Ecological pollution caused by heavy metals released from sediments is a worldwide concern. However, the effect of changes in sediment speciation on their release of heavy metals has not been adequately reported. In this study, the research focused on Pb and Cr in the ice period of Wuliangsuhai. This study analyzed changes in the sediment speciation of Pb and Cr before and after a release experiment using four risk assessment methods while varying the temperature, pH, and salinity of the water column. The results indicated that the total concentration of Pb ranged from 11.17 to 24.25 mg/kg, while for Cr it ranged from 42.26 to 69.68 mg/kg. Both elements exhibited mild contamination. The release of Pb and Cr from sediments increases with increasing water temperature, mainly due to the conversion of the residual fraction of Pb to the Fe–Mn oxide fraction and Cr converting more residual fraction to the organic matter and sulfide fraction. The release of sediment Pb and Cr decreased with increasing pH, with Pb converting more acid extractable fraction to the residual fraction and Cr converting more organic matter and sulfide fraction to the residual fraction. In contrast, the release of Pb and Cr increased and then decreased with increasing salinity. For Pb, the acid extractable fraction was more susceptible to conversion to the residual fraction by environmental influences, whereas for Cr, the organic matter and sulfide fraction were susceptible to conversion to the residual fraction.

沉积物释放的重金属造成的生态污染是世界范围内关注的问题。然而，沉积物形态变化对其重金属释放的影响尚未得到充分报道。本研究主要对乌梁素海冰期的Pb和Cr进行研究。本研究使用四种风险评估方法，同时改变水体的温度、pH 值和盐度，分析了释放实验前后沉积物中 Pb 和 Cr 形态的变化。结果表明，Pb的总浓度范围为11.17至24.25 mg/kg，而Cr的总浓度范围为42.26至69.68 mg/kg。两种元件均表现出轻度污染。沉积物中 Pb 和 Cr 的释放随着水温的升高而增加，主要是由于 Pb 的残留部分转化为 Fe-Mn 氧化物部分，而 Cr 将更多的残留部分转化为有机质和硫化物部分。沉积物中Pb和Cr的释放随着pH值的增加而减少，Pb将更多的酸可萃取部分转化为残余部分，而Cr将更多的有机物和硫化物部分转化为残余部分。相反，Pb和Cr的释放量随着盐度的增加先增加后减少。对于Pb，酸可萃取部分更容易因环境影响而转化为残留部分，而对于Cr，有机物和硫化物部分更容易转化为残留部分。