Dual-isotope-based source apportionment of nitrate in 30 rivers draining into the Bohai Sea, north China.
Dual-isotope-based source apportionment of nitrate in 30 rivers draining into the Bohai Sea, north China.
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DOI：
10.1016/j.envpol.2021.117112
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发表时间：
2021-04
影响因子：
8.9
通讯作者：
Jing Yu;Wei Zhang;Yang Tan;Zheng Zong;Q. Hao;C. Tian;Hua Zhang;Jun Li;Yunting Fang;Gan Zhang
中科院分区：
文献类型：
--
作者：
Jing Yu;Wei Zhang;Yang Tan;Zheng Zong;Q. Hao;C. Tian;Hua Zhang;Jun Li;Yunting Fang;Gan Zhang
河流中过量的硝酸盐（NO3−）会导致水质恶化，也会直接输入河口和海洋，从而对其生态系统的稳定性构成严重威胁。对渤海30条入海河流中NO3-的浓度、同位素组成及来源进行了全面调查。NO3--N的平均浓度为2.24 ± 2.11 mg L-1，具有明显的季节和空间变化。结果表明，渤海年NO3--N排放量为104.24 kt，其中黄河流域和辽河流域的贡献最大。δ 15 N-NO3 −的范围为-1.1 ‰至+33.2‰（平均值为+11.4 ± 5.0‰），没有明显的季节和空间差异; δ 18 O-NO3 −的平均值为+9.4 ± 7.2‰，6月份的值要高得多。根据MixSIAR模型，粪便（24.3 ± 7.5%）和污水（19.1 ± 14.5%）是30条河流中NO3−的主要来源，其次是NO3−肥料（16.3 ± 12.5%），土壤氮（15.5 ± 11.9%），大气沉积的NO3−（13.5 ± 5.7%）和NH 4+肥料（11.4 ± 8.9%）。这一发现强调了污水和粪便管理在河流NO3−中的重要作用。利用数学方法，模拟了各种来源对每条河流的贡献。结果表明，黄河、大辽河、辽河、小清河等河流的NO3-污染控制比其他河流更为迫切。我们相信，这一发现将为这30条河流和渤海NO3−污染的科学管理提供指导。
Excessive nitrate (NO3−) in rivers can lead to water quality deterioration, and can also be directly input into estuaries and oceans, thus posing a serious threat to the stability of their ecosystems. In this study, the concentration, isotopes and sources of NO3−in 30 rivers discharging into the Bohai Sea were comprehensively investigated. The mean concentration of NO3−-N was 2.24 ± 2.11 mg L−1, with obvious seasonal and spatial variations. In total, 104.24 kt of NO3−-N was discharged into the Bohai Sea annually, to which the Yellow River Basin and Liao River Basin made the largest contributions. The range of δ15N–NO3−was −1.1‰ to +33.2‰ (mean value, +11.4 ± 5.0‰), with no significant seasonal or spatial differences; the mean value of δ18O–NO3−was +9.4 ± 7.2‰, with much higher values seen in June. Based on the MixSIAR model, manure (24.3 ± 7.5%) and sewage (19.1 ± 14.5%) were the primary sources of NO3−in the 30 rivers, followed by NO3−fertilizers (16.3 ± 12.5%), soil N (15.5 ± 11.9%), atmospheric deposition of NO3−(13.5 ± 5.7%) and NH4+fertilizers (11.4 ± 8.9%). This finding highlights the vital roles of sewage and manure management in riverine NO3−. Using a mathematical method, the contributions of various sources to each river were simulated. The results indicated that management of the Yellow River, Daliao River, Liao River, and Xiaoqing River is more urgently needed than that of other rivers to control Bohai NO3−pollution. We believe that this finding will provide guidance for scientific management of NO3−pollution in these 30 rivers and the Bohai Sea.