Environmental transformations of polycyclic aromatic hydrocarbons on glass surfaces

The authors investigated the environmental transformation of anthracene (A), 2-aminoanthracene (2-AA), benzo[a]pyrene (BaP), and 1-nitropyrene (NP) to understand the fate of PAH released to the atmosphere. Glass plates coated with 14C-labeled compounds were exposed continuously outdoors for periods ranging from 1 to 670 hr. Control plates were held in the dark. Breakdown products were separated from parent compound by high-performance liquid chromatography, quantified by liquid scintillation spectroscopy, and identified by standard spectroscopic techniques. Decomposition of A and 2-AA was almost total during 4-hr sunlight exposure. The NP decay rate could be fitted with a two-component exponential function; the half-lives of the rapid and slower components of breakdown were 14 and 533 hr, respectively. The BaP decay rate could be fitted with a single exponential function, with a half-life of 460 hr. 2-Nitrosoanthracene was tentatively identified as a decomposition product of 2-AA. The BaP was oxidized to phenol and quinone derivatives. Breakdown of NP involved loss of the nitro group and formation of a phenol, a dione, and a diol. Mutagenic activities of isolated NP breakdown products in Salmonella tester strain TA98 were significantly less than that of NP, probably reflecting loss of the nitro group. Studies are needed to determine if these results apply to particle-associated PAH