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<br /> <br /> <br />Field Investigation Report <br />Old Snelling Avenue and County Road E Improvements <br />WSB Project No. R-015447-000 Page 8 <br /> <br /> <br />4. Discussions and Conclusions <br /> <br />This Field Investigation was conducted to evaluate current subsurface soil, groundwater, and soil vapor <br />conditions for the proposed Old Snelling Avenue and CR E Improvements project in Arden Hills, <br />Minnesota. An analytical exceedance map is included as Figure 3. The following discussion and <br />conclusion information is provided: <br /> <br />· PAH- and DRO-impacted soil above MPCA reuse criteria was identified at borings EB-3 and EB- <br />8. Benzo(a)pyrene was detected in soil samples EB-3 (8-10), EB-8 (2-4), and EB-8 (8-10) above <br />the Tier II Industrial SRV. BaP Equivalent concentrations were detected above the Tier I <br />Residential SRV in sample EB-3 (8-10) and above the Tier II Industrial SRV in samples EB-8 (2- <br />4) and EB-8 (8-10). DRO exceeded MPCA criteria for unregulated fill in samples EB-3 (8-10), <br />EB-8 (2-4), and EB-8 (8-10). Offsite disposal of excavated regulated fill at an MPCA-permitted <br />landfill will be required during reconstruction. <br /> <br />· 1,3-Butadiene was detected in both soil vapor samples above the Residential 33X ISV. 1,3- <br />Butadiene is often found in urban environments due to its association with petroleum products, <br />vehicle exhaust, and asphalt. It is unlikely that 1,3-butadiene stems from a release of hazardous <br />substances at the Project Corridor. <br /> <br />· No evidence of contamination was identified in the groundwater samples collected from borings <br />EB-1, EB-8, and EB-12. No compounds exceeded regulatory criteria and no odors or sheen were <br />noted in the field during collection of the groundwater samples. <br />