乌江流域水库沉积物中生物硅的测定方法及其环境意义

Determination of Biogenic Silica in Sediments of Reservoirs in the Wujiang River and its Environment Significance

采用碱提取法中的单点法与多点法相结合,测定了乌江流域水库沉积物中生物硅的含量,并对多点提取法进行了改良。采用多个离心管分装定量样品进行连续振荡,每小时提取1个样品进行测定。对多个时间点的提取结果,利用线性回归法分析得出最佳提取时间,优化最佳提取液,然后利用单点提取-硅钼蓝检测法测定沉积物中生物硅的含量。该方法既保证了单点法的快速,也减小了多点法的多次提取操作与提取时的体积误差。本文根据测定结果探讨了乌江流域水库沉积物中生物硅含量变化规律及其环境意义。

In this study,biogenic Silica in sediments of reservoirs in the Wujiang Drainage Basin was determined,by means of the wet-alkaline extraction procedure with the combination of single-point and multi-point extraction methods.The multi-point extraction procedure was improved in this study.A batch of sediment samples were put into centrifuge tubes,and continuously vibrated in a constant temperature bath oscillator.Contents of biogenic silica（BSi） of the extracted samples were measured every hour through wet-alkaline extraction procedure.The optimum extraction condition was obtained with the linear regression method.Samples were then extracted with the single-point extraction method under the optimum condition,and the content of BSi was measured with silicon-molybdenum blue method.This method had rapid speed of single point extraction in determining BSi,and also reduced the volume errors from multi-point method.In this paper,variation of biogenic silica content of reservoir sediments in the Wujiang Drainage Basin,and their environmental implications were also discussed.