title: Evaluation of methods for predicting the toxicity of polycyclic aromatic hydrocarbon mixtures.
abstract: Risk assessments of polycyclic aromatic hydrocarbon mixtures are hindered by a lack of reliable information on the potency of both mixtures and their individual components. This paper examines methods for approximating the toxicity of polycyclic aromatic hydrocarbon (PAH) mixtures. PAHs were isolated from a coal tar and then separated by ring number using HPLC. Five fractions (A-E) were generated, each possessing a unique composition and expected potency. The toxicity of each fraction was measured in the Salmonella/mutagenicity assay and the Chick Embryo Screening Test (CHEST). Their abilities to induce ethoxyresorufin-O-deethylase and to inhibit gap junction intercellular communication in rat liver Clone 9 cells were also measured. In the Salmonella/mutagenicity assay, fractions were predicted to have potencies in the order C > D > E > B > A. Toxic equivalency factors (TEFs) for fractions A-E were in the order E > or = D > C > B > A. TEF values were 20,652, 20,929, 441, 306, and 74.1 micrograms of BaP equiv/g, respectively. A lack of agreement between assay-predicted potencies and chemical analysis-predicted potencies was observed with other assays and other methods of calculation. The results demonstrate the limitations of using a single method to predict the toxicity of a complex PAH mixture.
authors.affiliation: Department of Veterinary Anatomy and Public Health and Department of Civil Engineering, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: W R
authors.initials: WR
authors.lastname: Reeves
authors.forename: R
authors.initials: R
authors.lastname: Barhoumi
authors.forename: R C
authors.initials: RC
authors.lastname: Burghardt
authors.forename: S L
authors.initials: SL
authors.lastname: Lemke
authors.forename: K
authors.initials: K
authors.lastname: Mayura
authors.forename: T J
authors.initials: TJ
authors.lastname: McDonald
authors.forename: T D
authors.initials: TD
authors.lastname: Phillips
authors.forename: K C
authors.initials: KC
authors.lastname: Donnelly
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity; D002642:Chick Embryo; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D017629:Gap Junctions / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D008862:Microsomes, Liver / Q000378:metabolism; D009152:Mutagenicity Tests / Q000379:methods; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D051381:Rats; D015203:Reproducibility of Results; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics; D013329:Structure-Activity Relationship
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D001564:Benzo(a)pyrene; D019363:Cytochrome P-450 CYP1A1