| 木沥河流域氮素污染及其污染源解析 |
| 摘要点击 1752 全文点击 800 投稿时间：2019-12-09 修订日期：2020-02-06 |
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| 中文关键词 木沥河流域 氮素污染 氮同位素 氧同位素 多元线性混合模型 |
| 英文关键词 Muli River basin nitrogen pollution nitrogen isotope oxygen isotope multiple linear mixture model |
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| 中文摘要 |
| 为甄别粤港澳大湾区木沥河流域氮污染物来源，本研究应用铵盐同位素示踪技术、硝酸盐同位素示踪技术和多元线性混合模型等方法有效识别了该流域氮素来源的变化.结果表明，木沥河流域氮素污染严重，木沥河水体NH4+-N和NO3--N浓度显著高于上游两条支流；除此之外，大坑山支流断面和木沥河下游养殖区断面虽无明显人口居住，仍然面临较高的氮素污染风险.铵盐同位素和硝酸盐同位素定性分析结果表明，木沥河流域氮素污染主要来源于土壤、肥料、大气颗粒物和动物及人排泄物；多元线性混合模型计算结果显示，大坑山支流上流处氮素主要来源为大气沉降，其贡献率在80%左右；鸡笼坑支流上游土壤有机氮平均贡献率可达33%，大于大坑山支流（9%）和木沥河（24%）；大坑山支流下游、鸡笼坑支流下游和木沥河中上游污水及粪肥对氮素污染贡献率最高可达70%；值得注意的是，养殖区断面远离人口聚集地，各种养殖已被清理，但污水及粪肥的贡献率仍高达56%，远高于木沥河下游的淡水河水闸断面（3%），这可能要归咎于沉积物中残留的禽畜排泄物.本研究定性和定量地分析了木沥河流域氮素来源，为大湾区的水质管理和污染源治理提供了理论依据. |
| 英文摘要 |
| To identify the sources of nitrogen pollutants in the Muli River basin in the Guangdong-Hong Kong-Macao Greater Bay Area, ammonium salt isotope tracer technology, nitrate isotope tracer technology, and a multiple linear mixing model were applied in this study to effectively identify the changes of nitrogen sources in the basin. The results showed that nitrogen pollution in the Muli River basin was serious, and the concentrations of NH4+-N and NO3--N in the confluence were higher than in the two tributaries. In addition, although there was no obvious population residence at the upstream or downstream of the Muli River basin, higher nitrogen pollution still occurred at some sites (Dakengshan tributary and aquiculture area). Qualitative analysis of ammonium salt and nitrate isotopes showed that nitrogen pollution in the Muli River basin mainly came from soil, fertilizer, atmospheric particles, and animal and human excreta. The results of the multiple linear mixing model showed that the main source of nitrogen in the upper reaches of the Dakengshan tributary is atmospheric subsidence, with a contribution rate of about 80%. The average contribution rate of soil organic nitrogen in the upper reaches of the Jilongkeng tributary was 33%, higher than those of the Dakengshan tributary (9%) and Muli River (24%). The contribution rate of sewage and manure to nitrogen pollution was up to 70% in the lower reaches of the Dakengshan tributary, the lower reaches of the Jilongkeng tributary, and the middle and upper reaches of the Muli River. In addition, while all forms of livestock and poultry farming and aquiculture activity were stopped, the contribution rate of sewage and manure in Yangzhiqu was found to be still as high as 56%, which is much higher than that at the Danshui River Dam section in the lower part of the Muli River (3%); this may be due to residual livestock waste in the sediment. This study qualitatively and quantitatively analyzed the nitrogen sources of the Muli River basin, which provids a theoretical basis for pollution source management in the Greater Bay Area. |
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