Li Jing, Li Fadong, Liu Qiang, Suzuki Yoshimi
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing 100101, China.
Environ Sci Process Impacts. 2014 Dec;16(12):2764-73. doi: 10.1039/c4em00200h.
Irrigation projects have diverted water from the lower reaches of the Yellow River in China for more than 50 years and are unique in the world. This study investigated the effect of irrigation practices on the transfer and regional migration mechanisms of nitrate (NO3(-)) in surface water and groundwater in a Yellow River alluvial fan. Hydrochemical indices (EC, pH, Na(+), K(+), Mg(2+), Ca(2+), Cl(-), SO4(2-), and HCO(3-)) and stable isotopic composition (δ18O and δD) were determined for samples. Correlation analysis and principal component analysis (PCA) were performed to identify the sources of water constituents. Kriging was employed to simulate the spatial diffusion of NO3(-) and stable isotopes. Our results demonstrated that the groundwater exhibited more complex saline conditions than the surface water, likely resulting from alkaline conditions and lixiviation. NO3(-) was detected in all samples, 87.0% of which were influenced by anthropogenic activity. The NO3(-) pollution in groundwater was more serious than the common groundwater irrigation areas in the North China Plain (NCP), and was also slightly higher than that in surface water in the study area, but this was not statistically significant (p > 0.05). In addition, the groundwater sites with higher NO3(-) concentrations did not overlap with the spatial distribution of fertilizer consumption, especially in the central and western parts of the study area. NO3(-) distributions along the hydrogeological cross-sections were related to the groundwater flow system. Hydrochemical and environmental isotopic evidences indicate that surface water-groundwater interactions influence the spatial distribution of NO3(-) in the Piedmont of South Taihang Mountains.
五十多年来，中国的灌溉工程一直从黄河下游调水，这在世界上是独一无二的。本研究调查了灌溉措施对黄河冲积扇地表水和地下水中硝酸盐（NO3(-)）迁移及区域运移机制的影响。测定了水样的水化学指标（电导率、pH值、Na(+)、K(+)、Mg(2+)、Ca(2+)、Cl(-)、SO4(2-)和HCO(3-)）以及稳定同位素组成（δ18O和δD）。通过相关性分析和主成分分析（PCA）确定水体成分的来源。采用克里金法模拟NO3(-)和稳定同位素的空间扩散。我们的结果表明，地下水的盐分状况比地表水更为复杂，这可能是由碱性条件和淋溶作用导致的。所有样品中均检测到NO3(-)，其中87.0%受人为活动影响。研究区地下水中NO3(-)污染比华北平原（NCP）普通的地下水灌溉区更为严重，且略高于地表水，但差异无统计学意义（p>0.05）。此外，NO3(-)浓度较高的地下水采样点与化肥施用量的空间分布并不重叠，尤其是在研究区的中西部地区。沿水文地质剖面的NO3(-)分布与地下水流系统有关。水化学和环境同位素证据表明，地表水与地下水的相互作用影响了南太行山山前地带NO3(-)的空间分布。
