Geospatial analysis of trace metal pollution and ecological risks in river sediments from agrochemical sources in Morocco’s Sebou basin

Sediments in agricultural ecosystems serve as critical indicators of environmental pollution, particularly in regions subjected to intensive agricultural practices. This research evaluates the environmental hazards and implications of heavy metal (HM) contamination in river sediments from the Sidi Allal Tazi area within Morocco's Sebou basin. Twenty sediment samples were extracted from strategically designated locations, and the contamination levels were analyzed using a multi-index integration approach, multi-statistical analyses (MSA), and Geographic Information Systems (GIS). The results revealed considerable spatial variability in HM concentrations, with Cd and As displaying the highest contamination levels. Statistical analysis, incorporating Principal Component Analysis (PCA), identified anthropogenic activities as the primary contributors to contamination. Hierarchical Cluster Analysis (HCA) categorized metals based on common pollution pathways, while GIS mapping revealed the spatial distribution of contamination across vulnerable areas. Pollution indicators like the Geo-accumulation Index (I_geo) as well as the Pollution Load Index (PLI). revealed that 75% of sites were categorized under "very high pollution", emphasizing the severity of contamination. Contamination Factor (CF) classified 90% of Cd samples and 100% of As samples as "very high contamination". Risk indices indicated significant ecological threats, with Cd contributing to an RI exceeding 600 in many areas, signifying "very high risk". These findings highlight the urgent need for targeted mitigation strategies and sustainable agricultural practices. The integration of multi-index and GIS methodologies provides a comprehensive framework for assessing and managing sediment contamination, offering critical insights for policymakers and environmental managers.