| 两种PPCPs对雅鲁藏布江沉积物硝化作用的影响 |
| 摘要点击 1876 全文点击 648 投稿时间：2020-11-23 修订日期：2020-12-02 |
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| 中文关键词 磺胺甲唑 甲氧基肉桂酸乙基己酯 雅鲁藏布江 沉积物 硝化作用 |
| 英文关键词 sulfamethoxazole 2-ethylhexyl-4-methoxycinnamate Yarlung Zangbo River sediment nitrification |
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| 中文摘要 |
| 为了掌握药物及个人护理用品（pharmaceuticals and personal care products，PPCPs）对高海拔河流氮转化过程的影响，采用沉积物泥浆实验方法，研究了磺胺甲唑（sulfamethoxazole，SMX）和甲氧基肉桂酸乙基己酯（2-ethylhexyl-4-methoxycinnamate，EHMC）在不同浓度下（0.01、0.1、1.0、10和100 μg·L-1）对雅鲁藏布江沉积物硝化作用的影响.所有处理组均显著降低了硝化速率，SMX和EHMC共暴露诱导了最大抑制率，达到66%.所有SMX和EHMC处理组均显著抑制了氨单加氧酶（ammonia monooxygenase，AMO）活性和amoA基因丰度，SMX单独及其与EHMC联合诱导了比EHMC更强的抑制效应.SMX单独或与EHMC联合暴露显著抑制了沉积物中的羟胺氧化酶（hydroxylamine oxidase，HAO）活性及hao基因丰度，共暴露的抑制效应更强，而单独EHMC处理增加了HAO活性和hao基因丰度.结果表明，PPCPs影响了高海拔河流沉积物中硝化菌群的活性，抑制了硝化过程，联合暴露进一步增加了水生态系统中氮负荷压力. |
| 英文摘要 |
| To understand the effects of pharmaceuticals and personal care products (PPCPs) on nitrogen transformation in high-altitude rivers, we investigated the influence of the single and combined exposure of sulfamethoxazole (SMX) and 2-ethylhexyl-4-methoxycinnamate (EHMC) at different concentrations (0.01, 0.1, 1.0, 10, and 100 μg·L-1) on nitrification in the sediments of the Yarlung Zangbo River in sediment slurry experiments. All treatments significantly reduced nitrification rates, and the maximum inhibition rates induced by SMX and EHMC (alone and in combination) were 47%, 50%, and 66%, respectively. SMX significantly inhibited ammonia monooxygenase (AMO) activity in a concentration-dependent manner, with the inhibition rates ranging from 51% to 78%. The inhibitory effect of SMX combined with EHMC on AMO activity was similar to or stronger than that of SMX alone, and the inhibition rates ranged from 55% to 84%. All EHMC exposures also significantly inhibited AMO activity, but the inhibition rates decreased with an increase in EHMC concentrations. The amoA gene abundance was significantly reduced in all the treatments, and SMX alone and in combination with EHMC induced stronger inhibitory effects than EHMC alone. SMX alone and in combination with EHMC significantly inhibited HAO activity, showing a similar concentration-effect relationship, but their combined exposure produced a stronger effect. SMX alone and in combination with EHMC also significantly decreased hao gene abundance in the sediments, and the maximum inhibition rates were 76% and 68%, respectively. Although exposure to higher concentrations of EHMC increased hao gene abundance and HAO activity, the notable decrease in nitrification rates in the sediments suggested that oxidation of ammonia to hydroxylamine catalyzed by AMO was the rate-limiting step in the nitrification process. The results also showed that PPCPs influence the activities of nitrifying communities in the sediments of high-altitude rivers and inhibit nitrification, and their coexistence further increases the pressure of nitrogen loading in aquatic ecosystems. |
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