Entre a contaminação e a escassez hídrica: uma análise dos riscos associados à qualidade da água do Riacho Agon, Catolé do Rocha - PB

Abstract

The analysis of water contamination resulting from changes in land use and land cover is crucial for assessing environmental impacts and the risks associated with water quality. Thus, the present study aims to investigate water conditions through correlations between environmental constraints, land use and land cover, and water quality in the Agon stream microbasin. To this end, land use and land cover mapping of the area of interest was performed using data from the MapBiomas project, alongside water sampling (surface and groundwater) for the analysis of physical, chemical, and microbiological parameters. To understand the degree of aquifer vulnerability in the Agon stream microbasin, the GOD method (Groundwater occurrence, Overall lithology, and Depth to water table) was employed. The generated data allowed for an integrated analysis of the parameters established by the Ministry of Health (Ordinance 888/2021) and the CONAMA Resolutions (No. 357/2005 and No. 396/2008). The relevance of this study is justified by the microbasin’s location in the Brazilian Semi-arid region, a region characterized by a negative water balance, which reinforces the importance of conserving existing water resources. Additionally, there is a scarcity of research focused on understanding how water contamination in the local context can increase water scarcity in the region. Therefore, there is a need for detailed analyses regarding contamination and water scarcity, as water pollution represents a serious risk to public health and ecological balance. The juxtaposition of environmental characteristics — an unconfined alluvial aquifer embedded in crystalline geology, under a semi-arid climate with fluctuations in annual and interannual rainfall patterns, intermittent flow, and intense land use and cover — combined with high aquifer vulnerability (GOD index of 0.56), resulted in a critical situation in the Agon stream microbasin. The results revealed that the water is unfit for consumption at all sampling points due to microbiological contamination, high nitrate levels, and other physical-chemical alterations (turbidity and Total Dissolved Solids - TDS). This reality found in the Agon microbasin is dialectically contradictory: it is an area that, while facing socioeconomic and environmental difficulties related to water scarcity, is simultaneously submerged in a logic of significant contamination