【作者】 罗玉兰；

【导师】 徐颖；

【作者基本信息】 河海大学 ， 环境科学， 2007， 硕士

【摘要】 在一定条件下，内源氮磷可释放到水体中，加剧富营养化程度。因此，削减外源氮磷负荷后，控制内源氮磷负荷是控制水体富营养化的关键。本文以秦淮河沉积物为研究对象，结合河海大学水文水资源与水利工程科学国家重点实验室开放研究基金（2005408611），通过对沉积物和水样的分析测试，研究了城市内河沉积物营养盐的污染特征，采用室内模拟实验研究了环境因素对沉积物营养盐释放的影响，揭示了沉积物内源营养物释放规律，为秦淮河生态修复及城市内河科学疏浚提供依据。（1）沉积物间隙水的分层测定结果表明，间隙水中各营养盐指标含量均远高于上覆水体，尤其是氨氮含量。这表明水土界面存在很大的浓度梯度，有很强的释放趋势。内秦淮河沉积物间隙水中PO₄^3--P与TDP、Fe²⁺与PO₄^3--P之间相关程度较高，说明间隙水中TDP的变化主要受PO₄^3--P的影响，沉积物中磷的释放与沉积物氧化还原条件密切相关。（2）沉积物氮、磷形态的测定结果表明：内秦淮河沉积物总氮和总磷含量随着深度的增加呈逐渐减小的趋势，氮磷重量比为0.98～3.13，氮是秦淮河藻类生长的控制因素。沉积物中无机磷占总磷的比例为87％-97％，活性磷占总磷的比例为38％-43％，总氮与有机磷的相关性较好，表明两者在来源上具有一定的一致性。（3）疏浚深度对营养盐释放影响的试验结果表明：疏浚初期对沉积物磷的释放有一定的控制作用，但各断面出现释放速率显著下降所对应的疏浚深度有所不同，不同疏浚深度NH₄⁺-N释放速率差异较小。从长效而言，疏浚对秦淮河沉积物PO₄^3--P释放的控制效果较为明显，释放速率明显降低。（4）环境因子对沉积物氮、磷释放影响的试验结果表明：上覆水为蒸馏水时的释放速率大于河水为上覆水；光照不利于内源氮、磷的释放；扰动初期有利于氮、磷的释放，但当达到最大释氮、磷量后，释放强度不大甚至有所下降；温度升高促进沉积物中氮、磷的释放，随着释放的进行，各断面的NH₄⁺-N、TN释放速率随温度的升高明显下降；弱酸、弱碱性条件下底泥释磷量均高于中性条件；酸性条件NH₄⁺-N的释放率较高，随着上覆水pH的增加底泥NH₄⁺-N的释放速率降低；厌氧条件氮、磷释放量明显高于好氧条件。更多还原

【Abstract】 In certain condition, internal N and P can be released into water,which can sharpen eutrophication. Therefore internal N and P would play a key role in the river restoration after external N and P load reduction. Taking Qinhuai River sediment as the object, the paper studied the forms of internal N and P,the rule of release and the control measures in simulated laboratory conditions,which supported by State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University. Uses the modelling to study the existence shape of endogene nitrogen and phosphorus, the release rule and the control method, providing rests for the Qinhuai River ecology repair and the city inland river dredging sciencely.（1） The stratified interstitial water in sediment was monitored. The result indicated that each research target content in the body interstitial water is much higher than that of the rehydrate body, in particular ammonia nitrogen content. It indicated that there has the very strong release tendency for the very great concentration gradient between the water and soil contact surface. There was evident relativity between the total dissolved P and dissolved P in the porewater and between ferrous iron and the dissolved P. The higher degree of correlation indicates that the vary of the total dissolved P in porewater was mainly impacted on dissolved P and the release of P in sediment has intimate correlation with the condition of oxidation -reduction of sediment.（2） Different nitrogen and phosphorus forms in sediments were analyzed. The result indicated that the amount of TN and TP decreased with sediment depth,and the weight ratio between TN and TP is 0.98 to 3.13,so N is the control factor of alga in Qinhuai River. The proportion of inorganic P to TP in sediment is 87%～97%, and active P to TP is 38%～43%. There has good correlation between total nitrogen and organic phosphorus,which shows that they has some concordance of the source.（3） Statistical analysis of different dredging depth to nutrient release was measured .The result shows that it has some control to P release at the dredging beginning, but various cross sections appear scour the depth which the release speed remarkable drop corresponds to have differently. There is little difference of NH₄⁺-N release speed from different dredging depth. In a very long period of time,the control effect of dredging to PO₄^3--P release is obvious and the release speed obviously reduces.（4） Study on the release effects of environmental factors on N and P from urban channel sediments. The result indicated that the release ratio when the overlying water is distilled water is much higher than that of river water. Illumination is disadvantageous to the endogene N and the P release. Disturburance is advantageous to the endogene N and P release at the beginning,but the release intensity is smaller even has some declining when they reach maximal release. The release of N and P will be accelerated with higher temperature, and along with release carrying on, various cross sections NH₄⁺-N and TN release speed elevate along with the temperature obviously drops. Under the weak acid and weak basicity condition ,the bottom putty releases P quantity to be higher than the neutral condition, NH₄⁺-N release speed is upper under acid condition,and along with pH increase of the overling water, NH₄⁺-N release speed drops in the sediments. N and P release quantity obviously in anaerobic condition is higher than that of oxygen condition.更多还原