ENVIRONMENTAL SCIENTIFIC EVALUATIION OF PHOTOCHEMICAL REACTIONS IN NATURAL WATER

天然水中光化学反应的环境科学评价

• 批准号: 17310010
• 负责人: OHTA Keiichi
• 金额: $ 10.43万
• 依托单位: The University of Shiga Prefecture
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17310010/
• 关键词: photochemistry; aquatic reaction; DOM degradation; humic substances; pollutant scavenging; organic-metal complex; 光化学反応; 水圏化学; 溶存有機物; 琵琶湖

Aquatic photochemical reactions caused by sunlight are important as a natural removal process for dissolved organic matter (DOM) in water. Little is known, however, about photo-degradation mechanism of humic substances (HS), a major constituent of DOM, and its influence on the photo-degradation of organic pollutants. We conducted field observations in Lake Biwa and inflowing rivers and made laboratory experiments to clarify following points;(a)contribution of photochemical reactions to the distribution of HS in Lake Biwa,(b)photo-degradation of nonyl phenols and other pollutants, (c) photo-degradation and distribution of pesticides in the lake, (d) photo-degradation of DOM in effluent from the waste-water treatment plants, and (e) influence of photo-reactions and DOM on the distribution of iron in the lake.Throughout the present study, we obtained following results.(1) Photochemical degradation of HS results in their lower concentrations at the surface water layer in Lake Biwa as compared to deeper layers.(2) The fluorophore of HS is of higher sensitivity to photo-degradation than chromophore, and photo-degradation of carbon bond take places later. These degradation reactions proceed in the first-order reaction kinetics with reaction rate constants ranging from 0.01 to 0.04.(3) Nonyl phenols and phosphate-esters in water are easily degradable on photo-reaction which is influenced by HS.(4) The pesticides being resistant to photo-reaction can survive for long time, and they are thus detected in Lake Biwa water throughout the whole year.(5) HS in the effluent from waste-water treatment plants emits strong fluorescence. They are easily photo-degraded, showing a possibility that photoreactions can be applicable to high-grade treatment of waste water.(6) Heavy metals like iron form complexes with DOM, which can be susceptible to the photochemical alteration.

光化学反应是水体中溶解性有机物（DOM）的自然去除过程。然而，对于DOM的主要组成部分腐殖物质（HS）的光降解机制及其对有机污染物光降解的影响却知之甚少。我们在琵琶湖和流入的河流中进行了实地观察，并进行了实验室实验，以澄清以下几点;（a）光化学反应对琵琶湖中HS分布的影响，（B）壬基酚和其他污染物的光降解，（c）农药在湖中的光降解和分布，（d）废水处理厂流出物中DOM的光降解，（e）光反应和DOM对铁在湖泊中分布的影响。(1)HS的光化学降解导致其在琵琶湖表层水的浓度低于深层。(2)HS的荧光团对光降解的敏感性高于发色团，碳键的光降解发生较晚。这些降解反应进行的一级反应动力学与反应速率常数范围从0.01到0.04。(3)壬基酚和磷酸酯类化合物在水中易发生光降解，且受HS的影响。(4)抗光反应的农药可以长时间存活，因此全年都可以在琵琶湖水中检测到。(5)污水处理厂排出的污水中的HS会发出强烈的荧光。它们很容易被光降解，显示了光反应可应用于高等级废水处理的可能性。(6)重金属如铁与DOM形成复合物，这可能对光化学变化敏感。

项目成果

In situ generation of refractory organic compounds in Lake Biwa, Japan

日本琵琶湖难熔有机化合物的原位生成

• 发表时间: 2006
• 期刊: Proc. 2nd Japan-Korea Joint Symp (on Limnol)
• 作者: Nohda;C
• 通讯作者: C

溶存腐植物質のキャラクタリゼーション

溶解腐殖质的表征

• 发表时间: 2008
• 作者: Nohda;C.;M.Maruo;S.Bann;K.Ohta;大田 啓一
• 通讯作者: 大田 啓一

Vertical distribution of iron(II) and its relation to organic substances in Lake Biwa, Japan

日本琵琶湖铁(II)的垂直分布及其与有机物质的关系

• 发表时间: 2010
• 期刊: Verh. Internat. Verein. Limnol. 30(9)
• 作者: Masahiro Maruo;Keisuke Tate;KeIIchi Ohta;Kazuhide Hayakawa;Hajime Obata
• 通讯作者: Hajime Obata

Humic substances discharged from sewage treatment plants.

污水处理厂排放的腐殖质。

• 发表时间: 2008
• 期刊: Verh. Internat. Verein. Limnol. 30(印刷中)
• 作者: Ohta;K
• 通讯作者: K

In situ generation of refractory organic compounds in Lake Biwa,Japan

日本琵琶湖难降解有机化合物的原位生成

• 发表时间: 2006
• 期刊: Proc.2nd Japan-Korea Joint Symp.on Limnol
• 作者: Nohda;C.
• 通讯作者: C.