Efeito de poluentes antropogênicos sobre a microbiota da Lagoa da Pajuçara, Maracanaú- CE

Abstract

The pressures of urbanization and industrialization around lagoons provide the increasing of several pollutants, making it one of the biggest environmental problems in the world. Thus, the objective of this work was to analyze the effect of the antopogenic actions on the microbiota of the Pajuçara Lagoon, Maracanaú. This spring was chosen because it is located in the Industrial District, and because it is a leisure alternative and a source of food for the population. For the accomplishment of this research two samplings were made, one in March and another in June. The water samples were collected at six points in the perimeter of the lagoon and using Escherichia coli as a microbiological parameter, the conditions of water use were evaluated according to Resolution 357 and 274, both resolutions of the National Environmental Council (CONAMA). Samples were inoculated into petri dishes containing separately culture medium supplemented with silver nitrate (AgNO3) and mercury (HgCl2) chloride for selection of heavy metal tolerant bacteria and non-selective culture medium for non-cultivable heterotrophic bacteria. Isolated strains were identified by means of morphotinorial characteristics and biochemical tests. According to the results obtained, the aquatic points pA1, pA2, pA3 and pA4 are unsuitable for primary contact activities, as well as the fishing practice. The highest values of E. coli found were in areas where there is greater contact of the population. The bacterial density of soil samples was more abundant in medium selective for silver resistant population than mercury. The BHC / NP and BHC / CM ratios were higher in the second collection, with P3 NP being the highest ratio. The identified strains had a predominance of gram positive rods, catalase positive and oxidase negative. The significant microbial growth reveals that in a total of cultivable heterotrophic bacteria a portion of these microorganisms are able to tolerate concentrations of silver and mercury.