title: Impacts of structural photomodification on the toxicity of environmental contaminants: anthracene photooxidation products.
abstract: The toxicity of polycyclic aromatic hydrocarbons (PHAs) is known to be enhanced by light via photosensitization reactions (production of active oxygen) and photomodification of the chemicals (e.g., oxidation) to more toxic compounds. Anthracene (ANT) toxicity in particular has been found to increase dramatically following photomodification. The objective of this study was to identify the photooxidation products of ANT and assess the toxicity of selected photoproducts. High performance liquid chromatography (HPLC) analysis of anthracene photooxidation revealed a complex array of oxidation products; prevalent among these were anthraquinone (ATQ) and hydroxy-anthraquinones (hATQs). Eleven of these compounds were tested for toxicity using growth inhibition of the duckweed Lemna gibba L. G-3. All but one of the compounds tested were found to be toxic, and when UV radiation was present in the light source toxicity was generally enhanced. The chemicals were also irradiated under SSR prior to toxicity testing. In about half the cases, the ATQ compounds were rapidly photooxidized and the resultant photoproducts were more toxic than the parent compounds. Interestingly, 2-hydroxyanthraquinone, which was not subject to photooxidation, was the most toxic of the compounds tested. As a light stable compound it presents the risk of a persistent environmental hazard.
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Mallakin
authors.forename: B J
authors.initials: BJ
authors.lastname: McConkey
authors.forename: G
authors.initials: G
authors.lastname: Miao
authors.forename: B
authors.initials: B
authors.lastname: McKibben
authors.forename: V
authors.initials: V
authors.lastname: Snieckus
authors.forename: D G
authors.initials: DG
authors.lastname: Dixon
authors.forename: B M
authors.initials: BM
authors.lastname: Greenberg
mesh_terms: D000873:Anthracenes / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects* / Q000633:toxicity*; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000378:metabolism / Q000528:radiation effects* / Q000633:toxicity*; D019684:Magnoliopsida / Q000187:drug effects / Q000254:growth & development; D010083:Oxidants, Photochemical; D010788:Photosynthesis; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D013329:Structure-Activity Relationship; D013472:Sunlight; D018675:Toxicity Tests
chemical_list: D000873:Anthracenes; D004785:Environmental Pollutants; D010083:Oxidants, Photochemical; C034020:anthracene