Optimal farm size reduces global poverty-induced soil antibiotic exposure risk

Farming activities contribute to soil antibiotic pollution, posing health risks for rural farm workers, especially on small farms in impoverished regions. The effectiveness of large farms in reducing poverty-induced soil antibiotic exposure risk (SABER) remains uncertain. Here we integrate global datasets on concentration of soil antibiotics, rural farm-worker employments and on-farm working hours to quantify SABER. We find that exposure-weighted relative populations are concentrated in underdeveloped regions, particularly East Africa and South and Southeast Asia. A 1,000 ha farm is optimal for SABER reduction, farm employment and working hours, outperforming both smaller and larger farms. Establishing large farms in the top 20% of priority areas can cover 47.3-75.5% of SABER hotspots, while establishing large farms in the top 44% of priority areas achieves the highest coverage of SABER hotspots without substantial declines in rural employment. This approach offers practical strategies to mitigate SABER while maintaining rural farm-worker employment.