Bioassay-directed identification of toxic organic compounds in creosote-contaminated groundwater

• Published in: Chemosphere (Oxford) 2007, Vol.66 (3), p.435-443
• Main Authors: Hartnik, Thomas, Norli, Hans Ragnar, Eggen, Trine, Breedveld, Gijsbert D.
• Format: Article
• Language: English
• Subjects: alkylated quinolines; Animal, plant and microbial ecology; Applied ecology; aromatic compounds; Bioassay-directed fractionation; bioassays; Biological and medical sciences; bioluminescence; Bioluminescence inhibition; Chromatography, High Pressure Liquid; Creosote; Creosote - chemistry; Creosote - toxicity; Ecotoxicology, biological effects of pollution; Environmental Monitoring - methods; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; General aspects; Groundwater; groundwater contamination; heterocyclic nitrogen compounds; Microtox bioassay; N-heterocyclics; Organic Chemicals - analysis; Organic Chemicals - chemistry; Organic Chemicals - toxicity; phenolic compounds; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - chemistry; Polycyclic Aromatic Hydrocarbons - toxicity; quinolines; toxicity testing; Toxicity Tests; Vibrio fischeri; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2006.06.031

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.