R2017-143 Authorizing Amendment to Agreement between the City of Decatur and MDA Properties LLC

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Bo&: = 558 Page: 497 September 30, 2015 Mr.Billy Tyus Focused Phase II ESA- 151 West Main Street/152 West Wood Street Page 4 No observable physical evidence of potential contamination in the form of petroleum hydrocarbon or solvent-like odors or staining was encountered in the extracted soil cores at SBI, SB7 or SBB. PID readings were 0.0 ppm for these soil samples. The remainder of the soil samples had visual, olefactory, and/or PID responses indicating possible contamination. Soil Boring Logs are included as Attachment 3 and describe the specific geological conditions encountered at each soil boring location. The soil samples were collected and analyzed for volatile organic compounds (VOCs), semi- volatile organic compounds(SVOCs),and polychlorinated biphenyl(PCB)constituents present in the Illinois Environmental Protection Agency's(TEPA)Target Compound List (TCL), as set forth in 35 IAC 740 Appendix A.The(EPA's TCL is a series of constituents that are most likely to be present on sites contaminated by typical commercial and industrial land uses.Analysis of Resource Conservation and Recovery Act (RCRA)8 metals and soil pH was also completed to evaluate the leaching potential of inorganic and ionizing organic constituents for the Soil Component of the Groundwater (SCGW) Ingestion Route. Upon completion, all bore holes were plugged with 3/8 inch bentonite chips in accordance with general practice. Boring holes completed through impervious surface materials were patched at the surface with like materials. Groundwater Investigation Temporary groundwater monitoring wells TW1-TW3 were constructed by inserting 10-foot sections of 1-inch diameter schedule 40 polyvinyl chloride(PVC)riser and well screen(0.010" wide slots spaced 0.125"apart)threaded with 10-15 feet of 1-inch diameter schedule 40 PVC riser with o-ring seal piping, into the 2-inch diameter borehole at soil boring locations 561, 566, and SB9 upon completion of soil sampling activities. All screen and riser piping had threaded connections and the annular space between the borehole and well piping was packed with clean 10/20-sized silica sand blend from total depth to grade. Hydrated bentonite was utilized at the surface to create a temporary seal. On September 18, 2015, Fehr Graham collected groundwater samples from temporary groundwater monitoring wells TW1-TW3. Prior to sample collection, the wells were developed in accordance with Fehr Graham's SOPS as presented in the City's USEPA-approved QAPP using a peristaltic pump and disposable polyethylene tubing. All groundwater samples were analyzed for target compound list for (TCL)VOCs, SVOCs, PCBs, and RCRA 8 metals. Groundwater pH was collected in the field at each temporary well location. After sampling the temporary groundwater monitoring wells, the well screens and riser piping were removed and the boreholes were properly abandoned as previously described. Regional groundwater flow direction is expected to be moving southwesterly towards Lake Decatur. Regulatory Standards To assess potential environmental impacts,the 35 IAC Part 742 TACO,Tier 1 SROs for commercial and industrial land uses,GROs for Class 1 Groundwater; and GROs for the Indoor Inhalation Exposure Route(Diffusion and Advection)were used as guidelines for qualifying concerns associated with potentially contaminated soil,soft gas, and groundwater. TACO is the IEPA's approved risk-based method for developing remediation objectives for the assessment