SITE INFORMATION AND CORRESPONDENCE

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JUN/14/2006/WED 01:52 PM COS HSG & REDEV FAX No, 20993750qq F.007 Ms. Kitty Walker 6 7 June 2006 Direct Push Soil Sampling The Investigation Work Plan contains provisions to collect soil samples from 25 locations, as Attachment 8 shows, with eight locations planned for Project Area 4, eight locations planned for Project Area 3, and nine locations planned for Project Area 24. Stating, "The selection and rationale of the proposed sample locations in Parcel [Project Area] 3 is primarily to verify site conditions along the parcel boundaries." In addition, 13 locations will be used as sample locations for both soil samples and soil gas samples allowing for some level of correlation of data. The Investigation Work Plan provides for the collection of six soil samples at various depths at each location, and the selected analysis of the samples. An on-site laboratory will allow for the analysis of additional soil samples collected defining any discovered pollution. The Investigation Work Plan states, "SVOCs and PCBs initially will be analyzed from areas of historic commercial activities, with 25 percent of the samples collected outside this area for establishing background concentrations." The RDA allowed the clearing of the commercial buildings and the spreading of site soil and likely the import of some fill material. On-site samples do not represent historic background concentrations for the purpose of establishing cleanup goals. The RDA will need to submit a work plan proposing off-site sample locations to establish background for appropriate pollutants found on-site. HydropUnch Groundwater Samples The Investigation Work Plan contains provisions to collect grab groundwater samples. The Investigation Work Plan states, "The purpose for obtaining groundwater grab samples along the eastern and western boundaries is to evaluate whether impacted groundwater, if present, has migrated off-site. If impacted groundwater is identified, groundwater-monitoring wells may be installed.' The RDA is required to install four monitoring wells to monitor the pollution already found at the site, see our comment below. Also, there is a discrepancy as the figures and tables do not agree. The text of the work plan indicates that 15 grab groundwater samples will be collected, with three along Washington Street, while the referenced Table 4 shows 14 locations with no locations along Washington Street. Groundwater Monitoring Well Installation Construction The Investigation Work Plan states, "Should the results of the hydropunch sampling indicate that the groundwater beneath the site is impacted, additional shallow groundwater monitoring wells may be installed in Parcel 24, 3 and/or 4, at locations and depths based on the groundwater grab sample data." Again, it has already been demonstrated that soil and groundwater pollution exist in the preferential pathway that is the ballast and drainpipe beneath the railroad corridor. The 23 February 2006, Addendum to the Report of Findings of soil Excavation and Subsurface Soil and Groundwater Investigation, submitted by Wallace Kuhl & Associates Inc. on behalf of WorkNet, recommends the installation of three groundwater monitoring wells. Groundwater monitoring wells are necessary at the location of borings SB-5 and SB-7, see Attachment 3, and at least two other locations, to establish a groundwater gradient, and of course any other locations as determined by the investigation. Based on groundwater monitoring data from an adjacent cleanup site, the screened interval for the installed monitoring wells shall not exceed 10 feet.