关键词: 表层沉积物, 重金属, 分布, 生物毒性风险

Abstract:

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.

Key words: surface sediment, heavy metals, distributions, biological toxicity risk