Concentration and distribution of Cadmium (Cd) in the surface water and sediment of the north part of Taihu Lake were studied. The results showed the concentrations of Cd detected in the water body and sediment ranged from 69.35~ 85.11 ng/L which was at a low contamination level. The concentrations of Cd detected in the surface sediment ranged from 0.70 ~ 2.84 mg/kg, which brought potential environmental risks. In the sediment profiles, Cd contents had a trend of decreasing with depth. There were significant differences among sampling points about the concentration and ratio of different speciations of Cd. The ratios of weak acid soluble fraction, reducible fraction and oxidizable fraction of Cd in Meiliang Bay and Huanshan River were higher, which existed stronger biological availability, and Cd mainly existed in residual fraction with huge proportion in Zhushan Bay. The form distribution of Cd was coherence with the content of the total Cd, which showed positively correlated with the total Cd and followed the sequence Zhushan Bay> Meiliang Bay and Huanshan River, therefore, there existed larger Cd ecological risks in Zhu Shan Bay sediment. The spatial distribution differences of Cd contents in surface water and sediment were mainly related to the sewage discharge around the lake bays and the accumulation and settlement of the cyanobacteria under the flows.%对太湖北部湖区水体及沉积物中Cd含量、形态分布及其可能产生的环境风险进行了研究.结果表明,太湖北部湖区水体Cd质量浓度为69.35～85.11 ng/L,处于低剂量范围；表层沉积物中Cd质量比范围为0.70 ～ 2.84mg/kg,存在一定的潜在环境污染风险,但沉积物中Cd含量随着深度的增加逐渐降低.沉积物中不同形态Cd的含量及其比重在各点位间均存在明显差别,梅梁湾及环山河底泥中酸溶态、可氧化态和可还原态Cd所占比重均较高,存在较强的生物可利用性,而竺山湾中残渣态比重最高；各形态Cd含量的总体分布趋势与沉积物中Cd总量基本一致,表现为竺山湾＞梅梁湾及环山河,且与Cd总量呈现出显著相关关系,竺山湾沉积物Cd的生态风险较大.水体与沉积物中Cd含量的空间分布差异主要与湖湾周围的污水排放及湖流作用下的蓝藻堆积沉降有关.
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