Journal of the Association of Environmental and Resource Economists · 2026 · Tzu-Hui J. Chen
Abstract
This study investigates the impact of glyphosate, the most widely used herbicide, on birth outcomes in the US Corn Belt. Using water flow mechanisms to identify causal effects, the study shows that glyphosate affects populations far from application sites through waterborne transmission. The results suggest that a 10 kg/km² increase in upstream glyphosate use led to a 4.6% rise in neonatal deaths in lower-income areas, with no observed effects in higher-income regions. The research design also incorporates variations in spatial distances, seasonal exposure patterns, and rainfall data to ensure that the observed health impacts are attributable to glyphosate. Evidence suggests that avoidance behaviors and water treatment are potential mechanisms of the heterogeneous effects.