MUTAGENICITY OF AIRBORNE PARTICULATE ORGANIC MATERIAL FROM URBAN AND INDUSTRIAL-AREAS OF SAO-PAULO, BRAZIL

The mutagenicity of airborne particulate matter at three different sit es within the Sao Paulo urban area and the Cubatao industrial area, Sa o Paulo State, Brazil, was evaluated using the Salmonella mutagenicity assay over a pear's period (June 1990-May 1991). Total suspended part icles (TSP) were collected using a Hi-vol sampler and extracted with m ethylene chloride by ultrasonication. Pooled seasonal extracts were te sted using S. typhimurium TA98 and TA100 with and without metabolic ac tivation (S9) and TA98NR and TA98/1,8-DNP6 without metabolic activatio n. Organic extracts of the samples with the highest monthly TSP concen tration were also assayed for mutagenicity. All samples collected at S ao Paulo and Cubatao showed mutagenicity with strain TA98, and in gene ral the addition of S9 did not modify the mutagenic response, suggesti ng the prevalence of direct-acting frameshift mutagens in the atmosphe re of these sites. The mutagenicity detected in the urban areas of Sao Paulo (mainly downtown) was much higher than in the Cubatao industria l area and similar to the more urbanized cities in the world, where ve hicle emissions are the major pollution source. Results obtained with the strains TA98NR and TA98/1,8-DNP6 suggested the presence of mononit ro- and dinitroarenes contributed to the mutagenicity of these atmosph eric samples. A seasonal variation was observed with higher levels of frameshift mutagens during Spring in Sao Paulo and Summer in Cubatao. During the Winter, more significant responses were found with strain T A100 in the presence of S9 at all sites. Monthly samples presented hig h levels of mutagenicity during the period of June to November. Result s from this research provide support for Air Pollution Control Program s in the detection of the more potent organic mutagenic compounds in t he atmosphere and may help in the establishment of priorities for cont rol and regulatory actions.