干湿交替条件下三峡水库消落带土壤汞形态变化

应用生态学报

干湿交替条件下三峡水库消落带土壤汞形态变化

张成^1,2,宋丽¹,王定勇^1,2**,张金洋¹,孙荣国¹

(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 400715)

出版日期:2013-12-18 发布日期:2013-12-18

Mercury speciation transformation in soil of the waterlevelfluctuating zone in the Three Gorges Area under alternative dry-wet condition.

ZHANG Cheng^1,2, SONG Li¹, WANG Ding-yong^1，2, ZHANG Jin-yang¹, SUN Rong-guo¹

(¹College of Resources and Environment, Southwest University, Chongqing 400715, China; ²Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400715, China)

Online:2013-12-18 Published:2013-12-18

摘要/Abstract

摘要：

对三峡水库消落带干湿交替条件下土壤汞赋存形态变化、影响因素和生物可利用性进行了模拟研究.结果表明: 干湿交替条件下土壤汞会发生形态转化和释放,总汞含量逐渐降低,两次“淹水-落干”后总汞含量降低了28.9%.土壤中不同汞形态所占比例分别为:水溶态汞(Hg-w)6.1%～16.8%;交换态汞(Hg-e)5.8%～12.9%;碳酸盐结合态汞(Hg-c)4.5%～17.7%;腐植酸结合态汞(Hg-h)12.5%～29.9%;有机质结合态汞(Hg-o)5.3%～12.8%,残渣态汞(Hg-r)34.5%～51.6%.土壤中汞形态以残渣态(Hg-r)为主,干湿交替条件下其所占比例有降低的趋势,腐植酸结合态汞(Hg-h)则逐渐增加,生物可利用态汞(Hg-w、Hg-e、Hg-c和Hg-h之和)总体呈增加趋势,易被水生生物利用并进入食物链,可能会增加水库生态系统的汞生态风险.

Abstract: The speciation transformation, influencing factors, as well as bioavailability of mercury (Hg) in soil of the water levelfluctuating zone in the Three Gorges Reservoir Area were simulated. The results showed that Hg in soil under alternative drywet condition could be transformed and released. The total Hg content in the soil was decreased by 28.9% after two “wetdry” cycles. The percentages of the six Hg species (watersoluble, exchangeable, carbonatebound, humicsbound, organicsulf and residual Hg) were 6.1%-16.8%, 5.8%-12.9%, 4.5%-17.7%, 12.5%-29.9%, 5.3%-12.8%, and 34.5%-51.6%, respectively. It was found that Hg in soils was dominantly residue Hg, whose percentage tended to decrease under alternative drywet condition. The percentage of humicsbound Hg increased gradually and an increase of the percentage of bioavailable Hg (including watersoluble, exchangeable, carbonatebound, and humicsbound Hg) after two wet-dry cycles were observed. Bioavailable Hg could be easily absorbed by aquatic organisms to enter the food chain, which might increase the ecological risk of Hg in the reservoir.

张成1,2,宋丽1,王定勇1,2**,张金洋1,孙荣国1. 干湿交替条件下三峡水库消落带土壤汞形态变化[J]. 应用生态学报.

ZHANG Cheng1,2, SONG Li1, WANG Ding-yong1，2, ZHANG Jin-yang1, SUN Rong-guo1. Mercury speciation transformation in soil of the waterlevelfluctuating zone in the Three Gorges Area under alternative dry-wet condition.[J]. Chinese Journal of Applied Ecology.