摘要
地表水硝酸盐污染已经受到世界研究者的广泛关注,中国地表水系统硝酸盐污染情况也不容乐观.为了解中国地表水硝酸盐分布、来源和转化机制,本研究系统收集了全国7大地区的71条主要河流硝酸盐数据,分析了地表水硝酸盐的分布及污染情况,并且通过硝酸盐氮氧同位素特征值揭示了不同地区、不同流域水体硝酸盐的主要来源.结果表明,我国7.83%河流硝酸盐质量浓度超过了标准限值(45 mg·L^-1).牡丹江、海河和长江入海口的硝酸盐质量浓度超过90 mg·L^-1,呈现重度污染现象.中国地表水δ15N-NO3和δ18O-NO3特征值范围分别为-23.5‰~26.99‰和-12.7‰~83.5‰.研究表明:东北、华中、华东地区地表水硝酸盐主要来源为生活污水,西北和华北地区地表水硝酸盐主要来源为生活污水、无机化肥和土壤有机质硝化,西南和华南地区地表水硝酸盐主要来源为无机化肥和生活污水.通过相关性分析得到中国地表水硝酸盐质量浓度与常住人口、废水排放量、农用氮肥施用折纯量和人均GDP呈正相关关系.解决污染问题和防止中国地表水进一步污染迫在眉睫,中国政府出台的新的水十条解决了之前的不足,但是控制和修复地表水污染还需要几十年的努力.西北、华北、西南和华南地区不仅要增加城市、县区污水处理厂运行规模,政府还要控制和管理农业化肥的使用量.东北、华中和华东地区需要进一步控制点源污染,减少工业废水和生活污水排放到河流.
The nitrate pollution of surface water has attracted worldwide attention,and it is not optimistic in China.To identify the distribution,sources,and transformation mechanisms of nitrate in China’s surface waters,the nitrate data of 71 major rivers from 7 regions were systematically collected.The spatial distribution of nitrate concentrations in surface water was analyzed,and the main nitrate pollution sources were revealed based on nitrogen and oxygen isotopes of nitrate.The results show that approximately 7.83%of rivers in China exceeded the Chinese drinking water standard for nitrate(45 mg·L^-1).The concentrations of nitrate in Mudanjiang,Haihe River,and the estuary of Yangtze River was even more than 90 mg·L^-1,which indicates a serious pollution phenomenon.The isotopic compositions of surface water in China ranged from-23.5‰to 26.99‰forδ15N-NO3 and from-12.7‰to 83.5‰forδ18O-NO3.The main sources of nitrate are domestic sewage in Northeast,Central,and East China,while those are inorganic fertilizers and domestic sewage in Southwest and South China.The nitrate sources of surface water in Northwest and North China are complex,mainly from domestic sewage,inorganic fertilizer,and nitration of soil organic matter.Through correlation analysis,it is found that the nitrate concentrations of surface water have a positive relationship with population,wastewater discharge,agricultural nitrogen fertilizer application,and GDP per capita in China.It is urgent to solve the problem of pollution and prevent the further pollution of China’s surface waters.The new"10-Point Water Plan"issued by the Chinese government solved the previous problems,but it will take decades to control and repair the polluted surface waters.In Northwest,North China,Southwest,and South China,not only the scale of sewage treatment plants in cities and counties should be increased but also the use of agricultural fertilizers should be controlled and managed by the government.Northeast,Central,and East China need to further control point source pollution and reduce the discharge of industrial wastewater and domestic sewage into rivers.
作者
张鑫
张妍
毕直磊
山泽萱
任丽江
李琦
ZHANG Xin;ZHANG Yan;BI Zhi-lei;SHAN Ze-xuan;REN Li-jiang;LI Qi(Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity,College of Urban and Environmental Sciences,Northwest University,Xi'an 710127,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2020年第4期1594-1606,共13页
Environmental Science
基金
国家自然科学基金项目(41601017)
陕西省高校科协青年人才托举计划项目(20190702)。
关键词
硝酸盐
地表水
分布
来源
氮氧同位素
nitrate
surface water
distribution
source
nitrogen and oxygen isotopes
