VARIABILIDADE SAZONAL DA QUALIDADE DE ÁGUA EM LAGOAS URBANAS NO NORDESTE DO BRASIL

The Pituacu, Abaete, Tororo and Paixao lagoons, in the city of Salvador-BA (Brazil) have in common the insertion of a lentic ecosystem in the urban environment of a developing city. This research describes the pattern of seasonal variation of non-conservative and biological physical-chemical parameters during the years 2017 and 2018 in 16 points spatially distributed in the four lagoons during the rainy season (from April to July) and dry season (August to November). Water quality was determined in accordance with the Water Quality Index (WQI) and application of the Trophic State Index (TSI), in addition to the CONAMA ordinancy 357/2005. The results showed that the four monitored lagoons exhibit some parameters outside the conformities established by CONAMA ordinances, in addition they are strongly eutrophic, but in a contrasting way, with good quality ratings considering their use, with the exception of Lagoa de Pituacu. It is concluded that systematic assessments should be considered more frequently with the aim of collecting greater and more accurate information on the quality conditions of these ecosystems, and studying their quality changes as a reflection of the urban condition on their conservation.