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Mr. Chris Dressel S61072.400.0002 January 27, 2014 Page 4 evaluating where off -Site sources may be contributing to the groundwater impacts that have been observed at the Site. In addition, groundwater samples from nested temporary locations at up to eight additional locations downgradient (i.e., north and east of the Site) are proposed to be collected from within City right -of -way in Lafayette Boulevard and in the vicinLWRI \W ",vy 7RwHr" SrRSHrWDnd from within City right -of -way in Main Street between the railroad tracks and Monroe Street to evaluate the downgradient distribution of chlorinated VOCs. In general, our proposed approach entails defining the vertical extent of chlorinated volatile organic compounds (VOCs) upgradient of AMW -1 S (shallow), AMW -11 (intermediate), and AMW -1 D (deep) (located at the immediate southwest corner of the Site) by installing four relatively shallow, intermediate, and relatively deeper temporary sampling points (installed at four nested sampling locations) within the area generally bounded by hendall Street (and alley to the west), Edward Street, Scott Street, and Indiana Avenue south and west of the Site; then installing relatively shallow and relatively deeper temporary sampling points in the vicinity of Lafayette Boulevard (4 nested sampling points) and Main Street (4 nested sampling points) as discussed above. This task will begin with the advancement of temporary screens using direct -push technologies (e.g., a ST- 15 Hydropunch) to a shallow depth (i.e., 26 to 30 feet below ground surface (bgs)), an intermediate depth of approximately 35 to 39 feet bgs, and, for upgradient locations, at a deeper depth of approximately 45 to 49 feet bgs, subject to approval of these IocationVlrRP V1N &O-bVVBRDrGRI 3uEU : RrIW(B3: ). The locations may be adjusted slightly in the field based on field observations such as utility locations, etc. Hull will work with the drilling subcontractor and the appropriate City and St. Joseph County authorities to arrange for access for the work and to clear utilities and to prepare appropriate permits for drilling in the right -of -way. Adjacent property owners will be notified by certified mail prior to the initiation of any drilling activities. Drill cuttings and sample purge and decontamination water will be containerized and placed at a location designated by the City. At each location where groundwater sampling is to be conducted, the borehole will initially be advanced to the deepest depth proposed for that location, at which point the outer casing of the sampling system will be withdrawn to expose a four foot long stainless steel wire wrapped screen. Once the screen is exposed, Hull will measure the static water level and lower a decontaminated Waterra foot -valve sampling pump or peristaltic pump to purge the equivalent of five well volumes of water to develop the aquifer surrounding the screen. Following extraction of each well volume, Hull will measure pH, temperature and conductivity to demonstrate that representative groundwater is being samplHd. ,n addition, Hull's rHprHsH ntativH will note if there is a visible sheen on the extracted water. After development, the temporary well will be allowed rest for approximately 20 minutes prior to sample collection. Following purging, Hull will collect groundwater samples that will be pumped through the Waterra or bladder pump tubing at a flow rate of less than 100 ml/min. pamples will be transferred directly into laboratory - preserved sample containers and placed on ice in a cooler. Following collection of each sample, Hull will retrieve and decontaminate the Waterra foot -valve pump by washing it with Alconox and water and rinsing it with deionized water. In addition, the sample tubing will be replaced between each sampling interval. The groundwater sample in the upper portions of the aquifer (i.e., shallow and intermediate, as appropriate) will be collected by withdrawing the screen to the appropriate depth and purging and collecting a groundwater sample as described above. The process for purging and collecting the relatively shallower groundwater sample will then be completed as