Assessing heavy metal contamination in agricultural soils: a new GIS-based Probabilistic Pollution Index (PPI) - case study: Guarda Region, Portugal. - Silvia Aparisi-Navarro; Maria Moncho-Santonja; Beatriz Defez; Carla Candeias; Fernando Rocha; Guillermo Peris-Fajarnés (Ann. GIS, 2025)