• 关键词：氮素分布  垃圾渗滤液  氮肥  非饱和-饱和带  氮循环功能微生物

• 基金项目：国家自然科学基金重点项目（No.41731280）

• 董杰
• 1. 青岛地质工程勘察院(青岛地质勘查开发局), 青岛 266071;2. 山东省地矿局城市地质与地下空间资源重点实验室, 青岛 266071;3. 青岛地矿岩土工程有限公司, 青岛 266071

• 申泽良
• 中国海洋大学环境科学与工程学院, 海洋环境与生态教育部重点实验室, 山东省海洋环境地质工程重点实验室, 青岛 266100

• 管勇
• 1. 青岛地质工程勘察院(青岛地质勘查开发局), 青岛 266071;2. 山东省地矿局城市地质与地下空间资源重点实验室, 青岛 266071;3. 青岛地矿岩土工程有限公司, 青岛 266071

• 尹政
• 1. 青岛地质工程勘察院(青岛地质勘查开发局), 青岛 266071;2. 山东省地矿局城市地质与地下空间资源重点实验室, 青岛 266071;3. 青岛地矿岩土工程有限公司, 青岛 266071

• 王建收
• 1. 青岛地质工程勘察院(青岛地质勘查开发局), 青岛 266071;2. 山东省地矿局城市地质与地下空间资源重点实验室, 青岛 266071;3. 青岛地矿岩土工程有限公司, 青岛 266071

• 辛佳
• 中国海洋大学环境科学与工程学院, 海洋环境与生态教育部重点实验室, 山东省海洋环境地质工程重点实验室, 青岛 266100

• 摘要：农田氮肥和垃圾填埋场渗滤液是我国地下水氮素污染的两大来源，从氮肥-垃圾渗滤液复合影响区域内采集6份土壤剖面-地下水样品，分析非饱和-饱和带全剖面中氮素的分布特征，来清晰判识该类典型区域的氮素跨介质污染特征和途径，同时通过高通量测序进行氮循环功能微生物分析，来解析氮循环功能微生物对氮素分布的响应.结果发现，在高施肥量采样点中，土壤中的硝态氮（NO₃^--N）和溶解性有机氮（Dissolved Organic Nitrogen，DON）含量均显著高于低施肥量采样点（p<0.01），NO₃^--N大量分布在深度0~240 cm的土壤中（p<0.05），部分NO₃^--N下渗进入地下水，高施肥量采样点地下水中NO₃^--N浓度在总溶解性氮（Total Dissolved Nitrogen，TDN）中占比达31.93%~84.70%，硝化菌在氮循环功能菌中占比为27.08%~87.99%，说明氮肥是该区域地下水NO₃^--N的主要来源.铵态氮（NH₄⁺-N）在非饱和带深度0~20 cm和400~460 cm的范围内含量较高（p<0.05），垃圾填埋场下游的地下水NH₄⁺-N浓度均超标，在TDN中占比为26.40%~59.71%.统计分析表明，垃圾填埋场渗滤液可能是造成地下水中NH₄⁺-N浓度空间差异的重要因素，并很可能是导致地下水位波动带附近出现NH₄⁺-N高积累的主要原因（p<0.05）.这些结果将有助于复合影响区氮素的污染评估和防控.

• Abstract：In China, nitrogen fertilizer from agricultural lands and leachate from landfills are two main sources of nitrogen pollution in groundwater. In this paper, the study area was affected simultaneously by nitrogen fertilizer and landfill leachate. We collected both profile soil and groundwater samples from six sampling sites, in order to clearly identify the distribution characteristics and transport pathways of nitrogen in the vadose zone-groundwater system in such an area. In addition, the nitrogen-cycling functional microorganisms were also investigated using the high throughput sequencing method to clarify the response of nitrogen-cycling functional microorganisms to nitrogen distribution. The results showed that both NO₃^--N and DON contents were significantly higher in the soil of sampling sites with higher fertilization rates. NO₃^--N accumulated mainly within the soils at depths of 0~240 cm (p<0.05). Part of the NO₃^--N infiltrated into the groundwater, resulting in the highNO₃^--N levels(accounting for 31.93%~84.70% of TDN) and high nitrifying bacteria abundance (accounting for 27.08%~87.99% of nitrogen-cycling functional microorganisms) in groundwater at highly fertilized sites (p<0.01). This indicated that nitrogen fertilizer was the main source of NO₃^--N in the groundwater of this area. Furthermore, NH₄⁺-N was mainly distributed at depths of 0~240 cm and 400~460 cm (p<0.05) in the unsaturated zone. The NH₄⁺-N in the groundwater samples downstream of the landfill accounted for 26.40%~59.71% of the TDN concentrations, all exceeding the groundwater quality standard (GB/T 14848-2017). The landfill leachate was probably not only a significant contributor to the NH₄⁺-N in groundwater, but was also likely to be a main cause for the high accumulation of NH₄⁺-N (p<0.05) in deep soil near the groundwater table. These results would be helpful to assess and control nitrogen pollution from multiple sources.

• Key words：nitrogen distribution  landfill leachate  nitrogen fertilizer  the unsaturated and saturated zone  nitrogen-cycling functional microorganisms

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