| 氮和氧同位素示踪伊洛河河水硝酸盐来源及转化过程 |
| 摘要点击 1403 全文点击 484 投稿时间：2022-07-07 修订日期：2022-09-05 |
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| 中文关键词 硝酸盐来源 氮和氧同位素 贝叶斯同位素混合模型 伊洛河流域 黄河流域生态文明 |
| 英文关键词 nitrate sources nitrogen and oxygen isotopes Bayesian isotope mixing model Yiluo River Basin ecological civilization in the Yellow River Basin |
| 作者 | 单位 | E-mail | | 郭文静 | 河南理工大学资源环境学院, 焦作 454003 | 18339185878@163.com | | 张东 | 河南理工大学资源环境学院, 焦作 454003 | zhangdong@hpu.edu.cn | | 蒋浩 | 中国科学院武汉植物园, 水生植物与流域生态重点实验室, 武汉 430074 | | | 吴洋洋 | 河南理工大学资源环境学院, 焦作 454003 | | | 张郭妙 | 河南理工大学资源环境学院, 焦作 454003 | | | 段慧真 | 河南理工大学资源环境学院, 焦作 454003 | | | 许梦军 | 河南理工大学资源环境学院, 焦作 454003 | | | 麻冰涓 | 河南理工大学资源环境学院, 焦作 454003 | | | 陈昊 | 河南理工大学资源环境学院, 焦作 454003 | | | 黄兴宇 | 河南理工大学资源环境学院, 焦作 454003 | |
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| 中文摘要 |
| 河流硝酸盐(NO-3)浓度及氮和氧同位素组成(δ15 N-NO-3和δ18 O-NO-3)可以辨识河水NO-3受自然过程和人为输入的影响,但流域不同土地利用方式对河水NO-3来源及转化过程的影响尚不明确,特别是山区人为输入对河水NO-3的影响仍不清楚.选择土地利用空间异质性显著的伊河和洛河作为研究对象,借助水体水化学组成,氢氧同位素(δD-H2 O和δ18 O-H2 O)、δ15 N-NO-3和δ18 O-NO-3,辨识不同土地利用方式影响下河水NO-3来源及转化途径.结果表明:①伊河与洛河河水ρ(NO-3)均值分别6.57和9.29 mg·L-1,δ15 N-NO-3均值分别为9.6‰和10.4‰,δ18 O-NO-3均值分别为-2.2‰和-2.7‰;结合δ15 N-NO-3和δ18 O-NO-3分析,伊河和洛河水中NO-3主要受多来源混合控制,同时洛河存在脱氮作用,但伊河生物去除作用较弱.②综合考虑干流和支流河水δ15 N-NO-3和δ18 O-NO-3空间分布,结合贝叶斯同位素混合模型,计算洛河和伊河河水硝酸盐来源,发现洛河上游和伊河上游森林植被广泛,但生活污水和粪肥影响较大;上游土壤有机氮和化学肥料贡献比例大于下游;下游生活污水和粪肥贡献继续增加.研究结果证实点源污染(城镇生活污水和粪肥)对伊洛河流域河水NO-3来源的影响,同时面源污染(化肥)贡献并未随着下游农业活动增加而升高.因此需要重视伊洛河流域内点源污染的有效治理,保障黄河流域生态文明高质量发展. |
| 英文摘要 |
| The impacts of natural processes and anthropogenic input on riverine nitrate (NO-3) could be identified by NO-3 concentrations and nitrogen and oxygen isotope ratios (δ15N-NO-3 and δ18O-NO-3); however, the effects of variable land use on riverine NO-3 sources and transformations remain unclear. In particular, the human impacts on riverine NO-3 in mountain areas are still unknown. The Yihe River and Luohe River were used to elucidate this question due to their spatially heterogeneous land use. Hydrochemical compositions, water isotope ratios (δD-H2O and δ18O-H2O), and δ15N-NO-3 and δ18O-NO-3 values were utilized to constrain the NO-3 sources and transformations affected by different land use types. The results indicated that ① the mean nitrate concentrations in the Yihe River and Luohe River waters were 6.57 and 9.29 mg·L-1, the mean values of δ15N-NO-3 were 9.6‰ and 10.4‰, and the average δ18O-NO-3 values were -2.2‰ and -2.7‰, respectively. Based on the analysis of δ15N-NO-3 and δ18O-NO-3 values, the NO-3 in the Yihe and Luohe Rivers were derived from multiple sources, and nitrogen removal existed in the Luohe River, but the biological removal in the Yihe River was weak. ② The contributions of different nitrate sources were calculated using a Bayesian isotope mixing model (BIMM) based on δ15N-NO-3 and δ18O-NO-3 values of river water in the mainstream and tributaries with spatial locations. The results revealed that sewage and manure had major impacts on riverine nitrate in the upper reaches of both the Luohe River and Yihe River, where forest vegetation was widely distributed. However, the contributions from soil organic nitrogen and chemical fertilizer were higher in the upper reaches than in downstream ones. The contributions of sewage and manure still increased in the downstream reaches. Our results confirmed the primary impacts of point sources, e.g., sewage and manure, on riverine nitrate in the studied area, and the contributions of nonpoint sources, e.g., chemical fertilizer, had not increased as the agricultural activities elevated the downstream. Therefore, more attention should be paid to point source pollution treatment, and the high-quality development of ecological civilization in the Yellow River Basin should be maintained. |
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