Indicadores da qualidade de solo nas margens do Rio Meia Ponte, estado de Goiás : fatores determinantes para monitoramento ambiental

Abstract

The discharge of domestic and industrial effluents into water bodies compromises the quality of water for the public supply of municipalities and for the maintenance of living beings in natural environments, both aquatic and terrestrial. The Sewage Treatment Plants (STPs) are institutions responsible for performing these procedures; however, the load of organic matter discharged into urban rivers after treatment can still compromise the quality of water and soil in subsequent stretches, leading to a compromise of the entire basin. The objective of this research is to associate enzymatic toxicological and geoprocessing soil quality indicators along the Meia Ponte River, a water body that flows through the municipalities of Itauçu, Brazabrantes, Goiânia, Pontalina and Cachoeira Dourada, to identify contamination by effluents. Soil samples were collected at a depth of 0-20 cm, during the rainy and dry periods, at six points along the Meia Ponte watercourse (at the limits of five municipalities in the state of Goiás). pH, moisture content, as well as the activity of the enzymes β-glycosidase, acid phosphatase and arylsulfatase were evaluated. The ecotoxicity of the soil was also evaluated by the variation of the luminescence of the bacterium Vibrio fischeri. Data were analyzed using Two-way ANOVA and Hotelling's T2 test, considering p<0.05. We used the databases available on the portals of the State System of Geoinformation of Goiás and MapBiomas project, to make maps of the study area and land use. The enzyme activity showed no significant variation, considering points before and after the discharge of effluents, as well as the climatic period of collection. As for the evaluation of land use and occupation, it was found that from 1985 onwards the Meia Ponte watershed underwent profound changes in its conversion. Thus, the toxicity test revealed a high level of environmental degradation, especially in points of agriculture, both family farming and high productivity, highlighting the need for continuous evaluation of these areas and the use of bioindicator tools for soil quality.