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 identify the principal mutagenic compounds in an organic solvent extract of coal-tar-contaminated sediment from Sydney Harbor, Nova Scotia. Biological 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 higher molecular mass polycyclic aromatic hydrocarbons (PAHs). A normal phase high-performance liquid chromatography (HPLC) technique was developed to separate the PAH-rich solvent extracts into fractions containing isomeric PAHs of a single benzologue class. These fractions were analyzed by probe mass spectrometry and gas chromatography-mass spectrometry (GC-MS), and subjected to biological assays using strain YG1025 with the addition of oxidative metabolism (4% and 10% S9). Fractions containing compounds of molecular weights 252, 276, 278, and 302 amu exhibited mutagenic activities of 930 ± 125, 510 ± 100, 250 ± 40, and 370 ± 140 rev/mg sediment, respectively. The molecular weight 252 and 276 amu fractions were further analyzed using reversed-phase HPLC and GC-MS to identify the individual PAHs responsible for the observed biological activity. High molecular mass PAHs including benzo[a]pyrene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and compounds of molecular weight 302 amu were found to be responsible for the majority of the mutagenic activity displayed by this complex environmental mixture