Retention of nitrogen and phosphorus in Wan'an Reservoir, Jiangxi Province

Abstract

以江西省万安水库为研究对象, 于2007-2009年丰、枯水期对水库进行了入库、出库水样采集, 研究了万安水库对氮、磷营养盐的滞留效应.结果表明, 万安水库对氮、磷营养盐存在显著滞留作用.DIN浓度和输送通量整体均表现为入库>出库, 受径流量季节变化的影响, 不同时期DIN的滞留情况整体表现为枯水期<丰水期;TP浓度和输送通量整体均表现为入库>出库, 不同时期的浓度滞留情况整体表现为枯水期>丰水期.2007-2009年问分别有1.57×10⁴t、2.38×10⁴t、2.95×10⁴t溶解态氮滞留于万安水库, 2007年和2009年分别有7.44×10²t、3.65×10³t的总磷滞留于库内, 2008年万安水库对总磷出现负滞留, 其原因与外源输入作用、水库的运行方式以及低水位时内源释放作用有关.溶解态氮的滞留效率在12%-45%范围内变化, 年平均值为32.0%;总磷的滞留效率在-89%至80%范围内变化, 氮、磷营养盐的滞留效率满足磷>氮.径流量是引起水库溶解态氮输送通量季节变化的主要影响因子, 浓度是制约磷营养盐滞留的主要因素。;The effects on the total nitrogen (TN) and total phosphorus (TP) retention of the inflows and outflows in Wan'an Reservoir, Jiangxi Province were investigated from 2007 to 2009.The results indicated that 1.57×lO⁴, 2.38×lO⁴ and 2.95×lO⁴ tons of dissolved nitrogen were trapped in Wan'an Reservoir in 2007, 2008 and 2009 respectively, and 7.44×10² t, 3.65×lO³ t of TP in 2007 and 2009, respectively.The retention of TP in Wan'an Reservoir appeared negative in 2008, which reflected exogenous input.The retention efficiencies of dissolved nitrogen were the annual average of 32% with the range of 12%-45%, and retention efficiencies of TP were in the range of-89% to 80%.It suggested that the retention efficiency of nitrogen was lower than that of phosphorus except for 2008.The river runoff was the main factor of the seasonal changes of TN fluxes, and the nutrient concentra-tion was the restriction factor on the retention of TP.