GIS-Based PFAS Risk Evaluation Toolkit
Weston & Sampson assisted the Connecticut Department of Energy and Environmental Protection (CTDEEP) in developing a comprehensive GIS-based toolkit to evaluate relative PFAS release risks across the state. The toolkit was designed as a web app hosted in the CTDEEP’s ArcGIS Online organization. The application consolidated data from multiple authoritative publicly available from federal, state and local feature service sources. Additional proprietary data was published to the organization for private consumption as well. Source data included the following:
- NAICS Codes with PFAS potentially utilized
- Public water supply
- Fire department locations
- Fire training areas
- Airports
- EPA superfund sites
- RCRA generators
- Sewage treatment plants
- CTDEEP PFAS specific/suspected hazardous waste sites
Vital layers regarding sensitive receptors, hydrogeologic, soil, and surface water travel paths and wellhead protection included the following:
- Wetlands
- Aquifer protection areas
- Water bodies
- Critical habitats
- USGS soils
- Surficial stratified drift
- Ground contours
- Roads
- Parcel boundaries
- Watershed boundaries
The toolkit included a project-specific query tool that allows for screening of potential risks to a sensitive receptor using multiple database layer inputs. This allowed CTDEEP to prioritize sampling of water supplies based on the greatest risk of PFAS contamination by reporting the greatest number of NAICS users within every source protection area in the state. Further refinement of the query can be performed by adding in parameters such as presence of gravel soils beneath a potential source, distance from the supply well, and topography. CTDEEP has utilized the toolkit to assist in locating potential sources of PFAS when routine sampling has identified PFAS impacts, selecting key locations to perform assessment of surface water and fish tissue impacts, and determining which publicly owned treatment works may be receiving PFAS discharges.