广州市流花湖沉积物重金属污染特征及潜在生态风险评估

近年来重金属污染日益加重,对人类及水生态系统健康产生较大危害。本研究选择广州市典型城市湖泊——流花湖,利用地累积指数(Igeo)、潜在生态风险指数(RI)对沉积物中12种重金属的污染水平、垂向分布特征及其潜在生态风险进行评价,并通过多元统计分析对金属元素的来源进行解析。结果表明:①湖泊沉积物重金属含量(Mn、V除外)均显著高于区域土壤背景值,自下而上呈现先增加后减少的趋势;②地累积指数评价结果显示Cd、Zn、Sb、Cu、Pb和As这6种重金属污染较严重,其中Cd偏重度污染的状态(Igeo=3.89);③不同重金属元素污染水平有较大差异,Cd、Cu、Zn、Sb、Pb、As、Ni、Cr、Tl、Co的单个重金属污染指数(Cif)均为中等污染水平以上,而生态风险系数(Eif)表现为Cd(Eif=818.6)极严重等级,Sb(Eif=82.64)重度风险等级,其他10种重金属Eif均为轻度风险等级;④该湖RI指数变化幅度剧烈(105.85

Assessment on the Characteristics of Heavy Metal Pollution and Potential Ecological Risk in Sediments of Liuhua Lake of Guangzhou Municipality

In recent years,the increasing pollution of heavy metals has brought great harm to health of human being and water ecosystem.The typical urban lake,Liuhua Lake in Guangzhou Municipality,was selected for the evaluation on the pollution level,vertical distribution characteristics and potential ecological risk of 12 heavy metals in sediments by using indexes of geo-accumulation(Igeo)and the potential ecological risk index(RI).The results show that,①the heavy metal contents(except Mn,V)in lake sediments are significantly higher than the contents in the regional soil background,appearing the tendency of increase first and then decrease from bottom to top;②Igeo results show that the 6 kinds of heavy metals,Cd,Zn,Sb,Cu,Pb and As,are of seriously polluted,and the pollution state of Cd(Igeo=3.89)was most serious;③the pollution levels of different heavy metal elements are quite different.The single heavy metal pollution indexes(Cif)of Cd,Cu,Zn,Sb,Pb,As,Ni,Cr,Tl,Co are above the medium pollution level,while the ecological risk coefficient(Eif)shows that Cd(Eif=818.6)is at extreme serious grade,Sb(Eif=82.64)is at severe risk level,and the other 10 kinds of heavy metal Eif are all at light risk level;④the RI of the lake changed sharply(105.85