Environmental impacts management of grain and sweet maize through life cycle assessment in Sao Paulo, Brazil

Maize is the second most produced food commodity in the world. Brazil is the world's third largest producer of maize, and the state of Sao Paulo is one of the major maize producers in Brazil. This study uses life cycle assessment to quantify and compare the environmental impacts to produce one ton of grain and sweet maize in the southwest of Sao Paulo state, from cradle-to-storage at seaport boundaries. The life cycle inventory was elaborated for the 2016-2017 harvest season. Environmental impacts were assessed using the CML 2015 impact assessment method. Three other methods were tested in sensitivity analysis. Results showed impacts of 203 kg CO2 eq. for global warming, 0.55 kg SO2 eq. for acidification, 0.53 kg PO4 eq. for eutrophication, 1197 MJ for abiotic depletion, and 962 kg DCB eq. for freshwater ecotoxicity, per ton of grain maize. A comparison of grain with sweet maize showed that the latter had lower environmental impacts if consumed at Sao Paulo megacity. Improvements are necessary for the systems and can be achieved by minimizing or substituting the most impactful flows (i.e., hotspots), which were fertilizers (for global warming and eutrophication), pesticides (for freshwater ecotoxicity), and transport activities (for abiotic depletion and acidification). Sensitivity analysis showed that a reduction of 20% in the transport process affected most the results. Transport activities can thus be an important opportunity to improve the environmental impacts of these systems and are also an incentive for producers to explore local market.