Biomonitoramento em áreas poluídas e não poluídas do Rio Uberabinha, região de Uberlândia Minas Gerais, por meio de análise de micronúcleos e freqüência de cromossomos B em bagre (Rhamdia quelen)

Abstract

CHAPTER 2: The aquatic environment is contaminated by toxic chemicals from industrial, agricultural and domestic activities. The environmental toxicology characterizes the effects related by chemical substances present in some species and their biological implications. The genus Rhamdia presents B chromosomes, which appear to be conserved in most species of the genus, and represents character important to the evolutionary process. The study aimed to evaluate the cytogenetic aspects of 45 copies of a population of Rhamdia quelen collected in three areas with different standards of water quality in Uberabinha River, the region of Uberlandia, Minas Gerais. The species were evaluated by the Micronucleus Test, by counting the erythrocytes. The TMN results indicate the significant genotoxic and cytotoxic potential in the points, in agreement with chemical analysis. This way the species Rhamdia quelen can be considered an efficient bioindicator. The chromosome counting showed the modal number 2n=58 with variance between none and one to seven B chromosomes. The higher frequence of B chromosomes and presence of the karyotype with seven chromosomes supernumerary occurred at Point 3, referring to the Local with the highest potentially mutagenic. There was positive correlation between the presence of B chromosomes and the interference on Environmental quality.