鄱阳湖沉积物有机磷累积特征及其与流域发展间的响应关系

选取了鄱阳湖4个柱状沉积物,应用改进的Hedley磷形态连续提取法和有机磷(OP)酶水解技术,研究了其OP累积特征、生物有效性变化及其与流域发展间的响应关系.结果表明:1自1972年以来,鄱阳湖沉积物OP含量呈持续增长趋势,其中南部湖区和"五河"尾闾区较北部和中部湖区增长趋势明显;不同阶段沉积物OP中H2O-Po和HCl-Po含量呈先下降,而近十年又有所增加趋势;Na OH-EDTA-Po含量则呈持续增长趋势,即鄱阳湖沉积物OP增加主要是由于Na OH-EDTA-Po的增加所致.2鄱阳湖沉积物各形态OP组成各异,其中H2O-Po含量较低,以类植酸磷为主,生物有效性较低;Na OH-EDTA-Po含量较高,以活性单酯磷为主,生物有效性较高.鄱阳湖沉积物OP增加主要来源于活性单酯磷,其生物有效性也呈增长趋势,二酯磷和类植酸磷则在1972—2002年间为下降趋势,2002年以来有所增加.3鄱阳湖沉积物OP,特别是Na OHEDTA-Po的累积主要受流域农业面源污染影响,其中沉积物OP和Na OH-EDTA-Po含量与流域单位面积磷肥施用量显著正相关,表明流域农业面源污染是导致鄱阳湖沉积物OP含量增加的重要原因之一.

Accumulation characteristics of organic phosphorus in sediments of Poyang Lake and its relationship with watershed development

To study the relationship among the organic phosphorus (OP) accumulation, bioavailability of OP and watershed development, four representative columnar sediment in Poyang Lake were investigated with the modified Hedley sequential extraction methods and enzymatic hydrolysis technique. Results show that: 1 in the sediment of Poyang lake, the OP content has been increasing continuously since 1972, and increased faster in the south and estuary of 'five rivers' than in the north and central area; H₂O-P_o and HCl-P_o content decreased first, but then increased in the last decade; the NaOH-EDTA-P_o content kept increasing with time, indicating that NaOH-EDTA-P_o was the main source of the OP. 2 The contents of different from of OP varied greatly, among which H₂O-P_o mainly consisted of phytate-like P, and its concentration and bioavailability were both in low level; the concentration and bioavailability of NaOH-EDTA-P_o, mainly consists of labile monoester P, are higher than H₂O-P_o . The increase of OP, together with its bioavailability in Poyang Lake sediment mainly caused by labile monoester P. the diester P and phytate-like P decreased from 1972 to 2002, but they have been increasing since 2002. 3 The accumulation of OP, especially NaOH-EDTA-P_o was influenced by agricultural non-Point source pollution. OP and NaOH-EDTA-P_o contents were positively correlated with phosphate fertilizer consumption per hectare in watershed of Poyang Lake, indicating that agricultural non-Point source pollution was an important cause for the increase of OP content in Poyang Lake sediment.