Pan Shuihong, Feng Chuchu, Lin Jialu, Cheng Lidong, Wang Chengjun, Zuo Yuegang
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, 325035, China.
Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA, 02747, USA.
Environ Sci Pollut Res Int. 2017 Apr;24(12):11289-11298. doi: 10.1007/s11356-017-8708-z. Epub 2017 Mar 16.
The spatial distribution and seasonal variations of methylmercury (MeHg) in Wen-Rui-Tang (WRT) River network were investigated by monitoring the MeHg concentrations in surface water samples collected from 30 sites across the river network over four seasons. Detection frequencies and concentrations of MeHg were generally higher in January, indicating that low sunlight irradiation, wind speed, and temperature conditions might enhance the persistence of MeHg in surface water. The MeHg levels varied with sampling locations, with the highest concentrations being observed in the industrial area especially around wastewater outfall, revealing that the mercury contamination in WRT River mainly comes from the industrial wastewater. Photodegradation of MeHg in WRT River surface water and the effects of natural constituents such as fulvic acid (FA), ferric ions (Fe), nitrate (NO), and dissolved oxygen on the MeHg photodegradation in aqueous solutions were studied under the simulated sunlight. The experimental data indicated that the indirect photodecomposition of MeHg occurred in WRT River surface water. Photodegradation of MeHg in FA solution was initiated by triplet FA* or MeHg-FA* via electron transfer interaction under light irradiations. The Fe and NO can absorb light energy to produce ·OH and enhance the photochemical degradation of MeHg. The MeHg photodecompositions in FA, nitrate, and Fe solutions were markedly accelerated after removing the dissolved oxygen.
通过监测温瑞塘（WRT）河网30个采样点四季采集的地表水样品中的甲基汞（MeHg）浓度，研究了该河网中MeHg的空间分布和季节变化。1月份MeHg的检出频率和浓度普遍较高，表明低光照、低风速和低温条件可能增强了MeHg在地表水中的持久性。MeHg水平随采样地点而变化，在工业区尤其是废水排放口周围观测到最高浓度，这表明温瑞塘河中的汞污染主要来自工业废水。在模拟太阳光下，研究了温瑞塘河地表水MeHg的光降解以及诸如富里酸（FA）、铁离子（Fe）、硝酸盐（NO）和溶解氧等天然成分对水溶液中MeHg光降解的影响。实验数据表明，温瑞塘河地表水发生了MeHg的间接光分解。在光照下，FA溶液中MeHg的光降解是由三重态FA或MeHg-FA通过电子转移相互作用引发的。Fe和NO可以吸收光能产生·OH并增强MeHg的光化学降解。去除溶解氧后，FA、硝酸盐和Fe溶液中MeHg的光分解明显加速。
