Preliminary evaluation of cytotoxicity and genotoxicity, of water from the Tapanhon river basin (SP - Brazil) through Allium test (Allium cepa) [Avaliação preliminar da citotoxicidade e genotoxicidade, da água da bacia do rio Tapanhon (SP- Brasil) através do teste Allium (Allium cepa)]

Abstract

The present study aimed to verify the genotoxic and citotoxic potential in water samples from the basin of Tapanhon River, Pindamonhangaba, São Paulo, by using the Allium test. Water samples of the Tapanhon River and its affluents (the Primeira Água and Segunda Água Streams, the Galega Brook) as well as a sample from the Borba Spring have been collected for negative control. Six bulbs of Allium cepa have been submitted to each of the samples for 24 hours. The roots have been fixed in ethanol/acetic acid 3:1; they have also been submitted to the Feulgen reaction, and the meristematic portion has been crushed in slide for cellular analysis. As such, 6000 cells have been collected for evaluation of the mitotic index (MI) and micronuclei (MNC) as well as 300 cells in the metaphase and anaphase phases, to evaluate chromosome aberrations (CA). No MNC has been found in the samples tested. The MI values have shown to be elevated in all samples tested when compared to the control with statistical relevance, however, only for the samples from the Primeira Água Stream and the Galega Brook (p<0,05). Chromosome aberrations have been observed in all samples (p<0,05). These data suggest that along this bay there are substances which induce the citotoxic and genotoxic effects, which, in turn, have promoted alterations in the organism tested. © 2006 Sociedade Brasileira de Toxicologia.