INVESTIGATION OF THE MICRONUCLEI FREQUENCY IN WISTAR RATS EXPOSED TO WATER THAT SUPPLIES ARARAS CITY (SP) = INVESTIGA O DA FREQUêNCIA DE MICRONúCLEOS EM RATOS WISTAR EXPOSTOS á áGUA QUE ABASTECE O MUNICíPIO DE ARARAS (SP)

The industrial modernization and the increase of the use of chemical products had led to the pollution of the environment for diverse toxic residues, compromising the life quality of the alive organisms. Mutagenicity and genotoxicity studies are important to detect them and to evaluate the exposition risks. The micronucleus’ test is used in the detention of clastogenic and aneugenic agents, recommended internationally for evaluation of the mutagenic potential of diverse products. Being thus, this work had been for objective to analyze the genotoxic potential of effluent in the water that supplies the Araras city by means of the micronucleus technique. Four groups of male Wistar rats treated by gavage with drinking waters (negative control group), with a knowledge toxic substance (positive control group) and with water of the areas had been used (test groups). The tested water was collected at 2005 october, and 2007 april, in two different points, in the confluence between the Furnas Stream and the Araras Stream, also in the Hermínio Ometto embankment. Bone narrow samples of rats have been obtained after 15 days of treatment, they were stained with Giemsa-Wright and analyzed for optic microscopy in immersion. It has been evaluated the frequency of micronucleated polychromatic erythrocytes (MPEs) in 2.000 polychromatic erythrocytes for each animal. It was applied statistics analysis by ANOVA, that demonstrated not to have significant difference in the frequency of micronuclei found between the test group and the negative control group, in both studied areas, suggesting that, in the conditions where the experiments had been carried the analyzed water seems do not present genotoxic potential and probably don’t cause risks to human heath. = A moderniza o industrial e o aumento do emprego de produtos químicos levaram à polui o do ambiente por resíduos tóxicos, comprometendo a qualidade de vida dos organismos vivos. Estudos de mutagenicidade e genotoxidade s o importantes para detectá-los e avaliar seus efeitos, e o teste do micronúcleo é recomendado nesse caso. Sendo assim, este trabalho teve por objetivo analisar o potencial mutagênico de efluentes presentes na água que abastece a popula o de Araras, por meio da técnica do micronúcleo. Foram utilizados quatro grupos de ratos Wistar, machos, tratados por gavage. O grupo controle negativo que recebeu apenas água, o grupo controle positivo que, além da gavage com água, recebeu, 24 h antes do sacrifício, uma dose de meta-metil-sulfonato (MMS) e os grupos testes que receberam água dos pontos de coleta, realiza