三峡库区消落带土壤淹水过程中汞的释放及甲基化特征  

Releases and methylation of soil mercury in water-level fluctuating zone of the three gorges reservoir region

作　　者：王欣悦[1] 贺春凤[1] 孙荣国[1] 张成[1,2] 王定勇[1,2] 

机构地区：[1]西南大学资源环境学院,重庆400715 [2]重庆市农业资源与环境研究重点实验室,重庆400716

出　　处：《环境化学》2015年第1期172-177,共6页Environmental Chemistry

基　　金：国家重点基础研究发展规划(973)项目(2013CB430004);国家自然科学基金项目(41373113;41173116);中国博士后科学基金(2013M542242)资助

摘　　要：为探索三峡库区消落带土壤淹水期汞的环境化学行为,利用模拟试验,设置A(15℃,低溶解氧(DO))、B(30℃,低DO)、C(15℃,高DO)3组处理,在人工气候培养箱中进行消落带土壤淹水过程中汞的释放与甲基化特征研究,淹水试验共进行了40 d.结果表明,淹水初期(0—10 d)土壤汞呈释放趋势,A、B、C等3组处理水体中总汞浓度逐渐增加,而土壤中总汞含量相应降低;随淹水时间的延长(>10 d),二者达到平衡.淹水后,A、B、C处理上覆水甲基汞浓度随淹水时间的延长而升高,且分别在第15天、第8天、第15天达到峰值,第30天基本达到平衡;土壤甲基汞含量随淹水时间的延长而增高,并在第30天达到平衡,平衡时土壤及上覆水甲基汞浓度规律均表现为B>A>C.土壤-上覆水系统温度的适当升高利于土壤汞的释放及甲基化;高溶解氧利于土壤汞的释放,低溶解氧则更利于汞的甲基化.To understand the environmental fate of mercury in the Three Gorges Reservoir region during the flooding period, three treatments including A （15 ℃, hypoxia）, B （30 ℃, hypoxia） and C （15 ℃, high dissolved oxygen） were conducted in the lab under submerged conditions, and the characteristics of soil mercury release and methylation were evaluated for whole 40 days. The results showed, at the initial submerging period, soil Hg release increased, and total Hg concentration in water of three treatments also increased gradually, but the total Hg concentration in soils decreased. With increasing submerging time （〉10d ） , total Hg concentrations reached equilibrium between soil and underlying waters. After submerging, MeHg concentrations in underlying water increased with submerging period, which were observed in all treatments, and maximum values occurred on the 15^th day, 8^th day and 15^th day respectively. Equilibrium of all treatments was reached on approximately 30^th day. Additionally, MeHg in soils increased with submerging period and also reached equilibrium on the 30^th day. At equilibrium, MeHg concentrations in soils and underlying water were B〉A〉C. Moreover, high temperature in the soil？underlying water system in a certain range enhanced soil Hg release and methylation. Furthermore,high dissolved oxygen concentration also enhanced soil Hg release, but low dissolved oxygen concentration favored of methylation processes.

关 键 词：消落带 淹水过程 汞释放 甲基化 

分 类 号：X53[环境科学与工程—环境工程]