摘要:华北平原地下水硝酸盐污染备受关注，然而受地貌类型、土地利用、土壤结构、含水层水文地质条件等因素差异性的影响，对区域尺度上农区浅层地下水硝酸盐污染程度和特征尚没有统一定论。本文通过综述过去华北平原地下水硝酸盐污染程度的相关研究，并结合近年来对华北平原农业种植区浅层地下水硝酸盐研究所取得的认识，指出补给源区（太行山低山丘陵区）、山前平原和低平原3个典型地貌类型区浅层地下水硝酸盐研究存在的问题：补给源区土地利用变化多样、土壤和含水层渗透性好，要重视对源区氮输入的控制，加强低山丘陵区气候变化对水文过程和氮迁移过程影响机制的研究；山前平原区是农业高产区，地下水埋深较深且包气带厚度大，较高的浅层地下水硝酸盐浓度除了与点源、污水渗漏以及污水灌溉等直接影响因素有关外，农田过量肥料施用对地下水硝酸盐影响的程度、水氮迁移路径以及未来潜在风险是农区地下水硝酸盐研究中亟需关注的问题；低平原区较细的土壤沉积结构减缓了氮向下迁移的速度，但地下水埋深较浅，二者的制约关系决定了地下水硝酸盐浓度，因此应在理解地表水-土壤-地下水转化关系的基础上评估地下水硝酸盐污染的风险。
关键词:地下水/
硝酸盐污染/
土地利用/
地貌类型/
包气带/
华北平原
Abstract:Nitrate contamination of groundwater in the North China Plain had attracted much attention. However, the characteristics and degree of nitrate contamination of groundwater on large scale were not uniform due to the effect of different factors such as landscape type, land-use, soil structure, and aquifer hydrogeology. This paper comprehensively summarized some studies on the status of nitrate pollution in groundwater in the North China Plain. It also included our results on nitrate concentration in shallow groundwater in agricultural areas in the North China Plain in recent years. It was found that nitrate pollution in shallow groundwater existed in three typical landscape types, including headwater area (hilly areas of Taihang Mountain), piedmont plain and lowland plain. The headwater area had different land-use and good soil and aquifer permeability and therefore required much attention in terms of controlling nitrogen input. There was also the need for researches on how climate change affected hydrological process and nitrogen transport in the region. The piedmont plain had high agricultural production, with deep groundwater depth and thick saturated zone. Relatively high nitrate concentration in the piedmont plain was not only related to point source, wastewater leakage and wastewater irrigation, but also to over application of fertilizer in the farmland. The impact of over application of fertilizer on groundwater, the flow path and the potential threat on shallow groundwater quality were very important for future researches. The leaching rate of nitrate was lowered due to the fine sediment of soil in the lowland area. However, groundwater was at high risk of nitrate contamination because of the shallow groundwater depth. There was therefore the need for correct assessment of potential risks of nitrate pollution of groundwater based on surface water, soil and groundwater interactions.
Key words:Groundwater/
Nitrate pollution/
Land use/
Landscape type/
Unsaturated zone/
North China Plain
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