典型岩溶地下河系统不同水体中硝酸盐时空分布规律及其影响因素分析
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摘要
岩溶地下河在西南地区分布极广,作为当地重要的生活和生产水源,近年来遭受了不同程度的污染,其中硝酸盐污染是岩溶地下河面临的最突出最普遍的问题之一。且由于岩溶地区含水层的高度非均质性,使得硝酸盐的分布及其形成规律很难通过模拟手段揭示。本文选取广西柳州市大良镇官村的典型岩溶地下河系统作为研究对象,分别于丰水期和枯水期系统采集不同水体样品。通过水化学及氢氧同位素示踪和统计分析等方法,分析硝酸盐浓度及稳定同位素的变化特征。结果表明,该岩溶地下河系统中,丰水期和枯水期硝酸盐浓度变化趋势一致,上湖洞到下湖洞段硝酸盐浓度逐渐升高,下湖洞到地下河出口硝酸盐浓度呈降低趋势;水体明显受到人为活动的影响,水体中的硝酸盐主要来自农业源和生活源,农业源的输入对水体中硝酸盐浓度的影响较强;由于不同季节地下河系统硝酸盐来源的差异及补给水的不同,使地下河系统不同水体的氢氧同位素特征和硝酸盐浓度分布呈现明显的季节性差异,丰水期水体中硝酸盐平均浓度大于枯水期硝酸盐平均浓度;受外源硝酸盐输入、不同补给水的混合作用及还原作用的影响,岩溶地下河系统中不同水体的硝酸盐浓度分布亦呈现明显的空间差异性。本研究通过示踪的方法分析了硝酸盐在岩溶地下河系统中的时空分布规律及其影响因素,对岩溶地区面源污染防治策略的形成具有重要意义。
Karst underground rivers, which are widely distributed in karst areas in Southwest China, are important water resources. In recent years, with the continuous economic development, karst underground rivers have been rendered polluted to variable proportions. Nitrate pollution is a prominent and common problem in karst underground rivers. The high heterogeneity of karst aquifers makes it difficult to decipher the formation and distribution process of nitrate by simulation. The typical karst underground river system in Guancun Village, Daliang Town, Liuzhou City, Guangxi was selected as the study area. The land use was dominated by agriculture and the primary pollutant was nitrate. Multiple water samples were collected during the wet and dry seasons. The nitrate concentration and stable isotope variation characteristics were analyzed employing tracing and statistical methods. The results indicated that in the Guancun karst underground river system the trending of nitrate concentration during the wet and dry periods were consistent. The nitrate levels gradually increased from the Shanghu Cave to Xiahu Cave. On the contrary, the nitrate levels decreased from the Xiahu Cave to the underground river outlet. The waters of study area were obviously affected by human activities. The nitrates in the water primarily originated from agricultural and living sources. The input from the agricultural source had a profound influence on the nitrate concentration in the water. Due to the different sources of nitrate in the recharge water in different seasons, the distribution of nitrate concentration and stable water isotopes showed significant seasonal characteristics of the underground river system with the average nitrate concentration during wet season being greater than that during the dry season. As a result of the input of exogenous nitrate, mixing waters, and reduction processes, the distribution of nitrate concentration in karst underground river system also exhibit obvious spatial distribution characteristics. In this study, tracing method was employed to analyze the spatial and temporal distribution characteristics and the factors influencing nitrate levels in the karst underground river system. The conclusions arrived at would be significant in formulating non-point source pollution prevention strategies in karst areas.
Karst underground rivers, which are widely distributed in karst areas in Southwest China, are important water resources. In recent years, with the continuous economic development, karst underground rivers have been rendered polluted to variable proportions. Nitrate pollution is a prominent and common problem in karst underground rivers. The high heterogeneity of karst aquifers makes it difficult to decipher the formation and distribution process of nitrate by simulation. The typical karst underground river system in Guancun Village, Daliang Town, Liuzhou City, Guangxi was selected as the study area. The land use was dominated by agriculture and the primary pollutant was nitrate. Multiple water samples were collected during the wet and dry seasons. The nitrate concentration and stable isotope variation characteristics were analyzed employing tracing and statistical methods. The results indicated that in the Guancun karst underground river system the trending of nitrate concentration during the wet and dry periods were consistent. The nitrate levels gradually increased from the Shanghu Cave to Xiahu Cave. On the contrary, the nitrate levels decreased from the Xiahu Cave to the underground river outlet. The waters of study area were obviously affected by human activities. The nitrates in the water primarily originated from agricultural and living sources. The input from the agricultural source had a profound influence on the nitrate concentration in the water. Due to the different sources of nitrate in the recharge water in different seasons, the distribution of nitrate concentration and stable water isotopes showed significant seasonal characteristics of the underground river system with the average nitrate concentration during wet season being greater than that during the dry season. As a result of the input of exogenous nitrate, mixing waters, and reduction processes, the distribution of nitrate concentration in karst underground river system also exhibit obvious spatial distribution characteristics. In this study, tracing method was employed to analyze the spatial and temporal distribution characteristics and the factors influencing nitrate levels in the karst underground river system. The conclusions arrived at would be significant in formulating non-point source pollution prevention strategies in karst areas.
引文
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[7]李思亮,刘丛强.贵阳地下水硝酸盐氧同位素特征及应用[J].中国岩溶,2006,25(2):108-111LI S L,LIU C Q.The character and application ofδ18O-NO3-in the groundwater of Guiyang[J].Carsologica Sinica,2006,25(2):108-111
[8]王开然.桂林东区峰林平原岩溶水系统氮的运移机理研究[D].重庆:西南大学,2013WANG K R.Migration mechanism of nitrogen in peak forest plain karst water system in eastern Guilin[D].Chongqing:Southwest University,2013
[9]郭芳.官村地下河流域氮流失及其影响因素研究[D].重庆:西南大学,2008GUO F.Characteristic and influencing factors of nitrogen loss in Guancun karst subterranean river catchment[D].Chongqing:Southwest University,2008
[10]张陶,蒲俊兵,袁道先,等.亚热带典型岩溶区地表溪流水文地球化学昼夜变化及其影响因素研究[J].环境科学,2014,35(8):2944-2951ZHANG T,PU J B,YUAN D X,et al.Diel variations of hydrochemistry and influencing factors in a surface stream in subtropical karst area,SW China[J].Environmental Science,2014,35(8):2944-2951
[11]章程,汪进良,蒲俊兵.地下河出口河流水化学昼夜动态变化--生物地球化学过程的控制[J].地球学报,2015,36(2):197-203ZHANG C,WANG J L,PU J B.Diel aqueous chemical cycling in a typical karst spring-fed stream:Controls of biogeochemical processes[J].Acta Geoscientia Sinica,2015,36(2):197-203
[12]张陶,蒲俊兵,袁道先,等.广西官村岩溶溪流中生物地球化学控制的DIC和NO3-昼夜变化研究[J].地质学报,2016,90(8):1965-1976ZHANG T,PU J B,YUAN D X,et al.Biogeochemical controls on daily cycling of DIC and NO3-of Guancun karst stream in Guangxi[J].Acta Geologica Sinica,2016,90(8):1965-1976
[13]李丽,蒲俊兵,李建鸿,等.岩溶地下河补给的地表溪流溶解无机碳及其稳定同位素组成的时空变化[J].环境科学,2017,38(2):527-534LI L,PU J B,LI J H,et al.Temporal and spatial variations of dissolved inorganic carbon and its stable isotopic composition in the surface stream of karst groundwater recharge[J].Environmental Science,2017,38(2):527-534
[14]钟铿,熊天赐,杨锦兰,等.广西壮族自治区柳州市地质系列图集[R].南宁:广西壮族自治区地质矿产局,1988ZHONG K,XIONG T C,YANG J L,et al.Geological Series Atlas of Liuzhou City,Guangxi Zhuang Autonomous Region[R].Nanning:Geological and Mineral Bureau of Guangxi Zhuang Autonomous Region,1988
[15]董海彪,卢文喜,安永凯,等.基于对应分析法的鄂尔多斯盆地东北部地下水污染分析[J].中国环境科学,2015,35(11):3371-3378DONG H B,LU W X,AN Y K,et al.Groundwater pollution assessment in northeastern Ordos basin based on correspondence analysis method[J].China Environmental Science,2015,35(11):3371-3378
[16]WEI Y N,FAN W,WANG W,et al.Identification of nitrate pollution sources of groundwater and analysis of potential pollution paths in loess regions:A case study in Tongchuan Region,China[J].Environmental Earth Sciences,2017,76(12):423
[17]LIU C Q,LI S L,LANG Y C,et al.Usingδ15N-andδ18O-values to identify nitrate sources in karst ground water,Guiyang,southwest China[J].Environmental Science&Technology,2006,40(22):6928-6933
[18]CAO Y J,TANG C Y,SONG X F,et al.Characteristics of nitrate in major rivers and aquifers of the Sanjiang Plain,China[J].Journal of Environmental Monitoring,2012,14(10):2624-2633
[19]梁慧雅,翟德勤,孔晓乐,等.府河-白洋淀硝酸盐来源判定及迁移转化规律[J].中国生态农业学报,2017,25(8):1236-1244LIANG H Y,ZHAI D Q,KONG X L,et al.Sources,migration and transformation of nitrate in Fuhe River and Baiyangdian Lake,China[J].Chinese Journal of Eco-Agriculture,2017,25(8):1236-1244
[20]吴起鑫,韩贵琳,李富山,等.珠江源区南、北盘江丰水期水化学组成特征及来源分析[J].环境化学,2015,34(7):1289-1296WU Q X,HAN G L,LI F S,et al.Characteristic and source analysis of major ions in Nanpanjiang and Beipanjiang at the upper Pearl River during the wet season[J].Environment Chemistry,2015,34(7):1289-1296
[21]LI S L,LIU C Q,LI J,et al.Assessment of the sources of nitrate in the Changjiang River,China using a nitrogen and oxygen isotopic approach[J].Environment Science&Technology,2010,44(5):1573-1578
[22]XING M,LIU W G,WANG Z F,et al.Relationship of nitrate isotopic character to population density in the Loess Plateau of Northwest China[J].Applied Geochemistry,2013,35:110-119
[23]方晶晶.河北平原邯郸地区地下水硝酸盐污染来源及迁移转化过程的多元素同位素及微生物(E.Coil)示踪[D].武汉:中国地质大学,2014FANG J J.Use of multi-isotope and microbial technology(E.coil)for evaluating source and transformation of nitrate in the groundwater in Handan Area in the North China Plain[D].Wuhan:China University of Geosciences,2014
[24]COOK P G,HERCZEG A L.Environmental Tracers in Subsurface Hydrology[M].Boston:Kluwer Academic Publishers,2000:80-90
[25]史婷婷,陈植华,张卫.湖北宜昌香溪河流域环境同位素特征及其水循环意义[J].地质科技情报,2012,31(6):161-167SHI T T,CHEN Z H,ZHANG W.Characteristics of environmental isotopes in Xiangxi River basin of Yichang,Hubei Province and its significance for hydrological cycle[J].Geological Science and Technology Information,2012,31(6):161-167
[26]张小娟,宋维峰,吴锦奎,等.元阳梯田水源区土壤水氢氧同位素特征[J].环境科学,2015,36(6):2102-2108ZHANG X J,SONG W F,WU J K,et al.Characteristics of hydrogen and oxygen isotopes of soil water in the water source area of Yuanyang terrace[J].Environmental Science,2015,36(6):2102-2108
[2]袁道先,薛禹群,傅家谟,等.防止我国西南岩溶地区地下河变成“下水道”的对策与建议[Z].中国科学院院士建议,2007,4:1-16YUAN D X,XUE Y Q,FU J M,et al.Countermeasures and suggestions to prevent underground rivers from becoming“sewers”in karst areas in Southwest China[Z].Chinese Academy of Sciences Academician Proposal,2007,4:1-16
[3]陈建耀,王亚,张洪波,等.地下水硝酸盐污染研究综述[J].地理科学进展,2006,25(1):34-44CHEN J Y,WANG Y,ZHANG H B,et al.Overview on the studies of nitrate pollution in groundwater[J].Progress in Geography,2006,25(1):34-44
[4]ZUO R,JIN S H,CHEN M H,et al.In-situ study of migration and transformation of nitrogen in groundwater based on continuous observations at a contaminated desert site[J].Journal of Contaminant Hydrology,2018,211:39-48
[5]PEROVI?M,OBRADOVI?V,KOVA?EVI?S,et al.Indicators of groundwater potential for nitrate transformation in a reductive environment[J].Water Environment Research,2017,89(1):4-16
[6]王仕琴,郑文波,孔晓乐.华北农区浅层地下水硝酸盐分布特征及其空间差异性[J].中国生态农业学报,2018,26(10):1476-1482WANG S Q,ZHENG W B,KONG X L.Spatial distribution characteristics of nitrate in shallow groundwater of the agricultural area of the North China Plain[J].Chinese Journal of Eco-Agriculture,2018,26(10):1476-1482
[7]李思亮,刘丛强.贵阳地下水硝酸盐氧同位素特征及应用[J].中国岩溶,2006,25(2):108-111LI S L,LIU C Q.The character and application ofδ18O-NO3-in the groundwater of Guiyang[J].Carsologica Sinica,2006,25(2):108-111
[8]王开然.桂林东区峰林平原岩溶水系统氮的运移机理研究[D].重庆:西南大学,2013WANG K R.Migration mechanism of nitrogen in peak forest plain karst water system in eastern Guilin[D].Chongqing:Southwest University,2013
[9]郭芳.官村地下河流域氮流失及其影响因素研究[D].重庆:西南大学,2008GUO F.Characteristic and influencing factors of nitrogen loss in Guancun karst subterranean river catchment[D].Chongqing:Southwest University,2008
[10]张陶,蒲俊兵,袁道先,等.亚热带典型岩溶区地表溪流水文地球化学昼夜变化及其影响因素研究[J].环境科学,2014,35(8):2944-2951ZHANG T,PU J B,YUAN D X,et al.Diel variations of hydrochemistry and influencing factors in a surface stream in subtropical karst area,SW China[J].Environmental Science,2014,35(8):2944-2951
[11]章程,汪进良,蒲俊兵.地下河出口河流水化学昼夜动态变化--生物地球化学过程的控制[J].地球学报,2015,36(2):197-203ZHANG C,WANG J L,PU J B.Diel aqueous chemical cycling in a typical karst spring-fed stream:Controls of biogeochemical processes[J].Acta Geoscientia Sinica,2015,36(2):197-203
[12]张陶,蒲俊兵,袁道先,等.广西官村岩溶溪流中生物地球化学控制的DIC和NO3-昼夜变化研究[J].地质学报,2016,90(8):1965-1976ZHANG T,PU J B,YUAN D X,et al.Biogeochemical controls on daily cycling of DIC and NO3-of Guancun karst stream in Guangxi[J].Acta Geologica Sinica,2016,90(8):1965-1976
[13]李丽,蒲俊兵,李建鸿,等.岩溶地下河补给的地表溪流溶解无机碳及其稳定同位素组成的时空变化[J].环境科学,2017,38(2):527-534LI L,PU J B,LI J H,et al.Temporal and spatial variations of dissolved inorganic carbon and its stable isotopic composition in the surface stream of karst groundwater recharge[J].Environmental Science,2017,38(2):527-534
[14]钟铿,熊天赐,杨锦兰,等.广西壮族自治区柳州市地质系列图集[R].南宁:广西壮族自治区地质矿产局,1988ZHONG K,XIONG T C,YANG J L,et al.Geological Series Atlas of Liuzhou City,Guangxi Zhuang Autonomous Region[R].Nanning:Geological and Mineral Bureau of Guangxi Zhuang Autonomous Region,1988
[15]董海彪,卢文喜,安永凯,等.基于对应分析法的鄂尔多斯盆地东北部地下水污染分析[J].中国环境科学,2015,35(11):3371-3378DONG H B,LU W X,AN Y K,et al.Groundwater pollution assessment in northeastern Ordos basin based on correspondence analysis method[J].China Environmental Science,2015,35(11):3371-3378
[16]WEI Y N,FAN W,WANG W,et al.Identification of nitrate pollution sources of groundwater and analysis of potential pollution paths in loess regions:A case study in Tongchuan Region,China[J].Environmental Earth Sciences,2017,76(12):423
[17]LIU C Q,LI S L,LANG Y C,et al.Usingδ15N-andδ18O-values to identify nitrate sources in karst ground water,Guiyang,southwest China[J].Environmental Science&Technology,2006,40(22):6928-6933
[18]CAO Y J,TANG C Y,SONG X F,et al.Characteristics of nitrate in major rivers and aquifers of the Sanjiang Plain,China[J].Journal of Environmental Monitoring,2012,14(10):2624-2633
[19]梁慧雅,翟德勤,孔晓乐,等.府河-白洋淀硝酸盐来源判定及迁移转化规律[J].中国生态农业学报,2017,25(8):1236-1244LIANG H Y,ZHAI D Q,KONG X L,et al.Sources,migration and transformation of nitrate in Fuhe River and Baiyangdian Lake,China[J].Chinese Journal of Eco-Agriculture,2017,25(8):1236-1244
[20]吴起鑫,韩贵琳,李富山,等.珠江源区南、北盘江丰水期水化学组成特征及来源分析[J].环境化学,2015,34(7):1289-1296WU Q X,HAN G L,LI F S,et al.Characteristic and source analysis of major ions in Nanpanjiang and Beipanjiang at the upper Pearl River during the wet season[J].Environment Chemistry,2015,34(7):1289-1296
[21]LI S L,LIU C Q,LI J,et al.Assessment of the sources of nitrate in the Changjiang River,China using a nitrogen and oxygen isotopic approach[J].Environment Science&Technology,2010,44(5):1573-1578
[22]XING M,LIU W G,WANG Z F,et al.Relationship of nitrate isotopic character to population density in the Loess Plateau of Northwest China[J].Applied Geochemistry,2013,35:110-119
[23]方晶晶.河北平原邯郸地区地下水硝酸盐污染来源及迁移转化过程的多元素同位素及微生物(E.Coil)示踪[D].武汉:中国地质大学,2014FANG J J.Use of multi-isotope and microbial technology(E.coil)for evaluating source and transformation of nitrate in the groundwater in Handan Area in the North China Plain[D].Wuhan:China University of Geosciences,2014
[24]COOK P G,HERCZEG A L.Environmental Tracers in Subsurface Hydrology[M].Boston:Kluwer Academic Publishers,2000:80-90
[25]史婷婷,陈植华,张卫.湖北宜昌香溪河流域环境同位素特征及其水循环意义[J].地质科技情报,2012,31(6):161-167SHI T T,CHEN Z H,ZHANG W.Characteristics of environmental isotopes in Xiangxi River basin of Yichang,Hubei Province and its significance for hydrological cycle[J].Geological Science and Technology Information,2012,31(6):161-167
[26]张小娟,宋维峰,吴锦奎,等.元阳梯田水源区土壤水氢氧同位素特征[J].环境科学,2015,36(6):2102-2108ZHANG X J,SONG W F,WU J K,et al.Characteristics of hydrogen and oxygen isotopes of soil water in the water source area of Yuanyang terrace[J].Environmental Science,2015,36(6):2102-2108