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Seminarios académicos y conferencias

Rodrigo Soares, Columbia-SIPA

"Impacts of Glyphosate Use in Agriculture on Birth Outcomes of Surrounding Populations"

Coautores: Mateus Dias y Rudi Rocha,

16 Mayo 2018 - 15:30 hrs.

Sala de postgrados, Facultad de Ciencias Económicas y Administrativas UC

Abstract: This project assesses the impact of glyphosate use on the health of human populations in surrounding areas. Glyphosate is the most used herbicide in the world. There is a lot of controversy on its potential effects on human health, but no robust evidence, particularly on externalities at levels commonly used in agriculture. Our empirical strategy relies on the fact that glyphosate is strongly complementary to the use of genetically modified seeds in soybean production. We start by building an instrument for the adoption of genetically modified seeds based on the suitability of different soils and climatic characteristics. This instrument arguably solves the problem of endogeneity of glyphosate use, but still leaves open the possibility that soybean adoption may affect health through other channels apart from glyphosate use (such as, for example, increased income from expansion in agricultural production). We deal with this second concern by looking at externalities across municipalities that are part of the same water basin and, therefore, share the same water resources. In short, the empirical strategy measures exposure to glyphosate through its use in nearby municipalities sharing the same water resources, and, in addition, instruments this use by the suitability of these nearby municipalities to the new seeds. We detect negative and statistically significant effects of glyphosate use on birth outcomes. We also conduct various robustness exercises: (i) outcomes in a given municipality are only affected by the use of glyphosate upstream from it, not downstream; (ii) effects are stronger in periods and areas subject to more erosion, when it is more likely that water bodies would be contaminated by glyphosate; and (iii) the timing of the effect matches the timing of expansion in the use of genetically modified soybeans in Brazil. Our results indicate externality effects of glyphosate use on populations considerably distant from the original locations of use, but receiving water from these locations. As we understand, nothing similar has been documented before in the literature.