, boring MW-1 was completed as groundwater monitoring well MW-1 <br /> (RESNA 1993) Well construction details are presented on the well log located in Appendix V <br /> 1 On January 30, 1990, monitoring well MW1 was monitored, developed and sampled for BTEX, <br /> and TPHd by EPA 8020 and DOHS methods, respectively BTEX constituents were not present <br /> 1 above method detection limits, however, 150 parts per billion (ppb) TPHd was recorded in the <br /> sample <br /> 1 On January 2, 1991, two eight-inch soil borings were drilled and completed as groundwater <br /> monitoring wells MW2 and MW3 by Spectrum Exploration (C57 #512268) using a hollow stem <br />' auger drill rig (RESNA 1993) The wells, completed at a depth of approximately 23 feet bgs, <br /> were constructed of two-inch diameter F480 threaded PVC casing and 0 010 inch slot screen <br /> Well construction details are presented in the well logs located in Appendix V The locations of <br /> the wells are shown on Figure 2 <br />• On January 4, 1991 wells MW2 and MW3 were monitored, developed, purged and sampled in <br />' accordance with RESNA's QA/QC Plan (RESNA 1993) Water samples were analyzed by <br /> Applied Analytical and by Sequoia Analytical for BTEX and TPHd by appropriate EPA and DHS <br /> methodologies No detectable petroleum constituents were present in any of the samples (Table <br /> 1 3) <br /> 1 During paving operations at the site, monitoring well MW 1 was damaged and was subsequently <br /> abandoned in 1992 under permit from PHS/EHD (RESNA 1993) <br /> 1 Wells MW2 and MW3 have been monitored and sampled on a quarterly basis since January 4, <br /> 1 1991 (Tables 2 and 3) Purge logs and laboratory analysis reports for the last monitoring and <br /> sampling event in January 1994 are presented in Appendix IV Groundwater samples have been <br /> analyzed for BTEX, TPHd and total petroleum hydrocarbons as gasoline (TPHg) During the <br /> 1 thirteen rounds of groundwater sampling from well MW2 and MW3 (1190 to 1194), low levels of <br /> petroleum hydrocarbons have been detected only twice Based upon the lack of groundwater <br /> impact and the minimal volume of residual soil contamination (which should continue to decrease <br /> due to natural processes) no apparent threat to groundwater exists Episodes of degradation to <br /> w 19673Rmporls\Closure doe 3 <br /> • <br /> 1 <br /> SIYITH <br />