河套灌区沟渠表层沉积物对磷的吸附

为了解北方干旱灌区沟渠沉积物在磷的迁移转化中的作用，该文以河套灌区解放闸灌域总干渠、黄济干渠、总排干和二排干为研究对象，分别在上、中、下3个位点采集上覆水和沉积物，测定水样溶解性磷和总磷含量，对沉积物磷的形态进行分析，选择部分沉积物进行吸附动力学试验和等温吸附试验。结果表明，总干渠、黄济干渠和总排干、二排干水体磷含量相近，沉积物各形态的磷含量一般为钙结合态磷＞残渣磷＞闭蓄态磷＞铝结合态磷＞弱结合态磷＞铁结合态磷，弱结合态磷、铁结合态磷和铝结合态磷高活性磷含量低且显著正相关。研究表明，沟渠对河套灌区磷输出有削减作用，且沟渠沉积物磷释放风险高，总排干、二排干沉积物较总干渠、黄济干渠沉积物磷吸附容量大。

Phosphorus adsorption on the surface sediments of ditches in Hetao irrigation

In order to understand the role of sediments in the phosphorus transformation in the north China. Overlying water and surface sediments samples were took from up, middle and down sample sites of Main canal, Huangji Tributary canal, Main drainage ditch and Second tributary drainage ditch. Then the concentration of soluble phosphorus and total phosphorus of overlying water were determined and the phosphorus fractions of sediments were analyzed. Moreover, adsorption kinetic and adsorption isotherm of the sediments were obtained. It found that phosphorus in the drainage ditch did not raised obviously. The content of phosphorus fractions ranged sequentially Calcium bound phosphorus > Residual phosphorus > Reductant Soluble phosphorus > Aluminum bound phosphorus > Soluble and Loosely bound phosphorus > Iron bound phosphorus. Especially, the content of Soluble and Loosely bound phosphorus, Iron bound phosphorus and Aluminum bound phosphorus, which were easy to release to water, were very low and they were positively correlative with each other. It conclude that ditches are helpful in the phosphorus reduction, the risk of releasing phosphorus form sediment is high and the adsorption capacity of drainage ditch sediments is larger than that of canal sediments.