江苏省西部湖泊表层沉积物中重金属分布特征及其潜在生态风险评价

Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediments from the Lakes of West Jiangsu Province

为了掌握江苏省西部湖泊表层沉积物中重金属的污染情况,利用电感耦合等离子体原子发射光谱法（ICP-AES）分析江苏省西部湖泊表层沉积物中As、Cd、Co、Cr、Cu、Ni、Pb和Zn含量,并采用地积累指数法、富集因子法和Hakanson潜在生态风险指数法对各重金属的污染水平以及潜在生态风险进行评价。结果表明,湖泊表层沉积物中As、Cd、Co、Cr、Cu、Ni、Pb和Zn含量分别为11.6~54.9、0.12~0.91、10.06~20.12、44.01~85.91、22.74~54.17、20.31~40.48、21.40~45.23、68.86~254.09 mg.kg-1。地积累指数法和富集因子法的评价结果均表明,Cd和As是主要的污染物,Cu、Zn和Pb在少数位点为轻度污染,Co、Cr和Ni处于无污染水平。Hakanson潜在生态风险指数法评价结果显示,综合风险程度顺序为固城湖（284.43）〉石臼湖（280.93）〉白马湖（212.80）〉玄武湖（200.99）〉高邮湖（136.15）〉洪泽湖（133.42）〉骆马湖（79.28）,单因素方差分析结果表明,这7个湖泊综合潜在生态风险指数存在极显著差异（P=0.001）。因此,固城湖、石臼湖、白马湖和玄武湖表层沉积物重金属潜在生态风险为中等,主要风险污染物为Cd和As,而高邮湖、洪泽湖和骆马湖重金属潜在生态风险较低。

The contents of heavy metals or metalloid(i.e.As,Cd,Co,Cr,Cu,Ni,Pb and Zn) were investigated in surface sediments from the lakes in the Western part of Jiangsu Province through inductively coupled plasma-atomic emission spectrometry(ICP-AES).The contamination level and potential ecological risks of heavy metals were assessed with geo-accumulation index,enrichment factor and potential ecological risk index methods,respectively.It was found that the contents of the heavy metals in the sediments were in the range of 11.6~54.9,0.12~0.91,10.06~20.12,44.01~85.91,22.74~54.17,20.31~40.48,21.40~45.23 and 68.86~254.09 mg·kg-1 for As,Cd,Co,Cr,Cu,Ni,Pb and Zn,respectively.Analysis with geo-accumulation index and enrichment factor methods both indicated that Cd and As were the main pollutants,Cu,Zn and Pb caused light pollution in same sampling sites and Co,Cr and Ni were in clean level.For the different lakes examined in the present study,the general indices of potential ecological risk followed the order of Lake Gucheng(284.43)>Lake Shijiu(280.93)>Lake Baima(224.97)>Lake Xuanwu(200.19)>Lake Gaoyou(136.15)>Lake Hongze(133.42)>Lake Luoma(76.26).One-way ANOVA analysis indicated that very significant difference(P=0.001) existed in the general indices of the different lakes.Therefore,Lake Gucheng,Lake Shijiu,Lake Baima and Lake Xuanwu had moderate ecological risks with Cd and As as the main contributors,while Lake Gaoyou,Lake Hongze and Lake Luoma imposed low ecological risks.