HUMAN CELL MUTAGENICITY OF OXYGENATED, NITRATED AND UNSUBSTITUTED POLYCYCLIC AROMATIC-HYDROCARBONS ASSOCIATED WITH URBAN AEROSOLS

Polycyclic aromatic compounds (PAC) are ubiquitous pollutants in urban air that may pose risks to human health. In order to better assess th e health risks associated with this class of compounds, a total of 67 PAC that either have been identified (55) or are suspected to be prese nt (12) in urban aerosol samples were tested for mutagenicity in a for ward mutation assay based on human B-lymphoblastoid cells. The cell li ne used (designated hlAlv2) constitutively expresses the cytochrome P3 501Al, which is known to be necessary for the metabolism of many promu tagens. The PAC tested included 39 polycyclic aromatic hydrocarbons (P AH), 19 oxygen-containing PAH (oxy-PAH) and nine NO2-substituted PAH ( nitro-PAH). A total of 26 PAH were mutagenic. In comparing the minimum mutagenic concentrations of the mutagenic PAH with that of benzo[a]py rene (B[a]P) it was found that dibenzo[a,l]pyrene (DB[al]P), cyclopent a[c,d]pyrene (CPP), naphtho[2.1-a]pyrene, dibenzo[a.e]pyrene (DB[ae]P) and 1-methylbenzo[a]pyrene were 24 +/- 21, 6.9 +/- 4.2, 3.2 +/- 3.0, 2.9 +/- 7.9 and 1.6 +/- 1.4, times, respectively, more mutagenic than B[a]P, and that dibenzo[a,k]fluoranthene and B[a]P were approximately equally mutagenic. The 19 other mutagenic PAH were between similar to 2 and similar to 1800 times less mutagenic than B[a]P. OF the oxy-PAH tested only phenalenone. 7H-benz[d,e]anthracen-7-one, 3-nitro-6H-diben zo[b,d]pyran-6-one, cyclopenta[c,d]pyren-3(4H)-one, 6H-benzo[c,d]pyren -6-one (BPK) and anthanthrenequinone were mutagenic: however, with the exception of BPK, these were over 50 times less active than B[a]P. BP K was similar to 3 times less active than B[a]P. Seven of the nitro-PA H were mutagenic including 9-nitroanthracene 1-nitropyrene, 2-nitroflu oranthene, 3-nitrufluoranthene, 1,3-dinitropyrene, 1,6-dinitropyrene ( 1.6-DNP) and 1,8-dinitropyrene. 1.6-DNP was similar to 4 times less ac tive than B[a]P; the six other mutagenic nitro-PAH were between 20 and 380 times less active than B[a]P. These results are discussed in term s of their relevance for determining the most important mutagens in am bient air. Based on reported concentrations of PAC in ambient aerosols , it is possible that CPP. DB[ae]P. DB[al]P and BPK could account for a greater proportion of the mutagenicity than B[a]P in some aerosols.