Avaliação da qualidade da água para uso da irrigação e dessedentação animal no perímetro irrigado de Sumé-PB.

Abstract

Water is a valuable resource that plays an essential role in the lives of living beings, especially in areas of the Brazilian semiarid zone (SAB), which face water scarcity and high evapotranspiration rates. In these areas, groundwater becomes an alternative for agricultural and livestock development. However, groundwater from unconfined aquifers is more subject to contamination due to urban development, where sewage, landfills and pesticides are sources of pollution. The objective of this study was to evaluate the quality of groundwater in wells located in the irrigated perimeter of Sumé-PB, for use of raw water in irrigation and animal watering. The study area is located in the alluvial region of the Sucurú River, irrigated perimeter of the municipality of Sumé, Paraíba, delimited by the geographic coordinates between latitude 7°28'00"S and 7°50'00"S, and between longitude 37°14'00"W and 36°49'00"W. Eight wells dug in the alluvial region of the Sucurú River were selected to collect water samples. The collections took place during the rainy and dry seasons, between 2023 and 2025, with 556 values of raw water quality indicators, obtained in situ using a Hanna HI9829 multiparametric probe, in addition to 420 laboratory analyses in triplicate, to determine the concentrations of Calcium (Ca2+) and Magnesium (Mg2+). The indicators evaluated were temperature, pH, electrical conductivity (EC), total dissolved solids (TSD), dissolved oxygen (DO), turbidity, calcium and magnesium, and the results obtained were compared with the recommendations made through CONAMA Resolution Nº. 396/2008, guidelines of the Food and Agriculture Organization of the United Nations (FAO) and international standards of South Africa, Canada and New Zealand. The results indicated significant seasonal variations, with worsening in the quality of raw water in the dry season, especially in wells P1 and P2, located near the urban area, which presented EC > 3,000 μS.cm-1 and STD > 2,000 mg.L-1, limiting its use for irrigation. Well P8 maintained ideal conditions of water quality (EC < 700 μS.cm-1; STD < 450 mg.L-1), while others require adapted management. The pH of the samples remained between 6.55 and 8.25, within the range recommended by FAO, suitable for water use to irrigation and animal watering. For use of water for animal watering, the water quality indicators obtained met the criteria for poultry, cattle, sheep and goats, except P1 and P2, during the dry season. It is concluded that the quality of the raw water was altered due to diffuse pollution, due to the discharge of untreated domestic sewage, in the urban area of the municipality of Sumé, PB, near wells P1 and P2, with the highest levels of impairment, suggesting strong anthropic interference. There was also a significant worsening of water quality indicators during the dry season, indicating seasonal influence on groundwater quality. It is recommended to plant salt-tolerant crops due to the quality of the water contained in the wells dug in the alluvium of the Sucurú River, popularly known as the “Amazonas well”, and continuous monitoring of these raw water quality indicators and expansion to identify microbiological indicators is recommended.