天沙河沉积物中重金属污染特征与生态风险评价

采集天沙河表层沉积物，检测其中Cr、Ni、Cu、Zn、Cd和Pb 6种重金属的含量，分别采用内梅罗指数法(NI)、地累积指数法、Hakanson生态风险指数法和淡水生态系统沉积物基准法(SQGs)对沉积物中重金属污染的特征和生态风险进行评价，并对几种评价方法进行比较。结果表明：鉴于各采样点重金属的污染特征，采用内梅罗指数法和Hakanson生态风险指数法所得结果一致，杜阮河段、白沙河段及天沙河上游污染较严重，天沙河中下游污染程度相对较低；就各重金属的污染特征而言,采用地累积指数法和Hakanson生态风险指数法所得结果基本一致，Cd和Cu污染较严重，其次是Zn、Ni、Pb、Cr；而采用SQGs法的风险评价与其它方法所得结果存在一定差异，其主要原因是SQGs法基于污染物的生物毒性效应，而其他方法多反映单一重金属污染效应或多种重金属综合污染效应

POLLUTION OF HEAVY METALS IN THE SEDIMENTS FROM RIVER AND ITS POTENTIAL ECOLOGICAL RISK ASSESSMENT——FOCUS ON THE TIANSHA RIVER OF THE PEARL RIVER DELTA REGION

The surface sediments from the Tiansha River were sampled and the contents of six heavy metals including Cr,Ni,Cu,Zn,Cd and Pb were measured.The pollution characteristics and ecological risk of heavy metals sediments containing were respectively evaluated by means of Nemerow index,geo accumulation index,Hakanson’s ecological risk index and Sediment Quality Guidelines (SQGs) for freshwater ecosystem.Meanwhile,the comparison of the evaluation methodology was fulfilled.The results showed that the characteristics of heavy metal pollution evaluated by Nemerow index and Hakanson’s ecological risk index reached agreement to each sampling site.The pollution of Duruan,Baisha River basin and the upper reaches of the Tiansha River was more serious than that of the middle and down reaches of the Tiansha River.Besides, the evaluation on pollution risk of each heavy metal acquired general consistence by geo accumulation index and Hakanson’s ecological risk index.Cd and Cu possessed the highest risks,followed by Zn,Ni,Pb,Cr.The consequences deduced by SQGs assessment showed slight differences compared with other approaches,mainly because SQGs index was more susceptible to biotoxicity,and other methods focused on pollution effect of single heavy metal or comprehensive pollution effect of various heavy metal