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

本研究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生理状态的毒害作用，首次开发并成功实现了水相羟基自由基的自动、快速、灵敏测量分析技术。应用于雨和露水样品分析大气水相 OH 自由基来源表明硝酸盐、亚硝酸盐和芬顿反应（涉及过氧化氢和溶解的铁物质）是主要来源。雨、露水样品中的 OH 自由基含量未知，而 OH 的来源（有时高达 50%）仍有待阐明。根据我们的研究，汽油车中产生的OH自由基来源于产生OH的物质，包括硝酸（硝酸盐）、亚硝酸……更多(亚硝酸盐)、过氧化氢和大气中存在的铁物质以及产生 OH 的物质的重要人为来源之一可能是柴油机尾气。 OH自由基产生液（光芬顿试剂）在红松苗针上熏蒸2-3个月，加入甘露醇后，OH的影响大大减弱。暴露实验中在熏蒸液中添加了自由基清除剂，甘露醇有效地控制了OH对松树的毒害作用，而且松树生长模型表明，OH自由基暴露会导致松针光合产量下降。每年接触产生 OH 的物质后，会减少生物量并最终导致树木死亡。一项数值模拟检查了各种人为来源的氮氧化物和二氧化硫的排放趋势。在广岛县，钢铁工业等固定源是这些污染物的主要排放源，但随着节能和成本的新技术的发展，这些污染物的排放量将降低20-30%。从1990年到2010年，主要空气污染物排放量的减少将使该县的空气污染得到显着改善，因此松林进一步减少的可能性不大。