Mutagenic potential of pollutans in the water of the Paraíba do Sul river, Tremembé, SP, Brazil, using the Allium cepa test

Abstract

The mutagenicity can be related to chromosomic breaks induced by environmental pollutants. The aim of this research was to characterize the mutagenic potential of the pollutants in the water of the Paraíba do Sul river, in Tremembé city, São Paulo State, Brazil, analyzing chromosomal changes in the meristematic cells of Allium cepa, in the summer (April) and winter (August) of 2008. The bulbs were exposed for 72 h to the treatments: water from river, Hoagland solution (negative control) and 15 µg/L from MMS – methyl methanesulfonate (positive control). In each treatment, three bulbs were exposed and for each bulb, five slides were prepared. For mitotic index (MI) and micronucleus (MN) frequency rate, a total of 2,000 cells per root/slide were analyzed and 100 cells for the chromosome aberrations (CA). In April, the pollutants induced a high mutagenic potential in the meristematic cells of Allium cepa, the frequency rate of MN, stickiness and CA from non-identified type were greater than the negative control. In August, the only significant change found was the chromosome bridges. There was no significant change for MI. These results indicate that the effluents which have varied sources are inducing harmful effects on the bioindicator, therefore, it is important to keep biomonitoring and adopting effluents control measures. The measures are important because these waters are used primarily for public supply and irrigation.

Keywords

• river pollution
• mutagenicity
• Allium cepa test
• chromosomes aberrations