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Ms. Debra Bloom Page 2 December 29, 2009 It is the MPCA VIC program staff opinion that additional investigation is necessary to determine if impacted perched groundwater is migrating onto the Site from the adjoining PIK parcel and impacting the soil and groundwater at the Site. Additional information is needed in the development of the RAP/CCP to describe the proposed roadway development plans in more detail and to develop contingencies and response actions to the soil and groundwater contamination that is potentially present. Specifically, the MPCA requests the following additional investigation requirements: • Advance several additional borings on the north side of the roadway and to the south of borings P-53 and P-28, to the east of the former Indianhead Warehouse building; • Advance one or two borings on the north end of Prior Avenue, to the north of the roundabout; • Advance one or two borings in the roadway at the south end of the former PIK maintenance building located near Author Avenue; • Collect and analyze several soil samples from each boring, and analyze the samples for volatile organic compounds (VOCs). One sample shall be collected near the surface, where soils are proposed to be excavated for the roadway and a deeper sample shall be collected near the depths that the utilities will be excavated; • In the area of the former PIK maintenance building analyze samples for VOCs, polynuclear aromatic hydrocarbons, 8 RCRA metals, and diesel range organics; and • Collect a perched groundwater sample from each of the borings and analyze the samples for VOCs. The MPCA also requests the following modifications to the RAP/CCP: • Provide information in the RAP describing the anticipated depths that will be excavated for the roadway and utility installation. Cross-sections would be helpful to determine if the depths excavated for the utilities will encounter contaminated soil or groundwater; • Provide information on the clean-up goals for the project. Discuss in regards to the Soil Reterence Values (SRVs) and the Soil Leaching Values (SLVs); • Discuss the criteria for determining if soil can be reused on the Site with regards to the SRVs and SLVs; • Provide an estimate of the amount of impacted soil that will be encountered and require disposal; • Taking into account the additional groundwater investigation required above, provide information on how perched groundwater will be prevented from impacting and migrating through the utility trenches; and provide more detailed information on the treatment, sampling, and disposal of impacted perched groundwater.