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(NO^(-)_(3)-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),NO^(-)_(3)-N大量分布在深度0~240 cm的土壤中(p<0.05),部分NO^(-)_(3)-N下渗进入地下水,高施肥量采样点地下水中NO^(-)_(3)-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NO^(-)_(3)-N的主要来源.铵态氮(NH^(+)_(4)-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NH^(+)_(4)-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NH^(+)_(4)-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NH^(+)_(4)-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.
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 NO^(-)_(3)-N and DON contents were significantly higher in the soil of sampling sites with higher fertilization rates. NO^(-)_(3)-N accumulated mainly within the soils at depths of 0~240 cm(p<0.05). Part of the NO^(-)_(3)-N infiltrated into the groundwater, resulting in the highNO^(-)_(3)-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 NO^(-)_(3)-N in the groundwater of this area. Furthermore, NH^(+)_(4)-N was mainly distributed at depths of 0~240 cm and 400~460 cm(p<0.05) in the unsaturated zone. The NH^(+)_(4)-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 NH^(+)_(4)-N in groundwater, but was also likely to be a main cause for the high accumulation of NH^(+)_(4)-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.
作者
董杰
申泽良
管勇
尹政
王建收
辛佳
DONG Jie;SHEN Zeliang;GUAN Yong;YIN Zheng;WANG Jianshou;XIN Jia(Qingdao Geo-Engineering Surveying Institute(Qingdao Geological Exploration and Development Bureau),Qingdao 266071;Key Laboratory of Urban Geology and Underground Space Resources,Shandong Provincial Bureau of Geology and Mineral Resources,Qingdao 266071;Qingdao Geology and Geotechnical Engineering Co.,Ltd,Qingdao 266071;Key Lab of Marine Environment and Ecology,Ministry of Education,Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering,College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100)
出处
《环境科学学报》
CAS
CSCD
北大核心
2021年第4期1496-1510,共15页
Acta Scientiae Circumstantiae
基金
国家自然科学基金重点项目(No.41731280)。
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
nitrogen distribution
landfill leachate
nitrogen fertilizer
the unsaturated and saturated zone
nitrogen-cycling functional microorganisms
