Trends of polycyclic aromatic hydrocarbon levels and mutagenicity in Santiago's inhalable airborne particles in the period 1992-1996.

Trends of polycyclic aromatic hydrocarbons (PAHs) for 1992-1996 (cold season) and their mutagenic activity were investigated in organic extracts from the Santiago, Chile, inhalable particles (PM(10)). The highest PAH concentrations were observed in 1992 and declined dramatically in the following years. During this period, total PAHs decreased 85%, carcinogenic PAHs 82%, and benzo[a]pyrene, the most potent carcinogen, 85%. In spite of this significant decrease, PAH levels in respirable particles were higher than those reported in recent studies in Australia, Europe, and the United States. PAH profiles were analyzed by principal component (PC) analysis and Pearson correlation analysis. PC1 represents 71% of the variance, suggesting that most PAHs might originate predominantly from one main generic source. Higher correlations were obtained for the major carcinogenic PAHs. Most of the samples assayed were highly mutagenic to Salmonella typhimurium both in the presence and in the absence of metabolic activation system (S9), especially in the coarse fraction, but direct mutagenicity did not decline significantly. Incubation of calf thymus DNA with organic extracts from particulate matter and xanthine oxidase allowed the detection of five nitro-PAH-DNA adducts. Thus, nitroarenes might play an important role in the mutagenic activity of inhalable particles in Santiago, representing a high risk for human health.