Aqueous photochemical degradation of hydroxylated PAHs: Kinetics, pathways, and multivariate effects of main water constituents
Aqueous photochemical degradation of hydroxylated PAHs: Kinetics, pathways, and multivariate effects of main water constituents
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羟基化多环芳烃的水相光化学降解：主要水成分的动力学、途径和多元效应
DOI：
10.1016/j.scitotenv.2015.12.143
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发表时间：
2016-03-15
影响因子：
9.8
通讯作者：
Yao, Ziwei
中科院分区：
文献类型：
--
作者：
Ge, Linke;Na, Guangshui;Yao, Ziwei
羟基化多环芳烃（Hydroxylated polycyclic aromatic hydrocarbons，OH-PAHs）是近年来备受关注的水环境污染物，了解其环境转化和毒性具有重要意义。研究了4种羟基多环芳烃9-羟基芴（9-OHFL）、2-羟基芴、9-羟基菲和1-羟基芘在模拟太阳光（λ> 290 nm）照射下的光化学行为。结果表明，它们的光降解符合准一级动力学。根据测定的量子产率，计算出它们在北纬45度的表面沃茨中的太阳表观光降解半衰期，从9-羟基菲的0.4 min到9-OHFL的7.5 x 10（3）min不等，表明OH-多环芳烃在阳光照射的表面沃茨中会快速光降解。以9-OHFL为例，在纯水中，它能直接光解，并通过.OH而不是O-1（2）自敏化光氧化。9-OHFL在自然沃茨中的光降解速度比在纯水中慢，这是由于Fe（III）、NO3-、Cl-和腐殖酸等光活性物质的综合作用。进一步用费氏弧菌（Vibrio fischeri）检测了光解后的9-OHFL的毒性，发现光解后的9-OHFL在纯水和海水中的毒性均未显著降低（p > 0.05），表明某些中间体的毒性相当或更高。这些结果对于评估地表沃茨中OH-PAHs的归趋和风险具有重要意义。(C)© 2016 Elsevier B. V.版权所有。
Hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) are contaminants of emerging concern in the aquatic environment, so it is of great significance to understand their environmental transformation and toxicity. This study investigated the aqueous photochemical behavior of four OH-PAHs, 9-Hydroxyfluorene (9-OHFL), 2-Hydroxyfluorene, 9-Hydroxyphenanthrene and 1-Hydroxypyrene, under simulated sunlight irradiation (lambda > 290 nm). It was observed that their photodegradation followed the pseudo-first-order kinetics. Based on the determined quantum yields, their calculated solar apparent photodegradation half-lives in surface waters at 45 degrees N latitude ranged from 0.4 min for 9-Hydroxyphenanthrene to 7.5 x 10(3) min for 9-OHFL, indicating that the OH-PAHs would intrinsically photodegrade fast in sunlit surface waters. Furthermore, 9-OHFL as an example was found to undergo direct photolysis, and self-sensitized photooxidation via.OH rather than O-1(2) in pure water. The potential photoreactions involved photoinduced hydroxylation, dehydrogenation and isomerization based on product identification by GC-MS/MS. 9-OHFL photodegraded slower in natural waters than in pure water, which was attributed to the integrative effects of the most photoreactive species, such as Fe(III), NO3-, Cl- and humic acid. The photomodified toxicity was further examined using Vibrio fischeri, and it was found that the toxicity of photolyzed 9-OHFL did not decrease significantly (p > 0.05) either in pure water or in seawater, implying the comparable or higher toxicity of some intermediates. These results are important for assessing the fate and risks of OH-PAHs in surface waters. (C) 2016 Elsevier B.V. All rights reserved.