天津市不同污染特征典型河流沉积物反硝化对比研究

使用乙炔抑制法对天津市不同污染特征代表性的城市内河南运河、北塘排污河以及城郊东丽区自然河流底部沉积物的反硝化速率和潜力及其冬(3月)夏(8月)季节变化进行了测定。结果表明:1)夏、冬两季天津市不同污染特征的河流沉积物反硝化速率存在着显著的空间差异(p0.05)。夏季排污河沉积物的反硝化速率明显高于较清洁河流,而冬季相反;2)就全年数据来看,各河流沉积物夏季反硝化速率高于冬季,其中北塘排污河表现出最大的季节差异;3)北塘排污河沉积物相较另外两条河流具有较高的反硝化潜力;4)各样点河流沉积物反硝化速率及潜力基本表现为随深度的增加而降低。相关性分析发现河流沉积物反硝化速率与有机碳呈显著正相关(p0.05),因此天津市不同类型河流沉积物有机碳或是影响反硝化过程,导致时空差异的重要因素。天津市河流沉积物反硝化潜力是反硝化速率的1.50~22.8倍,且排污河沉积物脱氮潜力较清洁河流大。

Comparative Study on Denitrification of Typical River Sediments under Different Pollution Characteristics in Tianjin City, China

Acetylene inhibition method was used to measure denitrification rate, potential and their seasonal changes(March and August) in three typical river sediments, which are Nanyun in downtown, Beitang sewage-received river and natural river Dongli in suburban, and they have different pollution characteristics. Results show that (1) denitrification rates of Tianjin river sediments with different pollution characteristics have significant spatial differences (p<0.05) between summer and winter. Denitrification rate of the sewage-received river sediment is significantly higher than other two rivers in summer, but on the contrary, the lowest in winter; (2) based on the full year data, sediment denitrification rates in each river in summer are higher than winter, and Beitang sewage-received river shows the greatest seasonal variation; (3) Beitang sewage-received rive sediment has higher denitrification potential compared with other two rivers; and (4) denitrification rate and potential decrease with increasing depth of the sediment in three rivers. By using factors correlation analysis, sediment organic carbon, in different types of rivers in Tianjin, may be a significant factor influencing denitrification process, leading to variations in seasons and space. Sediment denitrification rate has a significant positive correlation(p<0.05) with sediment organic carbon. Denitrification potential is 1.50 to 22.8 times higher than denitrification rate in sediment, and denitrification potential in the sewage-received river sediment is higher compared with other clean rivers.