Uso de indicadores microbiológicos na avaliação do grau de poluição em águas superficiais.

Abstract

The use of algae, fungi and bacteria (fecal coliforms, fecal streptococci and Pseudomonas aeruginosa) as indicators of the degree of organic pollution was analyzed in 4 aquatic bodies located in the Northeast of Brazil, in the State of Paraíba, which were classified as to their stage of trofia and saprobicidade. The research was carried out at points on the margin and at the center of three lentic aquatic bodies (Açude de Boqueirão, Açude de Bodocongó and Açude Velho), in the raw sewage and effluent from the E.T.E stabilization ponds of Campina Grande. Two points of the Bodocongó Creek were also analyzed at the confluence of this with the final effluent of E.T.E. The collections were carried out every two weeks, covering a period of 12 months, between October 1939 and September 1990, covering a hydrological cycle. Physicochemical parameters (DB0s, dissolved oxygen, pH, turbidity, transparency, temperature, nitrate, ammoniacal nitrogen and soluble orthophosphate) and microbiological parameters (fecal coliforms, fecal streptococci, Pseudomonas aeruginosa, chlorophyll a, identification of algae and The main groupings (formed by the largest number of points in each ecosystem and therefore representative of the same) and the average values ​​of the BODs allowed the classification of aquatic bodies in 4 levels of saprobicity, oligosaprobic (Açude de Boqueirão), (mesosaprobic (Açude de Bodocongó), a-mesosaprobic (Açude Velho) and polysaprobic (ETE and effluent stream) levels of fecal contamination increased from the Dligosaprobic ecosystem to the polysaprobic. the specifics of l g a s were characteristic for each aquatic body, according to their degree of pollution: diatoms in the Boqueirão Dam, the chlorophytes in the Bodocongó Dam, chlorophytes and cyanophytes in the Old Waters and green flagellates in the E.T.E and effluent stream. The frequency of isolation of filamentous fungi and white yeasts of the genus Candida was increasing following the increase of organic pollution, whereas rusty yeasts of the genus Rhodotorula and Sporobolomyces presented an inverse behavior. The trophic classifications of different authors, useful for temperate climates, were not adequate to fit the aquatic bodies studied, being more appropriate the saprobiological classification of SLADECEK (1979).