硒对土壤中汞形态及其生物有效性的影响  

Effects of selenium on mercury speciation and its bioavailability in paddy soils

作　　者：燕敏[1,2] 郭建阳[1] 冯新斌[1] 张超[1,2] 仇广乐[1] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550002 [2]中国科学院大学,北京100049

出　　处：《生态学杂志》2015年第5期1402-1406,共5页Chinese Journal of Ecology

基　　金：国家重点基础研究发展计划项目(2013CB430004);国家自然科学基金项目(41373135;41273152和41173126)资助

摘　　要：利用连续浸提法研究了硒对稻田土壤中汞的形态分布及其生物有效性的影响。结果显示:加硒前后土壤中汞均以有机结合态、元素态和硫化物态为主,这三者占土壤总汞含量的90%以上,而生物有效态汞(包括模拟胃酸提取态和水溶态)仅占土壤总汞含量的0.27%。加硒对土壤中有机结合态和元素态汞的影响最为显著,随着硒添加浓度的增加,有机结合态汞的相对含量呈逐渐下降的趋势,而元素态汞相反,但土壤中其他形态的汞含量变化不显著。加硒可有效降低土壤中无机汞和甲基汞的生物有效性。结合土壤中汞形态及其生物有效性的变化可以推测:有机结合汞是维持土壤中生物有效态汞的重要补偿来源,当其转化成更为惰性的元素汞后,影响有机结合态汞与生物有效态汞之间的平衡,可能是导致土壤中汞生物有效性降低的主要因素。The influence of selenium （Se） supplementation on mercury （Hg） speciation and its bioavailability in paddy soil was investigated using the sequential selective extraction method. Results showed that organochelated Hg, elemental Hg, and sulfide Hg were dominant, accounting for more than 90% of the total Hg in soils both with and without Se supplementation. The bioavailable portion of Hg in soil was limited, accounting for only 0.27% of the total. Se supplementation had a significant influence on the abundances of organochelated Hg and elemental Hg, but little influence on its other forms. The abundance of organochelated Hg was gradually decreased with the increase of Se supplementation in soils, while the change of elemental Hg was opposite. Se supplementation greatly mitigated the bioavailability of Hg in soils. We postulate that organochelated Hg is the important source for the bioavailable portion of Hg in soils. The shift of the balance between organochelated Hg and bioavailable Hg in soils is probably the main reason for the decreased bioavailability of Hg when the soils were added with Se.

关 键 词：汞 硒 化学形态 生物有效性 土壤 

分 类 号：X53[环境科学与工程—环境工程]