Mutagenicity of polycyclic aromatic hydrocarbon fractions extracted from urban air particulates

Polycyclic aromatic hydrocarbon (PAH) fractions, purified from extracts of airborne particles collected in the area of Genoa municipality, were assayed for mutagenicity in the Salmonella/microsome test. PAH fractions accounted for only a portion of the total mutagenic activity and also displayed a different specificity of genetic activity, as compared to unfractionated material. The analysis of 224 samples collected from January 1986 to November 1987 in 10 different localities led to a large number of positive results in strain TA100 with S9 mix and, less frequently, also in TA98 without metabolic activation. Mutagenicity was related to the intensity of anthropogenic atmospheric pollution, and showed some seasonal variations, although it was not possible to discriminate particular sources of pollution on the basis of mutagenicity patterns. The mutagenic potency in TA100 (S9+) of airborne PAH fractions was significantly correlated with the concentration of individual PAHs in most of the monitored localities. The spectrum of mutagenicity of monthly samples pooled from several localities in S. typhimurium strains, with and without S9 mix, provided evidence for some contribution of nitro derivatives of PAHs or possibly also of other compounds present in the same fractions. The results obtained are discussed in view of their predictive value as indicators of potential health hazards, and of the reliability of this biological tool as a complement to chemical analyses in the evaluation of ambient air pollution.