title: Photo-induced toxicity and oxidative stress responses in Tigriopus japonicus exposed to nitro-polycyclic aromatic hydrocarbons and artificial light.
abstract: Photo-induced toxicity is an important phenomenon in ecotoxicology because sunlight reaches many organisms in their natural habitats. To elucidate whether sunlight enhances the toxicity of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), the acute toxicities of 10 nitro-PAHs and the related compound 1-nitropyrene (1-NP) to Tigriopus japonicus were assessed in darkness or under light conditions. In addition, the relationships among the toxicity of 1-NP to T. japonicus, lighting condition, and the concentration of reactive oxygen species (ROS) formed were investigated in the presence or absence of the ROS scavenger ascorbic acid in the test solutions. Light irradiation increased the toxicity of all tested nitro-PAHs except 1,5-dinitronaphthalene. Among the compounds tested, 1-NP was the most phototoxic: it was more than 1000 times more toxic under the light conditions than in darkness. In contrast, at the same light levels, pyrene was not phototoxic. Light irradiation induced the generation of ROS in the 1-NP exposure groups, and the immobilization rate of T. japonicus increased with the amount of ROS produced. The addition of ascorbic acid to the test solutions suppressed both the generation of ROS and the light-induced immobilization of T. japonicus. To accurately assess the ecotoxicologic risk of nitro-PAHs, their overall photo-induced toxicity must be considered.
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan. Electronic address: onduka@affrc.go.jp.
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Onduka
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ojima
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Ito
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Mochida
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
authors.forename: Mana
authors.initials: M
authors.lastname: Ito
authors.affiliation: Education and Research Center for Marine Resources and Environment, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Koyama
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Fujii
mesh_terms: D000818:Animals; D033342:Copepoda / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D008401:Gas Chromatography-Mass Spectrometry; D008027:Light; D009574:Nitro Compounds / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000633:toxicity*; D011721:Pyrenes / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D009574:Nitro Compounds; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C032668:1-nitropyrene
keywords: 1-nitropyrene; Ascorbic acid; Photo-induced toxicity; Photodegradation products