Genotoxicity of fractionated organic material in airborne particles from Sao Paulo, Brazil

Particulate matter less than 10 mu m aerodynamic diameter (PM10) is associa ted with adverse health effects including increased respiratory problems an d mortality. PMIO is also associated with increases in cancer in some urban areas. Identification of toxic compounds in PM10 is a step toward estimati ng exposure to these compounds and evaluating their public health risk. How ever, the toxic compounds on PM10 are part of a highly complex mixture of c ompounds that makes chemical characterization difficult. Before this study, there has been little investigation of genotoxic compounds in particulate matter from Latin American cities. Here, both bioassay (mutagenicity) and c hemical analyses were conducted with organic solvent extracts of PM10 colle cted from Sao Paulo, a major Brazilian city. Sequential extraction in dichl oromethane (DCM) followed by acetone (ACE) yielded 20.3% and 10.2% of the t otal mass, respectively. Non-polar and moderately polar organic material so lubilized in DCM. ACE extracted more polar organic species and some inorgan ic ions. Both extracts were fractionated separately using cyanopropyl-bonde d silica chromatography with organic solvents of increasing polarity. The m ass distribution among the fractions was measured. The mutagenic activity o f the fractions was assayed using the microsuspension procedure with the Sa lmonella typhimurium tester strain TA98, with and without addition of metab olic enzymes (S9). The DCM extract had about four times higher mutagenic ac tivity than the ACE extract. In general, addition of S9 resulted in an incr ease in mutagenicity of DCM fractions, but a decrease for the ACE extract. Most of the activity was concentrated in fractions in the mid-range of pola rity within both the DCM and ACE extracts. The fractions were analyzed by g as chromatography with mass selective detection (GC/MS) without derivatizat ion. The most mutagenic fractions in the DCM extract contained ketones, ald ehydes, and quinolines. The most mutagenic ACE fraction had ketones, carbox ylic acids, and aldehydes. (C) 1999 Elsevier Science B.V. All rights reserv ed.