Arsenic contamination in cereal crops poses significant risks to food safety and human health. We conducted a meta-analysis of 2,895 records from over 125,000 samples, including 2644 records from 736 publications (1979-2023) and 251 from the WHO GEMS Database, covering rice, wheat, and corn globally. Sample-size weighted analysis revealed a contamination hierarchy: rice (0.069 mg/kg) > wheat (0.064 mg/kg) > corn (0.044 mg/kg), with rice accumulation similar to 1.6-fold higher than corn due to anaerobic soil conditions facilitating arsenite mobilization. Irrigation water quality emerged as a dominant driver, with arid regions like Xinjiang, China showing 4-fold higher contamination than eastern provinces. Temporal analysis (1979-2023) revealed no significant trends (p > 0.05), indicating historical interventions have plateaued. Health risk assessment using the JECFA benchmark dose (BMDL0.(5) = 3.0 mu g kg(-1) d(-1)) identified critical disparities, with Margin of Exposure (MOE) spanning four orders of magnitude (0.50-12,327). Bangladesh adults exhibited MOE below 1.0 for wheat (MOE = 0.81), indicating intake exceeding safe thresholds. Children showed 2-3 times higher body-weight-adjusted exposure, with Kazakhstan children at highest rice-associated pediatric risk (MOE = 2.81). The Asia-Pacific region bears similar to 180 million of similar to 230 million at-risk individuals globally. Climate projections indicate potential 25% increases in rice arsenic bioavailability. Priorities include water-source interventions, pediatric-specific limits, and targeted monitoring in high-risk regions.