黄河甘宁蒙段表层沉积物中磷的释放风险评估

Risk assessment of phosphorus release from surface sediments in the Gansu,Ningxia and Inner Mongolia sections of the Yellow River

预测表层沉积物中磷释放风险对水环境的治理和磷负荷的调控具有重要意义。基于磷释放风险指数(ERI)的两种计算方法,评估了黄河甘宁蒙段不同水期表层沉积物中的磷释放风险。结果表明:通过磷吸附指数(PSI)和磷吸附饱和度(DPS)得到的ERI表明,研究区域除S5、K3、K11和K12具有中度磷释放风险外,其余各采样点均为高度磷释放风险;通过最大吸附量和沉积物磷饱和度(SPS)得到的ERI表明,研究区域除S5、S11、S12、K3和K11具有中度磷释放风险外,其余各采样点均为高度磷释放风险。建立一个统一的磷释放风险评估方法是今后该领域的研究方向。黄河甘宁蒙段要密切关注环境条件发生变化,特别是上覆水pH下降后,表层沉积物中酸提取态磷的大量溶解所导致的高度磷释放风险。

Predicting the risk of phosphorus release in surface sediments had great significance for water environment management and phosphorus load regulation.Based on two calculation methods of phosphorus release risk index,the risks of phosphorus release from surface sediments in the Gansu,Ningxia and Inner Mongolia sections of the Yellow River in different water periods were evaluated.The results showed that the eutrophication rise index(ERI)obtained by phosphorus sorption index(PSI)and degree of phosphorus saturation(DPS)showed that in the study area,there was a moderate risk of phosphorus release in S5,K3,K11 and K12,while the remaining sampling points were all at a high risk of phosphorus release;the ERI obtained by maximum adsorption capacity and sediment phosphorus saturation(SPS)showed that in the study area,there was a moderate risk of phosphorus release in S5,S11,S12,K3 and K11,while the remaining sampling points were all at a high risk of phosphorus release.The future research direction in this field was to establish a unified assessment method for risk assessment of phosphorus release.It was necessary to pay attention to the high risk of phosphorus release from surface sediments caused by changes of environmental conditions,especially the dissolution of HCl-P caused by the reduction of pH in the Gansu,Ningxia and Inner Mongolia sections of the Yellow River.