玄武湖沉积物中重金属污染的潜在生物毒性风险评价

采用ICP－MS仪测定了玄武湖沉积物中Zn、Cd、Ni的含量，并应用沉积物质量基准法(SQGs)和地累积指数法（Igeo）对重金属的潜在生物毒性进行分析。结果表明：玄武湖沉积物中Zn、Cd和Ni的含量分别为7526~17911、517~898和4776~14728 mg/kg，分别是为南京土壤环境背景值的108~291、5170~8980和133~411倍，表明Zn的污染程度较轻，Cd和Ni的污染较重，且人为活动对重金属含量有重要影响。沉积物中重金属的分布具有明显的区域特征，Zn、Cd、Ni浓度的最大均值均出现于东南湖(SE L)的沉积物中。利用地累积指数法和生物数据库基准对玄武湖表层沉积物进行生物毒性风险评价得出的结论与此相似，潜在生物毒性风险的顺序依次为Cd＞Ni＞Zn。从采样点的布设来看，东南湖的潜在生物毒性风险最严重。

POTENTIAL BIOLOGICAL TOXICITY ASSESSMENT ON HEAVY METAL POLLUTION IN SURFACE SEDIMENTS OF XUANWU LAK

The contents of Zn,Cd and Ni in the sediment of Xuanwu Lake were measured with ICP-MS,and their potential biological toxicity was analyzed using sediment quality guidelines(SQGs)and geo-accumulation index.The contents of Zn,Cd and Ni in the sediments of Xuanwu Lake were 75.26~179.11,5.17~8.98 and 47.76~147.28 mg/kg,respectively,and the contents of Zn,Cd,Ni were respectively 1.08~2.91,51.70~89.80 and 1.33~4.11 times of the their background values in soil environment in Nanjing.These suggested that the pollution degree of Zn was slight in Xuanwu Lake while Cd and Ni were much serious,which may be affected by human activities significantly.The contents of heavy metals were not evenly distributed in sediments of Xuanwu Lake.The maximum mean and peak concentrations values of Cd and Ni were in the Southeast Lake(SE-L),indicating that it was polluted by heavy metals significantly.Similar results were also obtained through appraising the biological toxicity risk on the surface sediments in Xuanwu Lake using geo-accumulation index and biology database guideline.The potential biological toxicity risk in sequence was Cd>Ni>Zn,and among these sampling points,SE-L had the highest potential risk on biological toxicity.