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Ms. Ann Kolata April 4, 2011 SB1067.400.0001 Page 2 Petrie to survey and stake the locations of the prior or known existing impact locations. The staked locations will serve as the primary basis for locating the installed sampling points; final locations will be subject to relocation in the field as discussed above. Following staking of these points, the Indiana Utility Plant Protection Service (IUPPS) one -call number will be contacted to mark the location of known utilities in the vicinity of the proposed sampling locations. In general, our proposed approach entails defining the horizontal and vertical extent of various chemicals of concern (COCs) in the vicinity of prior or known existing areas of environmental impacts to soil and /or groundwater at the Site. COCs to be investigated include volatile organic compounds (VOCs), semi - volatile organic compounds (SVOCs), U.S. EPA Resource Conservation and Recovery Act (RCRA) metals (both total and dissolved), and polychlorinated biphenyls (PCBs). Not all COCs will be analyzed for at each sampling location, and the sampling scheme is based on the history of use or current or prior presence of these COCs at each location. 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 a deeper depth of approximately 45 to 49 feet bgs at each of thirteen (13) locations. At approximately eight (8) additional locations, temporary screens will be advanced to the shallow and intermediate depths only. As stated above, the locations may be adjusted slightly in the field based on field observations such as utility locations, etc. If necessary, 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. Drill cuttings and sample purge and decontamination water will be containerized and placed on -Site 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 deeper depth (i.e., between approximately 45 and 49 feet bgs), at which point the outer casing of the sampling system will be withdrawn to expose a four foot long stainless steel wire wrapped screen.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 sampled. In addition, Hull's representative 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. Samples 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 samples in the shallow and intermediate portions of the aquifer 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 shallow