丹江口水库典型库湾及支流沉积物重金属污染分析及生态风险评价  

ANALYSIS OF HEAVY METALS POLLUTION AND ECOLOGICAL RISK ASSESSMENT IN THE SEDIMENTS FROM THE REPRESENTATIVE RIVER MOUTHS AND TRIBUTARIES OF THE DANJIANGKOU RESERVOIR

作　　者：雷沛[1,2] 张洪[1] 单保庆[1] 

机构地区：[1]中国科学院生态环境研究中心环境水质学国家重点实验室,北京100085 [2]武汉理工大学资源与环境工程学院,湖北武汉430070

出　　处：《长江流域资源与环境》2013年第1期110-117,共8页Resources and Environment in the Yangtze Basin

基　　金：水利部公益性行业科研专项项目(200901008);水利部公益性行业科研专项项目(201101001)

摘　　要：对丹江口水库上游汉江支流及库湾沉积物中6种重金属元素的污染特征进行分析,采用效应阈值标准(NYSDEC)和Lars Hkanson潜在生态风险指数评价重金属的污染程度和环境风险。研究表明,库湾沉积物与支流沉积物中Ni、Pb含量较为接近;库湾沉积物中Cd、Cr、Cu、Zn含量分别高达1.86、271.2、99.91、478.3mg/kg,均超过支流沉积物中相应重金属含量2倍以上。各采样点表层(0～10cm)沉积物中Pb含量均低于LEL值(最低效应阈值),Cd、Ni含量均介于LEL值和SEL值(最高效应阈值)之间,而Cr、Cu、Zn含量均有超过SEL值的现象发生。考察沉积物重金属的富集程度发现各采样点表层沉积物中Ni和Pb均未发生富集,而Cd、Cr、Cu和Zn均存在不同程度的富集,其平均富集系数分别为7.12、1.80、1.63和2.84。根据重金属含量的相关性可知Ni和Pb主要来自于天然地球化学来源,而Cd、Cr、Cu和Zn则主要受人为源影响。以丹江口库区土壤(黄棕壤)中重金属背景值为参比,发现表层沉积物总体处于高生态风险,且以Cd生态风险为主;参与评价的5种重金属潜在生态风险程度顺序为Cd>Cu>Cr>Zn>Pb。Riverine sediment cores of the Hanjiang River tributaries and corresponding river mouths in the upper reach of the Danjiangkou Reservoir were taken to analyze the sedimentary heavy metal contents at vertical profile,then environmental risk of those metals was assessed by using both effects limits （the standard of New York state department of environmental conservation,NYSDEC） and Lars H0kanson po- tential ecological risk index. The results showed that contents of Cd,Cr,Cu,and Zn in the sediment cores from the river mouth were 1.86,271.2,99.91 and 478.3 mg/kg, respectively, which were at least 2 times than those in the Hanjiang River tributaries. According to NYSDEC guidlines,contents of Pb in the surface sediments （0-10 cm） were below LEL （Lowest Effect Level） value,and it was between LEL and SEL （Se- vere Effect Level） value for Cd,as well as for Ni. However, contents of Cr,Cu and Zn in certain layer of surface sediments exceeded their respective SEL values,indicating severely sedimentary pollution. Enrich- ment factors for Cd,Cr,Cu and Zn in surface sediments were 7.12,1.80,1.63 and 2.84, respectively. Cor- relation analysis revealed that Ni and Pb were originated from natural sources, while Cd, Cr, Cu and Zn were mainly influenced by anthropogenic activities. Compared to the background values of the Danjiangkou Reservoir, the studied heavy metals in the surface sediments had a high ecological risk in sequence as follow Cd 〉 Cu 〉Cr）Zn〉Pb.

关 键 词：沉积物 重金属 生态风险 库湾 支流 丹江口水库 

分 类 号：X524[环境科学与工程—环境工程]