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Measurement of atmospheric aqueous phase OH radical and the elucidation of its toxic effects on higher plants

大气水相OH自由基的测量及其对高等植物的毒性作用的阐明

基本信息

批准号：
14380244
负责人：
SAKUGAWA Hiroshi
金额：
$ 9.66万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Chemistry of atmospheric aqueous phase hydroxyl radical (OH radical) and its toxic effects on the physiological status of higher plants have been investigated in this study. Analytical technique for automatic, rapid and sensitive measurement of aqueous phase OH radical was firstly developed and it was successively applied to the analysis of rain and dew samples. Identifications of sources of atmospheric aqueous phase OH radical indicated that nitrate, nitrite and Fenton reaction (involving hydrogen peroxide and dissolved iron species) are major sources of OH radical in rain, dew samples whereas unknown sources of OH (sometimes up to 50%) remain to be elucidated. The ppb level of nitrite existed in bubbling solution of the exhaust gas of diesel cars produced uM/h of OH whereas almost no OH generated in that of gasoline cars. From our studies, it can be concluded that atmospheric aqueous phase OH radical is originated from OH producing substances including nitric acid (nitrate), nitrous … More acid (nitrite), hydrogen peroxide with iron species occurring in the atmosphere and one of important anthropogenic sources of OH producing substances may be diesel exhausts. Decrease of photosynthetic activity and stomata conductance at leaf level and the decrease of biomass at individual level were observed when the OH radical generating solution (photo-Fenton reagent) that was fumigated on needles of red pine seedlings for 2-3 months. Interestingly, the influence of OH much diminished when mannitol (radical scavenger) was added into the fumigating solution in the exposure experiment and thus mannitol effectively controlled the toxic effect of OH to pine trees. Moreover, a growth model for pine trees showed that the decrease of photosynthetic production of pine needles with OH radical exposure would reduce biomass quantity and finally cause the death of tree after year-to-year exposure of OH producing substances. A numerical simulation examined emission trends of nitrogen oxides and sulfur dioxide from various anthropogenic sources in Hiroshima prefecture. In the prefecture, stationary sources such as iron and steel industry are major emitters of these pollutants. However, with the development of new technologies for saving the energy and cost, the emission of these pollutants will be lower by 20-30% from 1990 to 2010. This decrease of major air pollutant emissions would result in significant improvement of air pollution in the prefecture and thus further pine forest decline would be unlikely. Less

本文研究了大气水相羟基自由基（OH自由基）的化学性质及其对高等植物的毒害作用。首次开发了自动、快速、灵敏测定水相OH自由基的分析技术，并成功地应用于雨露样品的分析。大气水相OH自由基来源的鉴定表明，硝酸盐、亚硝酸盐和芬顿反应（包括过氧化氢和溶解铁）是雨水、露水样品中OH自由基的主要来源，而未知的OH自由基来源（有时高达50%）仍有待阐明。柴油汽车尾气鼓泡液中亚硝酸盐的浓度为ppb，产生的OH为μ M/h，而汽油汽车尾气鼓泡液中几乎不产生OH。研究表明，大气水相OH自由基主要来源于产生OH的物质，包括硝酸（硝酸盐）、亚硝酸盐、亚硝酸 ...更多信息酸（亚硝酸盐）、过氧化氢和存在于大气中的铁物种，并且产生OH的物质的重要人为来源之一可能是柴油机废气。用OH自由基产生液（Photo-Fenton试剂）熏蒸红松幼苗针叶2-3个月，观察到叶片光合活性和气孔导度下降，单株生物量下降。在暴露试验中，加入自由基清除剂甘露醇后，OH的影响明显减弱，从而有效地控制了OH对松树的毒害作用。此外，松树生长模型表明，OH自由基暴露导致松针光合产物的减少，导致生物量的减少，并最终导致松树死亡。数值模拟研究了广岛县各种人为源氮氧化物和二氧化硫的排放趋势。在该县，钢铁工业等固定污染源是这些污染物的主要排放源。但是，随着节能降耗新技术的发展，从1990年到2010年，这些污染物的排放量将减少20-30%。主要空气污染物排放量的减少将导致该县空气污染的显着改善，因此松树林的进一步减少是不太可能的。少