Abstract：
Physicochemical and toxicological characterization of leather tanning wastewater has been widely documented. However, few reports have examined the response of denitrification N2 and N2O emissions in riparian sediments of tannery wastewater-receiving rivers. In this study, 15N-nitrate labeling was used to reveal the effects of tanning wastewater on denitrification N2 and N2O emission in a wastewater-receiving river (the old Mang River, OMR). OMR riparian sediments were highly polluted with total organic carbon (93.39 mg/kg), total nitrogen (5.00 g/kg) and heavy metals; specifically, Cr, Zn, Cd, and Pb were found at concentrations 47.3, 5.8, 1.6, 4.3, and 2.8 times that in a nearby parallel river without tanning wastewater input (the new Mang River, NMR), respectively. The denitrification N2 emission rates (0.0015 nmol N · g-1 h-1) of OMR riparian sediments were significantly reduced by 2.5 times compared with those from the NMR (p < 0.05), but the N2O emission rates (0.31 nmol N · g-1 h-1) were significantly increased (4.1 times, p < 0.05). Although the dominant nitrogen-transforming bacteria phylum was Proteobacteria in the riparian sediments of both rivers, 11 nitrogen-transforming bacteria genera in the OMR were found to be significantly enriched; five of these were related to pollutant degradation based on linear discriminant analysis (LDA >3). The average activity of the electron transport system in the OMR was 6.3 times lower than that of the NMR (p < 0.05). Among pollution factors, heavy metal complex pollution was the dominant factor driving variations in N2O emissions, microbial community structure, and electron transport system activity. These results provide a new understanding and reference for the treatment of tanning wastewater-receiving rivers.
摘要：
皮革制革废水的物理化学和毒理学表征已被广泛记录。然而,很少有报告研究了制革废水接收河流河岸沉积物中反硝化N2和N2O排放的响应。在这项研究中,15N-硝酸盐标记用于揭示鞣制废水对废水接收河（老芒河，OMR）。OMR河岸沉积物受到总有机碳（93.39mg/kg）的高度污染，总氮(5.00克/千克)和重金属；特别是，Cr,Zn,Cd,和Pb的浓度分别是附近一条没有鞣制废水输入的平行河流的47.3、5.8、1.6、4.3和2.8倍（新的芒河，NMR),分别。OMR河岸沉积物的反硝化N2排放速率（0.0015nmolN·g-1·h-1）与NMR相比显着降低了2.5倍（p<0.05），但是N2O的排放速率（0.31nmolN·g-1·h-1）显着增加（4.1倍，p<0.05)。尽管两河河岸沉积物中优势的氮转化细菌门是变形杆菌，发现OMR中的11个氮转化细菌属显著富集；基于线性判别分析（LDA>3），其中5个与污染物降解有关。OMR中电子传输系统的平均活性比NMR低6.3倍(p<0.05)。在污染因素中，重金属复合污染是驱动N2O排放变化的主要因素，微生物群落结构,和电子传输系统活动。这些结果为制革废水受纳河流的处理提供了新的认识和参考。
