Avaliação do estado trófico e qualidade das águas de dois açudes no município de Cruz das Almas, Ba

Abstract

Freshwater is a resource that has a inestimable importance for human development and the knowledge about water quality in a determined region constitutes a fundamental key for the environmental conservation and public health maintenance. In this way, this study has as objective to assess the trophic state and the quality of water in two dams located in Cruz das Almas, a region in the Reconcavo of Bahia. It was realized in six spots over a period of ten months of data collection and water for further analysis, with goals of study the limnological variables, nutrients and determine the trophic state of the environment. It was found values out of the recommended limit to the variables conductivity, dissolved oxygen and total phosphorus. Although this statistical analysis it was possible verifying a significative variation (p>0,05) between the dams when we talk about temperature, pH, conductivity, dissolved oxygen, coliform bacteria and total phosphorus. Spots 1, 2 and 6 were classified as hypereutrophic, spots 3 and 5 were supereutrophic and spot 4 was classified as eutrophic by the Trophic State Index (TSI), considering the variables chlorophyll-a and total phosphorus. Probably the trophic state was determined by diffuse contributions from the surroundings. The analyzes of coliform bacteria didn't demonstrate biological contamination in the environments that were studied. In this way, complementary studies are recommended applying the Water Quality Index (WQI) and more samples to carry out microbiological analyzes, in order to evaluate in a more consistent and comprehensive manner the quality of the reservoirs and the possible uses of these areas for the population, as well as the influence of these environments on other sources that may be receiving their contributions.