The Illinois State Geological Survey (ISGS) currently has a cooperative agreement with the Illinois Department of Transportation (IDOT) to perform preliminary environmental site assessments (PESAs) for selected road construction projects in Illinois. The ISGS performs an average of 100 PESAs per year ranging in size from a single parcel or intersection to 70-mile long corridors targeted for future highway development. One time-consuming aspect of conducting a PESA is the investigative effort required to accurately map the location of sites of potential environmental concern. The use of GIS data has greatly reduced the time needed for these investigations; however, no GIS coverage of USEPA Superfund sites in the state of Illinois is currently available with the spatial accuracy required to effectively aid in a PESA investigation. With assistance from the USEPA and the Illinois EPA, the ISGS is currently undertaking an effort to produce such a GIS coverage.

The initial stage of coverage development utilizes a database of Superfund sites supplied by the USEPA. These records are cross-referenced with in-house records and Illinois EPA files to map the boundaries of each site. The mapped extent of each site feature is dependent on available information and is based on USEPA or IEPA site maps or on a search of municipal records to determine property boundaries. The resulting coverage is being constructed using ArcView 3.2 and will also be linked to a database of site attributes.

The mapping is taking place county by county, beginning with Chicago-area counties, since a large portion of the PESA work for the state is conducted in that area. The development will progress through the other metropolitan areas of the state, culminating with the rural counties. The maps will be shared with IDOT, USEPA, and IEPA.