Impactos na qualidade da água e do solo no lixão encerrado do município de Nepomuceno - MG

Abstract

The final disposal of Municipal Solid Waste (MSW) in dump sites or controlled dumps has historically caused a range of environmental damage, including soil, water, and air contamination. This practice was also adopted in the municipality of Nepomuceno, where 9 hectares of land were used to dispose of MSW for 15 years. The aim of this study was to investigate the occurrence of soil, groundwater, and surface water contamination in the area of this closed dump site. For this study, groundwater samples were collected at four points located around the area, one located upstream from the hill and three downstream. The collections were carried out in triplicate in two campaigns, during the dry season and the rainy season. The data were analyzed using descriptive statistics, the Mann-Whitney test, and compared to relevant legislation. The soil analysis did not reveal any data above the recommended levels. However, the water analysis did reveal contamination of cadmium and lead in the monitoring wells during the dry season. No contamination was identified during the rainy season. High levels of BOD (2216,67 mg/l), COD (6095,00 mg/l), turbidity (14.080,00 UT), phosphorus (1,42 mg/l), total coliforms (984000,00 NMP/100ml) and thermotolerant (3540 NMP/100ml), were observed in the surface water. Nevertheless, there were issues with the construction of the monitoring wells P2 and P3, and the presence of animals may have affected the results surface water analyses. The Mann-Whitney test indicated a significant difference from the dry period to the rainy period in the variables BOD, COD for groundwater and turbidity only in the surface water. The contamination identified in the groundwater and surface water indicates the need for ongoing monitoring actions, including improvements to the structure of monitoring wells, additional points for surface water collection, and measures to mitigate the impacts of MSW disposal.