GIS-Based Regional Risk Assessment, A Source-Pathway-Receptor Framework for Diffuse and Point-Source Contamination

The new Soil Monitoring and Resilience Law introduces a harmonized, risk-based system for identifying contaminated soils, requiring regional screening to support stepwise investigation. To meet this need, two complementary regional risk-assessment methods were developed within the HEU ISLANDR project and applied in a European metropolitan area. Both use a Source-Pathway-Receptor logic, rely on geospatial datasets and were implemented in GIS through a documented, reproducible workflow. The first method targets diffuse contamination from agriculture, atmospheric deposition and urban emissions. Soil concentration data from European and regional monitoring are harmonized and compared with threshold values. Pathways are described using soil properties, hydrology, topography, land use and climate, while vulnerability analyses for human and environmental receptors support calculation of a regional diffuse-contamination index. The second method focuses on potentially contaminated sites linked to industrial or commercial activities. Sites are identified from historical records, land-use information and administrative sources, then evaluated through a structured hazard assessment combined with pathway relevance and receptor sensitivity to produce a prioritization index. Together, the two GIS-based methods provide a coherent framework for screening diffuse pollution patterns and site-specific risks, supporting proportionate decisions aligned with forthcoming legislation.