Li Ru-Zhong, Zheng Xia, Gao Su-di, Ye Zou
School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
College of Civil and Environmental Engineering, Anhui Xinhua University, Hefei 230031, China.
Huan Jing Ke Xue. 2017 Nov 8;38(11):4598-4606. doi: 10.13227/j.hjkx.201704201.
Water and benthic sediment samples were collected monthly from six sites over a 2-km reach in a first-order stream located in the northeastern rural-urban fringe of Hefei City, from May 2016 to January 2017. These sites were scattered in three stream reach types as natural pattern sections (Scenario 1), point source pollution sections (Scenario 2), and severe soil erosion sections (Scenario 3). The potential rates of nitrification and denitrification in the sediments were measured and variable characteristics were evaluated quarterly. Moreover, a difference analysis of each of the three scenarios and an influencing factor analysis for nitrification and denitrification potentials were subsequently conducted. Our results show that:① the mean value of the nitration ratios for total sediment samples is 0.381%, of which the maximum nitration ratio emerged in Scenario 2. As for Scenario 1, the nitration ratio in summer is the larger than in winter. The nitration ratios for Scenarios 2 and 3 rank from largest to smallest as spring > summer > autumn > winter. ② The mean value of the nitrification rate of the total sediment samples is 0.364 mg·(kg·d), of which the maximum nitrification rate is associated with in Scenario 2. The nitrification rate is highest in winter, while similar for all other seasons in Scenarios 2 and 3. There is not much difference all year round for Scenario 1. ③ Average values for the denitrification ratio and denitrification rate for all sediment samples are 37.25% and 57.68 mg·(kg·d), respectively. Both of these are higher for Scenario 2 than the other two scenarios for the same season. The ranking for denitrification for Scenarios 1 and 2 is summer > spring > autumn > winter, and spring > summer > autumn > winter in Scenario 3. ④ According to the difference analysis, significant differences not only exist between the nitrification rates between Scenarios 1 and 2 but also for the denitrification ratios and denitrification rates between Scenarios 1 and 3. In addition, there is an obvious difference in the nitration ratio between Scenarios 2 and 3. ⑤ Partial least-squares regressive analysis indicates that there is significant difference between the important influencing factors related to the nitration ratio and nitrification rate for each of the three scenarios.
2016年5月至2017年1月期间，每月从合肥市东北城乡结合部一条一级溪流2公里河段内的六个地点采集水和底栖沉积物样本。这些地点分布在三种河段类型中，分别为自然形态段（情景1）、点源污染段（情景2）和严重水土流失段（情景3）。对沉积物中的硝化和反硝化潜在速率进行了测量，并每季度评估其变化特征。此外，随后对三种情景中的每一种进行了差异分析，并对硝化和反硝化潜力的影响因素进行了分析。我们的结果表明：① 所有沉积物样本的硝化率平均值为0.381%，其中最大硝化率出现在情景2中。对于情景1，夏季的硝化率大于冬季。情景2和情景3的硝化率从大到小依次为春季>夏季>秋季>冬季。② 所有沉积物样本的硝化速率平均值为0.364 mg·(kg·d)，其中最大硝化速率与情景2相关。硝化速率在冬季最高，而情景2和情景3中其他季节的硝化速率相似。情景全年变化不大。③ 所有沉积物样本的反硝化率和反硝化速率平均值分别为37.25%和57.68 mg·(kg·d)。在同一季节，情景2中的这两个值均高于其他两种情景。情景1和情景2的反硝化排序为夏季>春季>秋季>冬季，情景3为春季>夏季>秋季>冬季。④ 根据差异分析，情景1和情景2之间的硝化速率、情景1和情景3之间的反硝化率和反硝化速率均存在显著差异。此外，情景2和情景3之间的硝化率也存在明显差异。⑤ 偏最小二乘回归分析表明，三种情景中与硝化率和硝化速率相关的重要影响因素之间存在显著差异。
