In situ monitoring of the mutagenic effects of the gaseous emissions of a solid waste incinerator in metropolitan Sao Paulo, Brazil, using the Tradescantia stamen-hair assay

The present work was designed to determine the potential genotoxicity at th e vicinity of a solid waste incinerator in the metropolitan area of Sao Pau lo, using the Tradescantia stamen-hair bioassay. Experiments were carried o ut between December 1998 and April 1999 in four regions (40 pots of plants per site) selected on the basis of their pollution levels predicted by theo retical modeling of the dispersion of the incinerator's plume. The exposure sites were defined as follows: highest level (incinerator); a high level ( museum) located 1.5 km from the emission point; a moderate level (school, a t a distance of 3.5 km from the incinerator); and a control (at Jaguariuna countryside). The difference in genotoxicity among the groups was statistic ally significant (p < 0.001). The frequency of mutations observed in the co untryside was significantly lower [2.25 +/- 1.55, mean +/- SD (standard dev iation)] than that of the sites close to the incinerator. The frequency of mutations measured at the school (3.70 +/- 1.36) was significantly lower th an that measured at both the museum (4.89 +/- 1.12) and the incinerator (5. 69 +/- 1.34). In conclusion, we found a positive correlation between the sp atial distribution of the emissions of the incinerator located in an urban area and the mutagenic events measured by the Tradescantia stamen-hair assa y. The in situ approach employed in this study was simple, efficient, and o f low cost. No air or chemical extraction of pollutants was necessary for g enotoxicity testing as required by other assays.