Avaliação dos impactos ambientais no lixão a céu aberto no município de Apuí, Amazonas

Abstract

Improper disposal of municipal solid waste (MSW) constitutes an environmental challenge in Amazonian municipalities, particularly in areas with limited sanitation infrastructure. In the municipality of Apuí, Amazonas State, Brazil, the continued use of an open dumpsite represents an environmental liability with the potential to affect soil, water resources, and local environmental conditions. In this context, this study aimed to assess the environmental impacts associated with the Apuí open dumpsite through the integrated application of the Landfill Quality Index (LQI) and the Water Quality Index (WQI). This applied research adopted a qualitative and quantitative approach with descriptive and exploratory characteristics. The study comprised a bibliographic and documentary review, assessment of the locational, structural, and operational conditions of the disposal site using the CETESB-adapted LQI, and monitoring of the water quality of the Juma River during the dry (October 2025) and rainy (March 2026) periods. Physical, chemical, and microbiological parameters were analyzed and, when applicable, compared with the standards established by CONAMA Resolution No. 357/2005 for Class 2 freshwaters. The LQI score was 2.1, classifying the disposal site as inadequate and revealing structural, operational, and environmental protection deficiencies, including the absence of soil lining, leachate drainage and treatment systems, and adequate operational control. Water quality assessment showed BOD₅,₂₀ concentrations above the reference standard at P1 and P3 during the dry period, while phosphate concentrations were higher during this period and were used only as a complementary parameter. During the rainy period, a pH of 5.7 was recorded at P1, below the minimum limit established for Class 2 freshwaters. The WQI, calculated for the rainy period, was 59 at P1, upstream, and 58 at P4, downstream, classifying water quality as Good at both sampling points. The absence of total nitrogen and total phosphorus data during the dry-period campaign prevented calculation of the WQI for this period. The identification of fish farming and cattle ranching activities upstream indicated the presence of additional potential sources of nutrients, organic matter, and microorganisms within the watershed. It is concluded that the integrated application of the LQI and WQI enabled the characterization of both the disposal site's conditions and water quality in the monitored river reaches, revealing inadequate waste disposal conditions and localized changes in water quality parameters. However, the presence of multiple potential sources and the limitations of the sampling design preclude attributing the observed changes exclusively to the dumpsite, reinforcing the need for systematic environmental monitoring and measures aimed at site closure and environmental recovery.