Photokinetics of Azaarenes and Toxicity of Phototransformation Products to the Marine Diatom Phaeodactylum tricornutum

• Published in: Environmental science & technology 1999-12, Vol.33 (23), p.4256-4262
• Main Authors: Wiegman, Saskia, van Vlaardingen, Peter L. A, Peijnenburg, Willie J. G. M, van Beusekom, Sebastiaan A. M, Kraak, Michiel H. S, Admiraal, Wim
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; AZAARENES; Biological and medical sciences; Biological and physicochemical phenomena; BIOLOGY AND MEDICINE, APPLIED STUDIES; Chemicals; DIATOMS; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; ENVIRONMENTAL SCIENCES; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Light; Marine and brackish environment; Marine biology; Natural water pollution; Phaeodactylum tricornutum; PHOTOCHEMICAL REACTIONS; Pollution; Pollution, environment geology; Seawaters, estuaries; TOXICITY; Ultraviolet radiation; WATER CHEMISTRY; WATER POLLUTION; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es990228q

UV radiation is absorbed by PAHs, structurally altering these compounds into a variety of oxygenated products. Until recently, only hazards of parental PAHs in the environment were investigated. This study aims to determine the fate and effects of azaarenes (N-heterocyclic PAHs) together with their photoproducts in marine environments. Photoreaction kinetics of eight azaarenes, ranging from two-ringed to five-ringed structures, were examined using two different light sources:  one with an emission peak at 300 nm (UV−B) and the other with an emission peak at 350 nm (UV−A). Azaarenes degraded rapidly in the presence of short-waved light, UV−B being more effective than UV−A. Especially preexposure of azaarenes to UV−A radiation led to products toxic to the marine diatom Phaeodactylum tricornutum. Since UV−A constitutes a larger fraction of sunlight at the earth surface and in the water column, photolysis by UV−A may increase the toxic risk of aromatic compounds in the marine environment.