岩溶地下河硝酸盐转化与来源对比研究  

Comparative Study of Nitrate Transformation and Sources in Karst Underground Rivers

作　　者：文浩龙 杨平恒[1,2] 华茂松 贾亚男[1] 杨丰田 WEN Haolong;YANG Pingheng;HUA Maosong;JIA Yanan;YANG Fengtian(School of Geographic Sciences,Southwest University/Ministry of Natural Resources,Karst Ecological Environment Chongqing Nanchuan Field Base,Chongqing 400715;Key Laboratory of Karst Ecosystem and Rock Desertification Control,Ministry of Natural Resources/Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin Guangxi 541004;College of New Energy and Environment,Jilin University/Key Laboratory of Groundwater Resources and Environment,Ministry of Education,Changchun 130021)

机构地区：[1]西南大学地理科学学院/自然资源部岩溶生态环境-重庆南川野外基地,重庆400715 [2]自然资源部岩溶生态系统与石漠化治理重点实验室/中国地质科学院岩溶地质研究所,广西桂林541004 [3]吉林大学新能源与环境学院/教育部地下水资源与环境重点实验室,长春130021

出　　处：《西南大学学报（自然科学版）》2023年第5期172-184,共13页Journal of Southwest University(Natural Science Edition)

基　　金：自然资源部岩溶生态系统与石漠化治理重点实验室开放基金专项(KDL202102);重庆市教育委员会创新人才培养项目(CY220211).

摘　　要：为明确不同自然条件和人类活动影响下岩溶地下河硝酸盐污染源的时空分布及硝酸盐转化特征,以两个自然条件相似但人类活动方式不同的岩溶区--重庆市金佛山水房泉岩溶地下河流域和青木关岩溶地下河流域为例,系统测定了主要水化学指标及硝酸盐氮氧同位素(δ^(15) N_(-nitrate)和δ^(18) O_(-nitrate))组成,分析了硝酸盐的转化过程,使用MixSIAR模型,对不同污染源的时空分布比例及贡献概率进行解析.结果表明:①在研究期间,水房泉与青木关地下河流域水化学特征相似,均为HCO^(-)_(3)-Ca^(2+)型.②两个地下河流域均以硝化作用为主要过程,但也发生反硝化作用,如水房泉流域药池坝污水、化粪池和青木关流域果园污水.③MixSIAR模型运算表明,水房泉地下河流域土壤有机氮来源占比高达60.8%,粪肥污水来源为31.3%,大气降水占比较低,为7.9%;青木关地下河流域化肥来源占比高达41.9%,土壤有机氮和粪肥污水占比相近,分别为29.4%和24.9%,大气降水占比仅为3.8%.④水房泉地下河流域大气降水、土壤有机氮和粪肥污水的不确定指数分别为0.064,0.384和0.427,而青木关地下河流域大气降水、粪肥污水、化肥和土壤有机氮的不确定指数分别为0.175,0.698,0.847和0.864.青木关地下河流域范围更广,人类活动更复杂,地下河的粪肥污水、化肥和土壤有机氮多以较大范围的非点源污染排放,导致各硝酸盐来源贡献率不确定性远高于水房泉地下河流域.In order to clarify the transformation and source of nitrate in karst underground rivers under the influence of different natural conditions and human activities,taking two karst areas with similar natural conditions but different ways of human activities-the Fangquan karst underground river basin in Jinfoshan,Chongqing and the Qingmuguan karst underground river basin as examples,the main hydrochemical indexes and dual nitrate isotopes(δ^(15) N_(-nitrate) andδ^(18) O_(-nitrate))of the Shuifangspring and Qingmuguan underground river basins in Chongqing were systematically employed to clarify the temporal and spatial distribution of nitrate pollution sources and the characteristics of nitrate transformation in karst underground rivers under the influence of different natural conditions and human activities.The nitrate transformation process,distribution proportion,and contribution probability of different nitrate sources were analyzed by the dual nitrate isotopes and Bayesian MixSIAR model.Results show that:During the study period,the chemical characteristics of Shuifangspring and Qingmuguan underground river basins were similar,both were HCO^(-)_(3)-Ca^(2+)type.Nitrification was the main process in both underground river basins,but denitrification also occurred,such as sewage of Yaochiba,Huafengchi in Shuifangspring watershed and sewage of Guoyuan in Qingmuguan watershed.δ^(15) N_(-nitrate),δ^(18) O_(-nitrate) values and MixSIAR model calculation showed that the proportion of soil organic nitrogen,manure and sewage,and atmospheric precipitation in Shuifangspring underground river basin were 60.8%,31.3%,and 7.9%,respectively.The proportion of chemical fertilizer,soil organic nitrogen,manure and sewage,and atmospheric precipitation in Qingmuguan underground river basin were 41.9%,29.4%,24.9%,3.8%,respectively.The uncertainty indexes of atmospheric precipitation,soil organic nitrogen,and manure sewage in Shuifangspring underground river basin were 0.064,0.384,0.427 respectively,while the uncertainty indexes of at

关 键 词：硝酸盐氮氧同位素 MixSIAR模型 岩溶地下河 来源解析 重庆 

分 类 号：P641.3[天文地球—地质矿产勘探]