Toxicity increases in ice containing monochlorophenols upon photolysis: environmental consequences.
The toxic effects of photoproducts formed upon the photolysis of 2- and 4-chlorophenol (CP) frozen solutions in polycrystalline ice phase were determined with a bacterial luminescence test (Vibrio fisheri), and in vitro biomarker assay for dioxin-like effects (inductions of AhR-dependent luciferase in H4IIE-luc cells) and compared to the toxic effects of products of the same photoreaction in aquatic phase. Coupling photoproducts formed in ice samples (3'-chlorobiphenyl-2,4'-diol and 3-chlorobiphenyl-2,2'-diol from 2-CP photolysis and 5-chlorobiphenyl-2,4'-diol from 4-CP photolysis) were found to be more toxic to V. fisheri than parent CPs and elicited significant inductions of dioxin-like effects (the effective concentrations EC50 approximately 3 x 10(-5) mol L(-1) corresponded to known weaker ligands of AhR, such as nonplanar polychlorinated biphenyls or polycyclic aromatic hydrocarbons). To complete the picture, a photoproduct formed from 4-CP (5-chlorobiphenyl-2,4'-diol) was synthesized, and a detailed toxicity assessment with purified compound confirmed the results obtained with irradiated samples. Our findings support a recently proposed model according to which solar radiation can trigger the formation of new types of organic pollutants in polar ice or tropospheric ice cloud particles, presenting possibly greater risk to the environment than the parent compounds.
Bláha
Ludek
L
RECETOX-Research Center for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 3, CZ-625 00 Brno, Czech Republic. ludek.blaha@recetox.muni.cz
Klánová
Jana
J
Klán
Petr
P
Janosek
Jaroslav
J
Skarek
Michal
M
Růzicka
Radovan
R
D000818:Animals; D001713:Biphenyl Compounds / Q000138:chemical synthesis / Q000633:toxicity*; D002733:Chlorophenols / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity; D007053:Ice; D008163:Luminescent Measurements; D015394:Molecular Structure; D010575:Pesticides / Q000737:chemistry; D010636:Phenols / Q000633:toxicity*; D010782:Photolysis; D051381:Rats; D012996:Solutions / Q000633:toxicity; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014733:Vibrio / Q000187:drug effects; D014867:Water
C492398:5-chlorobiphenyl-2,4'-diol; D001713:Biphenyl Compounds; D002733:Chlorophenols; D004785:Environmental Pollutants; D007053:Ice; D010575:Pesticides; D010636:Phenols; D012996:Solutions; D014867:Water; C029107:4-chlorophenol; C030683:2-chlorophenol