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Ms. Ann Kolata October 17, 2011 S131066.400.0001 Page 3 Avenue and along Chapin Street at the locations shown on Figure 1). Soil borings associated with the proposed monitoring wells will be drilled using 4.25 -in., inside - diameter hollow -stem augers and continuously sampled using 24 -in. split -spoon samplers to the appropriate depth (i.e., either 30 feet bgs or 45 feet bgs). As with the direct -push sampling locations, the monitoring well locations may be modified based on field observations. Monitoring wells will be constructed of Schedule 40 PVC slotted screens and risers. Once the targeted depth has been reached, the well column will be slowly lowered to the base of the borehole. A clean silica quartz sand filter pack will be placed around the screen and will extend no more than two feet above the top of the screen. Sodium bentonite chips or pellets will then be placed on top of the sand pack. Above the chips or pellets, a thick bentonite slurry will be pumped into the annular space using a tremie pipe to a depth of approximately three feet below ground surface. The remaining three feet will be filled with concrete to anchor a flush -mount manhole. Monitoring wells will be developed following installation to remove fines that may have entered the well screen or filter pack during installation. Well development activities will continue until pH, temperature, and conductivity have stabilized for three consecutive well volumes, or until five well volumes have beer} removed, whichever is greater. Development waters will be collected and stored in a DOT approved 55- gallon drum. Following installation of the monitoring wells between CTW -3S /D and the Oliver Industrial Park, laboratory results from the temporary boreholes north and east of CTW -3S /D will have been received, and will determine whether additional downgradient temporary sampling point installation is necessary, or whether permanent monitoring wells may be installed in the vicinity of the previous temporary sampling points. This estimate provides a contingency for additional temporary sampling point installation should it be deemed necessary. Ultimately, permanent monitoring wells will be installed downgradient of CTW -3S /D as part of this scope of work; the costs for installation of all permanent well locations are included. We have included an additional mobilization and demobilization cost for the driller to install permanent wells in two stages should the second temporary sampling event be required. If this charge is not incurred, the Client will not be billed. Groundwater samples will be collected from all newly installed monitoring wells and submitted to the laboratory for VOC analysis using U.S. EPA Method 8260 and lead and arsenic analyses (because of historical detections of these metals in off -Site groundwater) in accordance with U.S. EPA Method 846 6010. Samples for lead and arsenic analyses will be submitted to the laboratory in both filtered and unfiltered form to allow for analysis of total and dissolved metals concentrations. Prior to sampling, the monitoring wells will be purged until pH, temperature, and conductivity measurements have stabilized, or until three well volumes have been removed, whichever is greater. Following purging, groundwater will be collected using low -flow methods and transferred to laboratory- preserved sample containers at rate of less than 100 ml /min and placed on ice in a cooler. Duplicate samples will be collected at randomly selected monitoring well locations. Field /equipment blanks will also be collected and submitted along with a trip blank for analysis as part of QA/QC of field procedures. Purge and decontamination waters will be collected and