About 18,000 metric tons of municipal solid waste, or about half of what São Paulo State discards every day, is deposited in landfills located in areas that are environmentally highly susceptible. These data are from the study performed by researchers from the National Institute for Space Research (INPE) in São José dos Campos in inland São Paulo State (Journal of Geographic Information System, February 21, 2017). They divided the state into five environmental vulnerability categories (very high, high, medium, low and very low) based on 15 different indicators, such as distance from geological faults, soil infiltration rates and distance from rivers and lakes. Next, they georeferenced 420 areas where municipal solid waste is deposited: 89 sanitary landfills, where the soil must be made impermeable before waste is deposited there; and 331 controlled landfills, where waste is deposited directly on the land, usually in ditches. The survey indicated that 82% of the land in São Paulo is ranked as very low, low or medium environmental risk. “However, in the remaining 18%, classified as areas with high or very high susceptibility, it was found that 46% of all waste generated in the state is deposited in 85 landfills,” explains geographer Victor Fernandez Nascimento, the first author of the study, who focused his PhD studies at INPE on this topic. The most vulnerable landfills are located on the outskirts of the metropolitan regions of São Paulo, Santos, Vale do Paraíba and Campinas.
