摘要
地下水作为一种主要的饮用水和重要农业用水水源, 其环境质量状况关乎人类健康、粮食安全与生态可持续发展。本研究对太子河流域地表水、地下水的O3--N污染状况进行了调查, 并结合水化学与NO3^- -N同位素对其来源进行了分析, 探讨太子河流域地下水的水化学特征和硝酸盐污染状况, 为理解该区域地下水的水化学组成特点和开展水环境质量评价提供理论依据。结果表明, 太子河流域地表水氮主要以NO3^--N的形式存在, 占总氮78.38%, 浓度为0.75-6.40 mg·L^-1, 从上游到下游其含量变化趋势为先上升后下降, 在S6采样点达到最高值6.40 mg·L^-1; 地表水中NO2--N所占比例仅为0.78%, 且沿河流变化较小; 由于施用化肥肥料和有机氮的矿化作用, 下游地表水C1-浓度和NH4＋含量增高。太子河流域地下水NO3^-N浓度普遍高于地表水, NO3^--N浓度为0.57-55.78 mg·L^-1, 平均20.26 mg·L^-1; NO3^--N浓度为0-0.04 mg·L^-1，平均0.017 mg·L^-1。太子河流域地下水的NO2-和NO2-污染状况较重。NO3^--N同位素结果显示, 地表水的δ^15N为-0.74‰-13.27‰; 上游NO3^--N主要来源于土壤有机氮矿化, 中下游受农业化肥和人畜粪便共同影响。地下水δ^15N为5.7‰-17.5‰, 受人类活动影响较大, 人畜粪便堆肥和农业化肥的渗漏是主要影响因素。
As one of the main sources of drinking water and important irrigation water for agriculture, groundwater quality influences not only human health but also food security and ecological sustainability. This study attempted to lay the scientific basis for understanding nitrate pollution and groundwater quality evaluation. The study analyzed the composition of ions and concentration of nitrate in surface water and groundwater systems in Taizihe River Basin in the Northeast China. To assess nitrate pollution and identify the potential sources, surface water and groundwater samples were collected in Taizihe River Basin and the ions composition characteristics and nitrate isotopes in the groundwater samples analyzed. The results showed that nitrate was the dominant form of nitrogen pollution, accounting for 78.38% of total nitrogen concentration, with concentration range of 0.75-6.40 mg·L^-1 in surface water systems in Taizihe River Basin. The NO2--N was 0.78% of total nitrogen, with concentration range of 0-0.93 mg·L^-1 in surface water respectively. The concentration of NO3^--N increased from upstream to midstream regions in the basin and the highest value （6.40 mg·L^-1） occurred at site S6, from where it declined gradually along the course of the river. However, NO2--N showed less change along the river. Because of extensive use of chemical fertilizers and intensive mineralization of organic nitrogen, the concentration of Cl- and NH4＋ increased in the downstream regions. The concentration of NO3^- in groundwater was generally higher than that in surface water systems. The average concentration of NO3^- in groundwater was 20.26 mg·L^-1, suggesting that a severe NO3^- pollution existed in the groundwater systems in Taizi River Basin. A wide range of studies has used isotropy to trace nitrate pollution sources in aquatic environment. Analysis of environmental isotopes in the study area showed that δ^15N was in the range of -0.74‰-13.27‰ in surface water systems in Taizihe River Basin. Based on the results of nitrate isotope analysis, it was reasonable to conclude that NO3^- in surface water systems in the upstream regions was mainly from mineralization of soil organic nitrogen. Agricultural fertilizers and livestock manure were the main pollution sources of NO3^- in surface water systems in the middle and downstream regions of the basin. Higher δ^15N values （5.7‰-17.5‰） were noted in groundwater system in the basin, indicating that NO3^- in groundwater of Taizihe River Basin was mainly driven by human/animal feces and leakage of agricultural fertilizers.
出处
《中国生态农业学报》
CAS
CSCD
北大核心
2014年第8期980-986,共7页
Chinese Journal of Eco-Agriculture
基金
国家自然科学基金项目(41203081)
中央级公益性科研院所基本科研业务专项(GYK1291101)
国家水体污染控制与治理科技重大专项(2012ZX07501-001-02)资助
关键词
太子河流域
地表水
地下水
硝酸盐污染
离子组成
δ^15N
污染源
Taizihe River Basin
Surface water
Groundwater
Nitrate pollution
Ion composition
δ^15N isotope
Pollution source
