Environ Monit Assess. 2026 Jul 29;198(8):891. doi: 10.1007/s10661-026-15708-0.
ABSTRACT
The expansion and intensification of agriculture in the Argentine Pampas have increased pesticide use, raising concerns about groundwater contamination in aquifers used for drinking water. In this context, contamination risk assessment is a key tool for environmental management, although results may vary depending on the methodology applied. This study compares two approaches for assessing pesticide-related groundwater contamination risk in the Quequén Grande River watershed (Argentina). Risk was defined as the interaction between aquifer contamination hazard and population vulnerability. Hazard was estimated by combining aquifer vulnerability (DRASTIC-P) with two representations of contaminant load: (i) a land-use-based approach derived from LANDSAT imagery, and (ii) an empirical model based on pesticide leaching experiments relating mobility to soil organic matter. Social vulnerability was assessed using a census-based index. All analyses were conducted within a GIS framework. Results show that the two approaches produce markedly different spatial risk patterns. These differences were evaluated through methodological comparison and preliminary field evidence, but not through a comprehensive independent basin-wide validation. The land-use-based method identified a larger proportion of high-risk areas (20.1%), whereas the laboratory-based approach yielded more restrictive estimates (9.4%) and greater spatial differentiation. These differences reflect the conceptual assumptions underlying each method. The results highlight that method selection strongly influences risk assessment outcomes and should be aligned with management objectives, data availability, and acceptable levels of uncertainty.
PMID:42525282 | DOI:10.1007/s10661-026-15708-0
