摘要
以漓江流域境内地表河和地下河为研究对象,通过测定、分析水体中的水化学组成以及δ13CDIC、δ15N-NO3-、δ18O-NO3-等,利用同位素质量平衡混合模型,初步探讨了漓江流域境内DIC、硝酸盐的分布特征及其来源.结果表明:漓江流域DIC(即HCO3-)浓度和无机碳稳定同位素(δ13CDIC)分别在12.20~402.60 mg·L-1和-17.29‰^-10.01‰,平均值分别为140.3 mg·L-1和-13.06‰.NO3-浓度在2.37~35.38 mg·L-1,δ15N-NO3-在0.99‰~11.09‰,均展现出明显的空间变异特征.有机肥和污水对漓江流域硝酸盐的贡献最为显著,贡献比达57.00%.其次是化肥、降雨中的NH4+和土壤N,贡献比分别是36.45%,6.55%.流域内DIC主要来源于碳酸盐岩的风化和土壤CO2的溶解,同时也受硝酸溶蚀碳酸盐岩和大气CO2的影响.结果可为定制有效的控制硝酸盐的输入途径,净化水质测略提供依据.
The distribution characteristics and sources of DIC and nitrate in the Lijiang River basin are studied using isotope mass balance models,by which the hydrochemical composition of the surface and underground rivers in the Lijiang River basin,δ13CDIC,δ15N-NO3-andδ18O-NO3-are measured and analyzed.The results show that the concentration of DIC(HCO3-)and inorganic carbon stable isotopes(δ13CDIC)in Lijiang River basin range from 12.20 to 402.60 mg·L-1,and from-17.29‰to-10.01‰respectively,with the average value of 140.3 mg·L-1and-13.06‰respectively.The concentration of NO3-is between 2.37 and 35.38 mg·L-1,andδ15N-NO3-is between 0.99‰and 11.09‰,both showing obvious spatial variation characteristics.It is concluded that organic manure and sewage have the most significant contribution to nitrate in the Lijiang River basin,with a contribution ratio of 57.00%,which is followed by NH4+in fertilizer and precipitation,and soil N,with contribution ratios of 36.45%and 6.55%respectively.The source of DIC in the drainage basin is mainly due to the weathering of carbonate rocks and the dissolution of soil CO2,which is also affected by the corrosion of carbonate rocks by nitric acid and atmospheric CO2.The corrosion intensity of nitric acid on carbonate rocks is controlled not only by the degree of nitrogen pollution in water,but also by the source of nitrogen pollution.The results can provide a basis for customizing effective nitrate input channels and purifying water quality.
作者
任梦梦
黄芬
胡晓农
曹建华
张鹏
Ren Mengmeng;Huang Fen;X.Hu Bill;Cao Jianhua;Zhang Peng(School of Water Resources and Erwironment,China Universily of Geosciences,Beiing 100083,China;Key Laboratory of Karst Dynamics,Guangxi Instiute of Karst Geology,Chinese Academy of Geological Sciences,Ministry of Natural Resoures,Guilin 541004.China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2020年第5期1830-1843,共14页
Earth Science
基金
国家自然科学基金重点项目(No.41530316)
国家自然科学基金面上项目(No.41772385)
广西自然科学基金面上项目(No.2016GXNSFAA380034)
国家重点研发专项(No.2016YFC05025)。
作者简介
任梦梦(1994-),男,硕士研究生,主要研究方向为岩溶水文地质。0R0DI:0000-000-6677-9828.E-mail:1378721875@qq.com;通讯作者:黄芬,E-mail:hfen@karst.ac.cn。
