2026/01/01 by Nonito Ros-Berja, Elisa García-Gómez, Lúcia H.M.L.M. Santos +3 · 2 voices
Earth and Planetary Sciences · Environmental Science · #Groundwater and Isotope Geochemistry #Pesticide and Herbicide Environmental Studies #Pharmaceutical and Antibiotic Environmental Impacts
paper · doi:10.1016/j.wroa.2026.100509
openalex publication_date 2026/01/01 · openalex created_date 2026/02/11 · openalex updated_date 2026/08/01
Droughts are projected to become more frequent and severe, threatening groundwater resources in Mediterranean regions by altering water quality and hydrological dynamics. This study provides for the first time a field-scale assessment of 85 emerging contaminants (ECs), including 41 pharmaceuticals (PhACs), 10 metabolites and transformation products, and 34 endocrine disrupting compounds (EDCs) plus caffeine as stimulant, under drought conditions in the Onyar River Basin, a representative Mediterranean catchment. Results showed that prolonged drought disrupted stream–aquifer interactions, increasing aquifer vulnerability to multiple pollution sources. The most widely detected PhACs were carbamazepine (0.8–4 ng/L), and sulfamethoxazole (0.6–20 ng/L), while dominant EDCs, were tolyltriazole (3.9–239.54 ng/L) and tris(2-chloroethyl) phosphate (TCEP; 3.3–260 ng/L), and caffeine (6.5–154 ng/L). Concentrations were generally highest in wells near the Onyar River, reflecting river–aquifer interactions, whereas agricultural activities using livestock waste as fertilizer contributed mostly to sulfonamide inputs. During a prolonged drought (2020–2024) the stream-aquifer relationship changed its dynamics, modifying groundwater flow and contaminant transport pathways, increasing aquifer vulnerability to diffuse pollution sources. Indicators, as the Groundwater Ubiquity Score (GUS) and the Persistent-Mobile-Toxic (PMT) classification are valuable tools for predicting contaminant behavior, especially when estimated site-specific sorption parameters are used. Both support groundwater management in Mediterranean catchments, where drought conditions influence the occurrence, spatial distribution and fate of ECs, complicating predictions of contaminant transport and aquifer protection. Therefore, this study underscores that the occurrence of ECs must be interpreted in the context of hydrological conditions prevailing at sampling.