Environmental Pollution in the Alto Atoyac Basin, Mexico: A Systematic, Spatial, and Temporal Review of Contaminants and Monitoring Efforts

The Alto Atoyac Basin (AAB) in central Mexico is one of the most environmentally degraded regions in the country. This review systematically compiles 60 peer-reviewed studies on environmental contamination from 1975 to 2024. A unified, standardized database supported spatial and temporal analyses using GIS and non-parametric tests, revealing pollution hotspots and disparities in monitoring coverage. Spatial analysis showed a high concentration of studies along the Atoyac River, while nineteen municipalities lacked any records. Research primarily focused on surface water and sediments, with limited attention given to groundwater, soils, air, and food matrices. Data on human exposure remains scarce and fragmented, limiting risk assessment. The evidence reveals widespread contamination linked to industrial, urban, and agricultural pressures. Detected pollutants include pathogens, heavy metals, and diverse organic compounds exceeding national and international thresholds. Spatial analysis highlights pollutant concentrations in densely populated and industrialized zones, while temporal patterns show ongoing degradation from continuous discharges and limited remediation efforts. The findings emphasize long-term ecological degradation and potential health risks, underscoring the need for integrated monitoring and spatially informed management to guide recovery and policy actions. Future efforts should focus on continuous monitoring, multivariate and spatial modeling, and integrated basin-management frameworks to support restoration in the AAB.