三峡库区涪陵段消落带铅镉形态特征的研究  

Morphological Features of Pb and Cd in the Water-level Fluctuation Zone in Fuling Section of the Three Gorges Reservoir

作　　者：王春波 方卢秋[1,2] 冉纯民 唐艺玲 邹奇慧 WANG Chunbo;FANG Luqiu;RAN Chunmin;TANG Yiling;ZOU Qihui(School of Chemistry and Chemical Engineering,Yangtze Normal University,Chongqing 408100,China;Research Center for Environmental Monitoring,Hazard Prevention of Three Gorges Reservoir,Yangtze Normal University,Chongqing 408100,China)

机构地区：[1]长江师范学院化学化工学院,重庆408100 [2]长江师范学院三峡库区环境监测与灾害防治工程研究中心,重庆408100

出　　处：《三峡生态环境监测》2018年第1期7-12,共6页Ecology and Environmental Monitoring of Three Gorges

基　　金：重庆市科委项目(cstc2016shmszx20007);重庆市教委大学生创新创业训练计划项目(201610647297)

摘　　要：对三峡库区涪陵段梨香溪、渠溪口等17条长江一级支流消落带土壤样品进行重金属铅(Pb)、镉(Cd)全量分析,选取含量较高的蛇颈河、乌杨溪等土壤样品,采用Tessier五步连续提取法分离重金属形态,以原子吸收法进行定量测定。结果表明,消落带土壤样品的铅全量平均值为26.889 3 mg/kg、镉全量平均值为0.248 2 mg/kg,大部分符合国家环境质量Ⅱ级标准,分布于涪陵段长江干流北岸的支流消落带较南岸支流的重金属含量较高。内梅罗指数平均值为0.93,污染程度评价处于警戒限。在重金属形态分析中,残渣态铅、残渣态镉分别占形态总量的20.92%,17.67%,两者残渣态所占形态总量比例小,形态稳定性较差;铅镉以对水环境和生物具有潜在风险的铁锰氧化物结合态为主,两者具有化学活性、易还原性,分别占形态总量的30.02%,31.51%。根据风险评价准则,重金属Pb,Cd的有效态含量分别为30.56%和38.51%,两者都高于30%,对环境构成了高风险,因此,有关部门应加强进入消落带的废弃物处置与管理,加大农业面源污染物的防控,以减少消落带的污染。The total analysis of heavy metal lead and cadmium was conducted for soil samples in Fuling zone of the Three Gorges Reservoir area.The heavy metal forms were separated by Tessier five-step extraction method and quantified by atomic absorption method.The average amount of lead in the soil samples was 26.889 3 mg/kg,and the average cadmium content was 0.248 2 mg/kg,indicating that most of them met Grade II standards of national environmental quality.The mean value of Nemerow index was 0.93,implying that the pollution degree was evaluated within warning limit.The tributaries in the north bank of Fuling zone had a higher level of heavy metals than those of the south bank.In speciation analysis of heavy metals,residual lead and cadmium accounted for 20.92%and 17.67%,respectively,both were small in proportion to the total amount of speciation with a poor morphological stability.The forms of both metals were dominated by the combined iron and manganese ox?ides at 30.02%and 31.51%of the total speciation,respectively,which are chemically active and reducible with potential risks to water environment and organisms.The available content of lead and cadmium were 30.56%and 38.51%,respectively,and reflected a high risk to the environment in Fuling riparian zone according to the risk of assessment standards with a safety threshold value of less than 30%.Therefore,the relevant departments should strengthen the management and disposal of wastes into the riparian zone,increase the prevention and con?trol of agricultural non-point source pollutants,to reduce the fluctuating zone pollution.

关 键 词：三峡库区 涪陵段 消落带 土壤 铅 镉 

分 类 号：X825[环境科学与工程—环境工程]