In order to study the distribution characteristics of nitrogen in surface sediments from river,seven sites were selected for surface sediment sampling from the Xiaohe River to study two states nitrogen-ammonia and nitrate distribution characteristics and their relationship with organic mat-ter. The contents of ammonia nitrogen,nitrate nitrogen and organic matter in surface sediments were respectively measured by KCl digest-indophe-nol blue colorimetry,pbenoldisulfonic acid colorimetry and dichromate titration. Based on the results,single standard index method was used to e-valuate the pollution level of nitrogen in surface sediments. The results show that a)the total content of two states nitrogen in surface sediments from Xiaohe River is higher in the upstream section than that in the downstream section. In terms of two sections,the content of two states nitrogen is de-creased. They are affected by the contents of nitrogen and dissolved oxygen in water,oxidation-reduction potential of sediments and the degrada-tion of organic matter in sediments. The content of ammonia nitrogen is higher than nitrate nitrogen,the ratio of them is 1. 38,which indicates that the reduction level of the surface sediments in Xiaohe River is low. b)With regression analysis,the contents of nitrate nitrogen and organic matter show significant correlation. c)The content of total nitrogen is high,the standard index of over half of the sampling sites is more than one,which indicates that the environment quality of sediments in Xiaohe River polluted by nitrogen is relatively serious.%为了研究河道表层沉积物中氮素分布特征，以潇河为研究区，选取7个采样点，研究表层沉积物中两种形态的氮素———氨氮和硝酸盐氮，测定分析其含量、分布特征及成因，并探究其与有机质之间的关系。其中氨氮用KCl浸提－靛酚蓝比色法测定，硝酸盐氮用酚二磺酸比色法测定，沉积物中有机质的测定用重铬酸钾法。在测定结果的基础上，采用单项指标标准指数法对沉积物中氮的污染程度进行评价。结果表明：①潇河表层沉积物中氮素总量表现为中下游段高于中上游段的特征。就两个河流段而言，同时呈逐渐下降的趋势。氮素总量受到上覆水体氮营养盐水平、溶解氧含量及沉积物的氧化还原电位、沉积物中有机质的降解影响。氨氮含量大于硝酸盐氮，二者平均值之比为1．38∶1，表明潇河沉积物还原程度较低。②利用线性回归分析可知，沉积物中硝酸盐氮和有机质含量呈显著正相关。③潇河沉积物中总氮的含量较高，一半以上采样点的标准指数超过1，说明潇河沉积物环境质量受氮的污染相对严重。
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