龙江河沉积物重金属污染特征及生态风险评价  

Pollution characteristics of heavy metals in Longjiang River sediments and ecological risk assessment

作　　者：散剑娣 蔡德所[1] 靖志浩 杨佳星 李书恒 陈声震 SAN Jiandi;CAI Desuo;JING Zhihao;YANG Jiaxing;LI Shuheng;CHEN Shengzhen(College of Hydraulic and Environment,China Three Gorges University,Yichang 443000,China;China National Chemistry Southern Construction&Investment Co.,Ltd.,Guangzhou 510000,China)

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443000 [2]中化学南方建设投资有限公司,广东广州510000

出　　处：《人民长江》2021年第11期34-41,共8页Yangtze River

基　　金：国家自然科学基金项目(40971280)。

摘　　要：为了解广西龙江河表层沉积物中重金属的污染状况,于2018年3月采集12个样点的沉积物样品,测定沉积物中重金属Cu、Zn、Pb、Cd、Cr、As的含量和赋存形态,运用地累积指数法、潜在生态风险指数法对沉积物中重金属的污染程度和生态风险进行评价,并分析了沉积物中重金属的来源。结果表明:①除Cr的平均含量近似于背景值外,Cd、Pb、As、Zn、Cu的平均含量分别为背景值的57.88,7.12,6.30,4.19,2.17倍。②Cr和As以残渣态为主;Zn在中上游碳酸盐结合态含量较高,在下游铁锰氧化物结合态含量较高;Cu和Pb的铁锰氧化物结合态和有机物结合态含量较高;Cd以铁锰氧化物结合态和碳酸盐结合态为主,与2013年相比,铁锰氧化物结合态含量大幅度减少,碳酸盐结合态含量大幅度增加。③地累积指数表明,Cr为未污染,Cu为轻度污染,Zn和As为偏中度污染,Pb为中度污染,Cd为严重污染。潜在生态风险指数表明,Cu、Zn、Pb和Cr 4种元素均为低生态风险,As和Cd元素生态风险指数较大。④沉积物重金属相关性表明,Cu、Zn、Pb、Cr、As 5种元素存在明显同源性。通过沉积物重金属主成分分析,发现第一主成分(Cu、Zn、Pb、Cr)的来源为工业源,第二主成分(Cd)的来源为农业活动及采矿活动,第三主成分(As)的来源为矿业活动。In order to understand the pollution status of heavy metals in the surface sediments of the Longjiang River in Guangxi,12 sediment samples were collected in March 2018 to determine the content and speciation of heavy metals Cu,Zn,Pb,Cd,Cr and As in the sediment.The pollution degree and ecological risk of heavy metals in sediments were evaluated by geo-accumulation index method and potential ecological risk index method,and the sources of heavy metals in sediments were analyzed.The results showed that:①Except that the average content of Cr was close to the background value,the average content of Cd,Pb,As,Zn and Cu were respectively 57.88,7.12,6.30,4.19 and 2.17 times of the background value.②Cr and As were mainly in residual form;Zn had high content of carbonate-bound form in the middle and upper reaches,and high content of Fe-Mn oxide form in the downstream;Cu and Pb had high content of Fe-Mn oxide form and organic binding state;Cd was dominated by Fe-Mn oxide form and carbonate-bound form.Compared with 2013,the content of Fe-Mn oxide form had been greatly reduced,and the content of carbonate-bound form had greatly increased.③The geo-accumulation index showed that it was not polluted for Cr,slightly polluted for Cu,slight-moderately polluted for Zn and As,moderately polluted for Pb,and seriously polluted for Cd.The potential ecological risk index showed that Cu,Zn,Pb and Cr had low ecological risk,while As and Cd had high ecological risk index.④The correlation of heavy metals in sediments showed that Cu,Zn,Pb,Cr and As had obvious homology.Through the principal component analysis of heavy metals in sediments,it was found that the first principal component(Cu,Zn,Pb,Cr)was from industrial sources,the second principal component(Cd)was from agricultural activities and mining activities,and the third principal component(As)was from mining activities.

关 键 词：重金属 沉积物 地累积指数法 潜在生态风险指数法 污染程度 生态风险评价 龙江河 

分 类 号：X822[环境科学与工程—环境工程]