Temporal behavior analysis of leachate contamination in a tropical landfill

Leachate generation is one of the problems present in the landfills and dumps, needing monitoring and quantification for the environmental conservation. The objective of this paper is to evaluate temporal data of leachate contamination in a municipal solid waste (MSW) landfill, located in the midwest of São Paulo state, Brazil. The physical-chemical parameters and chemical compounds of the local groundwater were evaluated during 13 years (2002 to 2015). The methodology included data processing and temporal behavior analysis by Mann-Kendall test. Physical-chemical parameters demonstrated a change from acid to basic medium and decrease of BOD, COD, and TOC concentrations. Chemical compounds demonstrated high concentrations close to the administration building of the landfill, despite the decrease of certain compounds (Al, Fe, Hg, K, Na, Pb, SO₄^2-, total PO₄^3-, Zn) over time in the entire landfill area. The results demonstrate that the landfill is in natural attenuation process, and the structures of the surrounding landscape and the location of the MSW disposal are fundamental to understand the presence and rate of each chemical compound.