| 湖北泉水河流域水化学特征和硝酸盐来源示踪 |
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| 引用本文： | 李严,曹明达,靳孟贵,张结,黄鑫.湖北泉水河流域水化学特征和硝酸盐来源示踪[J].地球科学,2020,45(3):1061-1070. |
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| 作者姓名： | 李严 曹明达 靳孟贵 张结 黄鑫 |
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| 作者单位： | 1.中国地质大学盆地水文过程与湿地生态恢复学术创新基地, 湖北武汉 430074 |
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| 基金项目： | 国家自然科学基金面上项目Nos.41672246国家自然科学基金面上项目41877192 |
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| 摘 要： | 目前针对喀斯特山区及平原过渡带天然河流硝酸盐的来源识别与追踪的研究鲜有报道，也较少考虑湿润气候区反季节性干旱气候特征对硝酸盐迁移规律的影响.以汉江二级支流泉水河流域为例，分析了从源头喀斯特地区、中间过渡区、平原区地表水和地下水硝酸盐含量及组成的空间变化，采用氮氧同位素识别地表水和地下水硝酸盐来源，利用SIAR模型定量计算各污染源的贡献率.结果表明:土壤有机氮、污水粪便、化肥和大气沉降对地下水硝酸盐来源贡献占比分别为31.4%、20.0%、29.6%和19.0%，对地表水硝酸盐来源的比例分别为32.0%、30.0%、25.0%和13.0%，污水粪便对地表水硝酸盐贡献比例较地下水增高；坝上水样因水体较大，自净能力较强，受污水粪便的影响很小（仅为9.0%），坝上水样硝酸盐土壤有机氮、大气沉降和化肥的贡献占比分别为43.0%、11.0%和37.0%.枯水期河水主要由地下水缓慢补给，无地表径流汇入，土壤有机氮为河流主要的硝酸盐来源，河流中下游更易受人类活动影响，生活污水和化肥对河流硝酸盐贡献增大.
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| 关 键 词： | 硝酸盐污染 氮、氧同位素 来源识别 SIAR模型 泉水河 水文地质 |
| 收稿时间： | 2019-02-13 |
Hydrochemical Characteristics and Tracing of Nitrate Sources in Quanshui River Catchment,Hubei Province |
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| Abstract: | There are few studies on the source identification of nitrate in the natural rivers in karst area, and even fewer on the influence of the anti-seasonal arid climate on the nitrate transportation. In this paper, δ15N and δ18O isotopic tracing method is used to analyze the source of nitrate in surface water and groundwater of Quanshui River, a branch of Hangjiang River and to determine the biological and chemical transformation process of nitrate. The contribution rate of each pollution terminal element was determined quantitatively by using the model of Stable Isotope Analysis in R (SIAR). The results show that soil organic nitrogen, sewage manure, fertilizer and atmospheric subsidence contributed 31.4%, 20.0%, 29.6% and 19.0% respectively to the nitrate source of groundwater, and the proportion of nitrate source to surface water was 32.0%, 30.0%, 25.0% and 13.0%. The contribution of sewage manure to surface water nitrate is significantly higher than that of groundwater. Due to the large water body, the water in the reservoir has strong self-purification ability and is almost unaffected by sewage manure (only 9.0%).The contribution of soil organic nitrogen, atmospheric subsidence and fertilizer in the nitrate soil of the reservoir was 43.0%, 11.0% and 37.0%, respectively. In dry season, groundwater is mainly recharged slowly by groundwater. Because groundwater is affected by soil in vadose zone, soil organic nitrogen is the main source of nitrate in the river. The downstream of the river is more susceptible to human activities, and the contribution of domestic sewage and chemical fertilizer to nitrate in rivers increases. |
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