Detection of the genotoxicity of air pollutants in and around the city of Sao Paulo (Brazil) with the Tradescantia-micronucleus (Trad-MCN) assay

Tradescantin pallida cv. /purpurea, a popular garden plant in Brazil, was u sed for the Tradescantia micronucleus (Trad-MCN) assay. In situ monitoring of the genotoxicity of air pollutants was carried out by sentinel approach, using the plant grown in the field or using the plants in pots which were carried to the monitoring sites. Two highly polluted sites, in Sao Paulo ci ty (Cerqueira Cesar and Congonhas) and two rural sites (the cities of Piras sununga, 200 km and Caucaia do Alto, 50 km from Sao Paulo, respectively) we re chosen for this study, in order to determine the gradient difference of the air pollution levels. Sentinel plants in Congonhas site presented the h ighest frequency of micronuclei (4.4%), in comparison with 2.2 and 2.3%, fo und in plants from Pirassununga and Cerqueira Cesar sites, respectively (Kr uskal-Wallis; P < 0.020). Significant increases (F test; P < 0.0001) in the frequency of micronuclei were observed in plants exposed in the polluted u rban sites (Cerqueira Cesar: 5.7%; Congonhas: 7.1% and Caucaia do Alto: 2.3 %). The increase in the frequency of micronuclei observed indicates the pot ential risk of mutagenicity in presence of high concentrations of pollutant s. (C) 2000 Elsevier Science B.V. All rights reserved.