title: Bioassay-directed identification of toxic organic compounds in creosote-contaminated groundwater.
abstract: Despite the fact that creosote mainly consists of polycyclic aromatic hydrocarbons (PAHs), more polar compounds like phenolics, benzenes and N-, S-, O-heterocyclics dominate the groundwater downstream from creosote-contaminated sites. In this study, bioassay-directed fractionation, combined with fullscan GC-MS, identified organic toxicants in creosote-contaminated groundwater. An organic extract of creosote-contaminated groundwater was fractionated on a polar silica column using high performance liquid chromatography (HPLC), and the toxicity of the fractions was measured by the Microtox-bioassay. PAHs, which comprise up to 85% of pure creosote, accounted for only about 13% of total toxicity in the creosote-contaminated groundwater, while methylated benzenes, phenolics and N-heterocyclics accounted for ca. 80% of the measured toxicity. The fraction containing alkylated quinolines was the most toxic single fraction, accounting for 26% of the total measured toxicity. The results imply that focus on PAHs may underestimate risks associated with creosote-contaminated groundwater, and that environmental risk assessment should focus to a higher degree on substituted PAHs and phenolics because they are more toxic than the unsubstituted ones. Additionally, benzenes and N-heterocyclics (e.g., alkylated quinolines) should be assessed.
authors.affiliation: Bioforsk - Norwegian Institute for Agricultural and Environmental Research, Frederik A. Dahls Vei 20, Norway. thomas.hartnik@bioforsk.no
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartnik
authors.forename: Hans Ragnar
authors.initials: HR
authors.lastname: Norli
authors.forename: Trine
authors.initials: T
authors.lastname: Eggen
authors.forename: Gijsbert D
authors.initials: GD
authors.lastname: Breedveld
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003407:Creosote / Q000737:chemistry* / Q000633:toxicity; D004784:Environmental Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity
chemical_list: D009930:Organic Chemicals; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D003407:Creosote