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A preliminary environmental site assessment along the alignment of I-74 and its bridge over the Mississippi River was completed by the Illinois State Geological Survey for the Illinois Department of Transportation in 2002. The purpose of the survey was to determine the presence of any environmental concerns, both natural and man-made, that the Illinois DOT might encounter during activities to build a new bridge to carry I-74 over the Mississippi River between Moline, IL, and Bettendorf and Davenport, IA. A preliminary investigation of the project area from 27th Street in Moline to 67th Street in Davenport, using government databases, Sanborn Fire Insurance Maps, city directories, and a drive-through of the project area, identified a total of 127 sites that were believed to constitute a possible risk to the project. Following reduction of the project to just the Illinois side of the river, further investigation was conducted of 37 sites in Moline. The location of the project in part of downtown Moline and long-time development along the Moline riverfront by industrial and commercial operations offered a variety of parcels for investigation, ranging from corner gasoline stations to railroads and foundry sites. The dominant sites comprised current or former underground storage tank and leaking underground storage tank sites, automotive repair sites, and foundries and other sites where metals were handled. Railroads, junk yards, cleaners, and spills made up the remainder of the sites investigated. During a limited subsurface investigation, heavy metals and volatile organic compounds indicative of petroleum were detected at several sites. Examples of some of these sites will be presented.

A Targeted Brownfields Assessment of a former power plant was conducted using the Triad approach, through the efforts of EPA Region I and Metcalf & Eddy, the Brownfields Technology Support Center, and the town of Greenwich, Connecticut. The Triad approach is an integrated strategy for managing decision uncertainty at hazardous waste sites that is being promoted by EPA, along with other Federal agencies. The Triad approach consists of three elements: systematic project planning, real-time measurement technologies, and dynamic work strategies (). The Triad approach recognizes that overall decision uncertainty is generally governed more by sampling uncertainty (that is, the uncertainty that the samples collected adequately represent site contamination), than by analytical uncertainty (that is, the accuracy and precision of the analytical method) (Crumbling , 2001). The town plans to redevelop the nine-acre site as a waterfront park, and needed to decide whether this plan was feasible, and if so, what remedial measures might be necessary before the park could be constructed. Because coal ash was historically disposed at the site, it was considered probable that site surface soil throughout the entire nine acres would show concentrations of contaminants that exceed Connecticut residential direct exposure criteria. Historical information also suggested the possibility of localized petroleum and polychlorinated biphenyl (PCB) releases. The goal of the investigation was to obtain sufficient data, in one mobilization, to determine the nature and extent of surface soil contamination. Attaining this goal was judged to be infeasible using a traditional approach of soil sampling with analyses in off-site laboratories, and evaluation of results several weeks later. The Triad approach, with its focus on development of a conceptual site model, evaluation of decision uncertainty, use of field/real-time analytical methods, and field decision-making, was selected over a traditional approach. Field analytical techniques included siteLAB® test kits for total petroleum hydrocarbons (TPH) and total polyaromatic hydrocarbons (PAHs), EPA’s X-ray fluorescence instrument for metals, and the EPA mobile laboratory for PCBs. Soil samples were also analyzed by an off-site laboratory for arsenic with 48-hour turnaround. Sampling locations were added based on feedback from the field analyses. The use of field methods allowed for sampling using a random-grid approach, with many more locations sampled than would have been possible by relying solely on the more costly off-site laboratory analyses. The team located an area of PCB contamination that might have gone undiscovered if a random grid sampling approach had not been used. A correlation was develop edbetween the TPH/PAH test-kit results and off-site laboratory results, which enabled use of the test-kit results to define the extent of soil contamination with TPH and PAHs. The results showed that site surface soil contains concentrations of arsenic, TPH, and PAHs at levels exceeding Connecticut residential direct exposure criteria. The observed concentrations are partially from the coal ash that is co-mingled with site soil. PCBs were also identified near an area where transformers had been located. The Triad approach yielded an estimated cost savings of approximately 35 percent, when compared with a traditional approach involving two mobilizations of 20 borings each, with locations selected judgmentally, and off-site laboratory analytical methods alone.

An investigation of groundwater-to-indoor air vapor intrusion of trichloroethylene (TCE) was conducted at a commercial building to 1) identify vapor pathways; 2) measure TCE attenuation; 3) evaluate whether building pressurization can reduce vapor intrusion; and, 4) evaluate seasonal effects on vapor intrusion. The investigation included a site assessment, both indoor and outdoor air sampling, and the modification of the existing heating, ventilation and air-conditioning system. The investigation found that preferential pathways, such as a floor crack, acted as conduits for vapor intrusion when the building was not properly ventilated. The investigation also found that air TCE concentrations were significantly attenuated between ground surface and the breathing zone and proper building pressurization can effectively minimize vapor intrusion. Weather conditions at the site did not significantly affect the indoor air TCE concentrations.