Variação temporo-espacial da qualidade da água na Laguna do Roteiro - Alagoas, nos anos de 2005 a 2017

Abstract

The present study aimed to evaluate the temporal-spatial variation of water quality indicator parameters in the Lagoon of Roteiro, located between the municipalities of Barra de São Miguel and Roteiro, in the state of Alagoas, Brazil. The parameters were obtained through three water sampling campaigns in Laguna do Roteiro, on August 5, 2005, October 11, 2005 and May 9, 2017. The general objective of this work is to evaluate the temporal and spatial variation of the water quality indicator parameters in Laguna do Roteiro in the years 2005 and 2017. The specific objectives are: (a) to determine the variation of dissolved inorganic nutrients (nitrite, ammonia, nitrate and total phosphorus), (b) to determine the variation of chlorophyll ‘a’, (c) to evaluate the variability of the eutrophication index and (d) to compare results with Conama Resolution 357 of March 17, 2005. When we compare the Laguna do Roteiro with the other lagoons mentioned in this work, it is observed that the degree of eutrophication varies between supereutrophic and hypereutrophic, a process caused by the launch, “in natura” of residential sewers and fertilizers used in the plantation of sugar cane, in addition, the anthropogenic influence has caused changes in its physical-chemical parameters of the Laguna do Roteiro.