Hebei and China Geological Survey Key Laboratory of Groundwater Remediation, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China.
Hebei and China Geological Survey Key Laboratory of Groundwater Remediation, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China.
J Environ Sci (China). 2020 Mar;89:9-22. doi: 10.1016/j.jes.2019.09.021. Epub 2019 Nov 5.
A multi-isotope approach and mixing model were combined to identify spatial and seasonal variations of sources, and their proportional contribution to nitrate in the Hutuo River alluvial-pluvial fan region. The results showed that the NO concentration was significantly higher in the Hutuo River valley plain (178.7 mg/L) region than that in the upper and central pluvial fans of the Hutuo River (82.1 mg/L and 71.0 mg/L, respectively) and in the river (17.0 mg/L). Different land use types had no significant effect on the groundwater nitrate concentration. Based on a multi-isotope approach, we confirmed that the main sources of groundwater nitrate in different land use areas were domestic sewage and manure, followed by soil nitrogen, ammonia fertilizer, nitrate fertilizer and rainwater, and there were no significant spatial or seasonal variations. Combining δN-NO, δO-NO and δCl results can increase the accuracy of traceability. Nitrification could be the most important nitrogen migration and transformation process, and denitrification did not significantly affected the isotopic composition of the nitrate. The SIAR model outputs revealed that the main nitrate pollution sources in groundwater and river water were domestic sewage and manure, accounting for 55.9%-61.0% and 22.6% (dry season), 50.3%-60.4% and 34.1% (transition season), 42.7%-47.6% and 35.6% (wet season 2016) and 45.9%-46.7% and 38.4% (wet season 2017), respectively. This work suggests that the random discharge and disposal of domestic sewage and manure should be the first target for control in order to prevent further nitrate contamination of the water environment.
采用多同位素示踪与混合模型相结合的方法，识别硝酸盐的来源及其空间和季节性变化，以及它们对滏阳河冲积扇区硝酸盐的相对贡献。结果表明，与滏阳河上游和中部洪积扇（82.1mg/L 和 71.0mg/L）以及河流（17.0mg/L）相比，滏阳河河谷平原（178.7mg/L）地区的硝酸盐浓度显著较高。不同的土地利用类型对地下水硝酸盐浓度没有显著影响。基于多同位素示踪方法，我们确认了不同土地利用区地下水硝酸盐的主要来源是生活污水和粪便，其次是土壤氮、氨肥、硝酸盐肥和雨水，且不存在明显的空间或季节性变化。结合δN-NO、δO-NO 和 δCl 的结果可以提高溯源的准确性。硝化作用可能是最重要的氮迁移和转化过程，反硝化作用对硝酸盐的同位素组成没有显著影响。SIAR 模型输出结果表明，地下水和河水中硝酸盐的主要污染源是生活污水和粪便，分别占枯水期（55.9%-61.0%和 22.6%）、过渡季（50.3%-60.4%和 34.1%）、丰水期 2016（42.7%-47.6%和 35.6%）和丰水期 2017（45.9%-46.7%和 38.4%）的 55.9%-61.0%和 22.6%、50.3%-60.4%和 34.1%、42.7%-47.6%和 35.6%、45.9%-46.7%和 38.4%。本研究表明，应将生活污水和粪便的随意排放和处置作为控制的首要目标，以防止水环境中硝酸盐的进一步污染。
