Eletrorresistividade e química para fins ambientais em áreas de disposição de resíduos sólidos nas porções norte e centro-sul do estado de Roraima

Abstract

The improper disposal of solid waste is a predicament that has been escalating over the centuries, despite the existence of more sustainable modalities, open-air landfills are still predominantly utilized. In this manner, the objective of this research is to diagnose leachate contamination originating from the so-called Municipalities of the State of Roraima – ADMRS through geophysical and chemical methods for environmental purposes in the northern and central-southern regions of the state of Roraima. The investigation of this possible contamination employed both direct methods (geoelectric) and indirect investigation methods (physicochemical), utilizing the electrical resistivity test (indirect method) and physicochemical analyses of pH, grain size analysis, and moisture content (direct method), thus providing, a plausible perspective on the potential contamination of these areas in the subsurface and surface, respectively. Thus, three the three ADMRs studied herein (Amajari, Mucajaí, and Iracema) were categorized as open-air landfills. Concerning the geoelectric and physicochemical context of the Amajari ADMRS, values below 167 Ωm at surface depths of up to 1.3 m were the resistivity values most closely associated with a potential contamination zone in the area; it was observed that, from east to west, the contamination plume extended along the 10 m depth, with the soil exhibiting acidic characteristics, which under the prevailing conditions, could worsen further due to the constant decomposition of solid waste, considering the geological aspects of the area. For the Mucajaí ADMRS, the electrical and physicochemical conjecture revealed the formation of a vertical contamination plume to the west of the ADMRS area, spanning depths from 1 to 24 meters. There was a generalization of low resistivity, around 64 Ωm, in the Mucajaí ADMRS, and physicochemical analyses yielded results similar to those of Amajari, with moisture content exceeding 10% and pH values above 7. There is a possibility of contamination reaching the water bodies in the area, such as the Traíra and Azul streams, which surround the ADMRS. Lastly, the electroresistive and physicochemical behavior of the former Iracema ADMRS indicated a minimum resistivity value of around 15 Ωm, making it possible to delineate the contamination plume with a spread extending to nearly 4 m in depth in the eastern range, whose chemical analysis in the area revealed pH values lower than 4, considered highly acidic, which could exacerbate the ongoing decomposition of the residue, even though the ADMRS is no longer active. Therefore, the obtained results demonstrated how effective the combination of geophysical studies with chemistry is for waste disposal areas., emphasizing the importance of environmental studies and compliance with prevailing legislation for the management and administration of solid waste. This approach serves to prevent and mitigate environmental impacts.