MEDIDAS DE FLUXO DE DIÓXIDO DE CARBONO E METANO EM UM DEPÓSITO DE RESÍDUOS INSALUBRE NA AMAZÔNIA

Dumps are important anthropogenic sources of greenhouse gas emissions into the atmosphere, mostly CH4. However, few studies on the subject have been carried out in the Amazon region. Several factors affect the production and emission of dumps gas. The objective of this study was to quantify the spatial variation of CO2 and CH4 production in an Amazon dump and try to associate the relative importance of some environmental factors with the fluxes. This study was carried out in an open-air dump in the metropolitan region of Belem, where approximately 11.0 million Mg of waste was deposited in 25 years, of which 6.4 million Mg was organic. The emission rates of CH4 and CO2 from the surface of the dump were determined using the closed dynamic flux chamber technique. The study was conducted in three cells of different ages, sampled in two moments between the Amazon rainy and dry season. The Aura dump has an area of 30 ha and emits a total of 51.49 Mg CO2 ha-1 month-1 and 3.16 Mg CH4 ha-1 month-1 to the atmosphere. This results in an expressive production of 1,359,961.04 Mg CO2-e year-1, being that 58.54% is due to CH4 flux. The spatial variability in CO2 and CH4 flux is very large, especially for CH4, forming hotspots of high concentrations, and perhaps because of this, the flow has not been correlated with micrometeorological variations.