使用乙炔抑制法对上海市苏州河以及崇明岛河流沉积物的反硝化速率进行测定，同时测定沉积物提取态硝酸盐和铵态氮含量、有机碳含量、容重、含水率以及上覆水的相关理化指标。结果表明，苏州河表层10 cm深度单位面积沉积物的反硝化速率为126�22μg·m－2·h－1，是崇明岛河流沉积物反硝化速率（105�57μg·m－2·h－1）的1�2倍，城市区域污染河流沉积物的反硝化速率明显高于农村清洁河流。苏州河0～10 cm深度沉积物的反硝化速率在0�15～5�07 ng·g－1·h－1之间，崇明岛河流0～10 cm深度沉积物的反硝化速率在0�39～2�80 ng·g－1· h－1之间，且反硝化速率均表现出随着深度增加而降低的变化特征。对各环境因子与沉积物反硝化速率进行相关性分析发现，沉积物提取态硝酸盐含量与反硝化速率呈显著正相关（苏州河：r＝0�699，P＜0�05；崇明岛河流：r＝0�629，P＜0�05），是影响沉积物反硝化过程的主要因素。%Denitrification rates in the sediments of the Suzhou River and the rivers in Chongming Island of Shanghai were measured with the acetylene inhibition method. Extractable NO3-and NH4+, sediment organic carbon ( SOC) , bulk densi⁃ty, moisture content of the sediments, and relevant physicochemical properties of their overlying waters were also deter⁃mined. Results show that the denitrification rate in the top 10 cm sediment of the Suzhou River is 126�22μg·m-2 ·h-1 , 1�2 times higher than that in the rivers in the Chongming Island ( 105�57μg·m-2 ·h-1 ) . Obviously it is much higher in the sediment of a seriously polluted river running through the urban area than in the sediment of a less polluted rural river. Denitrification rate in the sediments varied with sediment depth ( 0-10 cm) , ranging from 0�15 to 5�07 ng·g-1 ·h-1 in the Suzhou River, and from 0�39 to 2�80 ng·g-1 ·h-1 in the rivers in the Chongming Island, and decreased with the in⁃creasing depth. Correlation analysis of sediment denitrification rate with environmental factors demonstrates that the denitri⁃fication rate was positively related to extractable NO3-⁃N in the sediment ( Suzhou River:r=0�699, P<0�05;Chongming Island rivers:r=0�629, P<0�05) . So extractable NO3-⁃N is the key factor influencing sediment denitrification rate in the sediment.
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