洋河水库流域土壤与库区沉积物中磷形态特征研究

应用SMT法研究了洋河水库流域土壤、河道及库区沉积物中总磷(TP)、无机磷(IP)、有机磷(OP)、铁/铝磷(Fe/Al-P)、钙磷(Ca-P)等5种形态,分析了不同区域各形态磷的分布特征.结果表明,洋河水库流域土壤、沉积物中TP、总氮(TN)和有机质(OM)的均值含量总体变化趋势为河道>库区>土壤,其中TP含量变化不大,这说明营养盐不仅通过土壤径流、河道迁移进入库区,而且库区沉积物的释放作用同样明显.库区柱状沉积物有明显的“表层富积”现象,随着沉积物深度的增加,TP、TN和OM含量逐渐减少,在0~16cm下降趋势明显,16cm以下基本保持不变,说明库区沉积物主要以表层污染为主.土壤、沉积物中的磷以IP为主,大约占TP的46%~79%之间,且研究区各磷形态中以Ca-P为主,大约占TP的22%~68%,这与库区地质—地球化学特征有关.土壤中TP的增加主要来自于Ca-P,与该地区土壤的地质背景有关,河道沉积物中TP的增加主要来自于Fe/Al-P,即河道受到人类活动污染的影响较大,而库区TP的增加主要来自于OP,说明洋河水库的富营养化与流域的工业、生活污染以及农业面源污染有关.

Distribution characteristics of phosphorus in sediment of Yanghe Reservoir and in soil of its basin

Total phosphorus (TP), inorganic-phosphorus (IP), organic-phosphorus (OP), Fe/Al-bound phosphorus (Fe/Al- P) and Ca-bound phosphorus (Ca- P) in sediments of Yanghe Reservoir and in soil of its basin were measured using the standard measurement and test (SMT) procedure. The general mean content variation trends of total phosphorus (TP), total nitrogen (TN) and organic matter (OM) in the soil and sediments were stream sediments> reservoir sediments>soil, while the TP mean content changed little during the migration process. Nutrients enter Yanghe Reservoir not only by soil runoff and stream migration, but also the role of sediment release is obvious. The nutrients contents in surface sediment were high according the results of the column sediments, and the contents of TP, TN and OM decreased with the increase of sediment depth from the surface to 16cm, and then held on line below 16cm, which indicated that nitrogen and phosphorus pollution in the sediments was primarily on the surface. The IP was the major phosphorus species in the soil and sediments, which accounted for 46%~79% of the TP; and the Ca-P was the major phosphorus species in the study area, and accounted for 22%~68% of TP, which related to the geological-geochemical characteristics of the Yanghe Reservoir. The TP in the soil was original mainly from Ca-P, which relate to the geological background in this region. The TP in sediment from the stream was original mainly from Fe/Al-P, which relate to the industrial and human pollution in this basin. The TP in sediment from Yanghe Reservoir was original mainly from the OP, which indicate that the eutrophication of Yanghe reservoir relates to the industrial, domestic pollution and agricultural non-point pollution in this basin.