DETERMINATION AND GENOTOXICITY OF HIGH-MOLECULAR-MASS POLYCYCLIC AROMATIC-HYDROCARBONS ISOLATED FROM COAL-TAR-CONTAMINATED SEDIMENT

A bioassay-directed chemical fractionation methodology was used to ide ntify the principal mutagenic compounds in an organic solvent extract of coal-tar-contaminated sediment from Sydney Harbour, Nova Scotia. Bi ological assays with Salmonella typhimurium bacteria with the addition of oxidative metabolism indicated that the majority of the mutagenic activity observed in the sediment extract was associated with the high er molecular mass polycyclic aromatic hydrocarbons (PAHs). A normal ph ase high-performance liquid chromatography (HPLC) technique was develo ped to separate the PAH-rich solvent extracts into fractions containin g isomeric PAHs of a single benzologue class. These fractions were ana lyzed by probe mass spectrometry and gas chromatography-mass spectrome try (GC-MS), and subjected to biological assays using strain YG1025 wi th the addition of oxidative metabolism (4% and 10% S9). Fractions con taining compounds of molecular weights 252, 276, 278, and 302 amu exhi bited mutagenic activities of 930 +/- 125, 510 +/- 100, 250 +/- 40, an d 370 +/- 140 rev/mg sediment, respectively. The molecular weight 252 and 276 amu fractions were further analyzed using reversed-phase HPLC and CC-MS to identify the individual PAHs responsible for the observed biological activity. High molecular mass PAHs including benzo[a]pyren e, benzo [ghi] perylene, indeno[1,2,3-cd] pyrene, and compounds of mol ecular weight 302 amu were found to be responsible for the majority of the mutagenic activity displayed by this complex environmental mixtur e.