黄河表层沉积物中磷形态分布与释放风险

Distribution of phosphorus species and their release risks in the surface sediments from different reaches along Yellow River

研究了黄河干流表层沉积物中磷形态分布特征、释放风险以及人工筑坝给黄河磷循环带来的影响.研究结果表明,黄河表层沉积物中钙磷(P_(Ca))含量较高,生物可利用磷(BP)[BP=可交换态磷(P_(ex))+铝结合态磷(P_(Al))+铁结合态磷(P_(Fe))]含量较低,在全程21个站位表层沉积物样品W(BP)/W(P_(Ca))的比值中,仅有大禹渡段(H_(15))高于0.5,表明H15磷释放强度较大,具有潜在的水体富营养化发生的风险,而黄河其他河段水体沉积物磷释放水平较低;全程表层沉积物样品中BP含量和总磷(∑P)含量由高到低的顺序为:黄河中游和上游>下游,而上覆水中总磷(TP)含量由高到低的顺序为:黄河下游>中游和上游(除H_7段),说明黄河流域广泛的人工筑坝,导致其上覆水从上游到下游的TP浓度明显升高,而黄河海勃湾水利枢纽工程的建立使得乌海段H_7总颗粒物(TMP)浓度降到极低点,上覆水中的磷浓度高达到0.1361 mg·L^(-1).

We investigated the distribution of P species and their release risk in the surface sediments from different reaches along Yellow River, as well as the influence of artificial dam on phosphorus cycle in Yellow River. The results show that the content of calcium phosphorus（PCa） is higher than the content of bioavailable phosphorus（BP）（BP=Pex＋PAl＋PFe, in formula Pex means exchangeable phosphorus, PAl means aluminum phosphorus, PFe means iron phosphorus） in the surface sediments from Yellow River. Among all the surface sediment samples from 21 stations, only Da Yu Du section（H15） has a ratio of W（BP）/W（PCa） higher than 0.5, plying potentially higher intensity of reused P of the sediment of H15, and eutrophication risk in water.Yet the phosphorus release from the sediment of the other reach of Yellow River is low. The content of BP and total phosphorus（∑P）in the surface sediments along Yellow River are in the descending order：middle reaches of Yellow River and upper reaches of Yellow River〉Yellow River downstream, while the content of total phosphorus（TP） in the overlying water is in the following order：Yellow River downstream〉middle reaches of Yellow River and upper reaches of Yellow River（except the H7 station）, indicating that with extensive artificial damming in Yellow River basin, the concentration of TP increased significantly in overlying from upstream to downstream. The establishment of Hai Bo Wan water conservancy project in Yellow River reduced the total particulate matter（TMP） concentration in the water to very low lever in Wuhai H7 section, and the phosphorus concentration in the overlying water reached：0.1361 mg·L^-1.