Denitrification Rate in Aquifer Based on In-Situ Pumping/Injecting Test and Isotope Technique
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摘要: 反硝化作用是地下水硝酸盐污染去除最重要的过程.由于水文地质条件和水文地球化学环境的复杂性和不确定性，精准测定含水层反硝化速率是反硝化过程的研究难点.选取潮白河冲洪积扇中部中国环境科学研究院地下水创新野外基地作为研究区，基于野外原位试验和15N同位素示踪法提出一种含水层反硝化速率的测定方法.该方法综合体现了研究区实际水文地质条件和水文地球化学环境对反硝化作用的影响，并充分考虑了硝酸盐在含水层中稀释弥散作用对计算结果的影响.结果表明：①潮白河冲洪积扇中部某地地下26~28 m处于还原环境，含水介质以粉细砂为主，ρ（NO3-N）平均值为2.77 mg/L.②地下26~28 m反硝化速率在349.52~562.99 μg/（kg·d）（以N计，下同）之间，平均值为450.31 μg/（kg·d）.通过与研究区含水介质、采样深度和硝酸盐背景值相似的国内外案例对比研究，初步评估结果处于合理区间.③测试结果具有一定不确定性，主要来自忽略中间产物NO2-和NO的计算方法、扰动采样方法、N2O的操作规范程度及采样频率等方面.研究方法为测定含水层硝酸盐速率研究提供了新的思路，研究结果可为地下水中硝酸盐转化过程机理研究、地下水硝酸盐污染修复及风险管控提供关键的理论支撑数据.Abstract: Denitrification process of nitrate in aquifers is vital because it can dissipate groundwater nitrate pollution. It is very difficult to acquire the accurate denitrification rate in the aquifer due to the complicated hydrogeological conditions and hydrogeochemical environment in the field. A method was proposed for determining the denitrification rate in the aquifer based on in-situ pumping/injecting test and isotope technique. The method was applied in the groundwater innovation field base of Chinese Research Academy of Environmental Sciences, in the middle of the Chaobai River alluvial-proluvial fan. The method integrated the effect of actual hydrogeological conditions and hydrogeochemical environment on the denitrification process, as well as the effect of dilution and dispersion of nitrate in the aquifer. The results showed that the shallow aquifer, which was composed by sandy loam, was in the reducing environments at the depth of 26-28 m in the study area. The average nitrate concentration was 2.77 mg/L. The denitrification rates ranged between 349.52 and 562.99 μg/(kg·d) with the average value of 450.31 μg/(kg·d). The values were preliminarily verified to be reasonable by comparative study of domestic and foreign cases in the study area. The method of ignoring the intermediate products of NO2- and NO, perturbation sampling method, operation specification degree of N2O and sampling frequency can result in the uncertainty of the denitrification rates. The method can objectively and quantitatively determine the denitrification intensity in the aquifer as a new idea. The research results can provide key data for studying the mechanism of nitrate fate and transport in the aquifer, and remediation and risk control of groundwater nitrate pollution.
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图 3 野外原位注抽试验技术原理
注：1表示将地下水抽出到储水箱的过程；2表示加入同位素标记的KNO3(15N)和KBr药剂；3表示向储水箱中注入N2；4表示将储水箱中的井水混合溶液注入地下水井；5表示再次抽出地下水进行采样；6表示将水样进行部分氦气置换后放到平衡振荡器中；7表示用集气袋收集反硝化反应气体产物. Ⅰ表示混合溶液小范围扩散至含水层地下水中；Ⅱ表示混合溶液进入含水层地下水的范围进一步扩大；Ⅲ表示不受混合溶液影响区域.
Figure 3. Schematic diagram of in-situ pumping/injecting test
图 4 单井处示踪剂、反应物和生成物的标准浓度穿透曲线
注：C0为注入时初始测试溶液浓度；C为注入一段时间后测试溶液和地下水混合溶液的浓度.
Figure 4. Concentration breakthrough curve of tracers, reactants and products in the singe well
图 5 试验井中示踪剂、残留物和生成物的浓度穿透曲线
Figure 5. Concentration breakthrough curve of tracers, residues and products in the test wells
表 1 含水介质理化性质和地球化学环境指标测试结果
Table 1. Physicochemical properties and geochemistry indexes in the phreatic aquifer
试验井编号 试验井深度/
mpH 砂粒/
%粉砂粒/
%黏粒/
%ρ(DO)/
(mg/L)Eh/mV ρ(TOC)/
(mg/L)ρ(NH4+-N)/
(mg/L)ρ(NO3-N)/
(mg/L)ρ(NO2-N)/
(mg/L)ρ(Br-)/
(mg/L)土粒密度/
(g/cm3)1# 26.3 7.71 84.5 1.4 14.1 1.26 94.3 3.28 1.53 3.42 0.024 1 4.31 2.52 2# 27.1 7.92 78.9 8.3 12.8 0.53 81.5 3.87 1.23 2.02 0.018 9 3.89 2.41 3# 27.7 7.83 77.2 8.5 14.3 2.05 100.6 3.06 1.68 2.86 0.023 4 3.32 2.67 平均值 27.0 7.82 80.2 6.1 13.7 1.28 92.1 3.74 1.48 2.77 0.022 1 3.84 2.53 
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表 2 试验井中不同时间抽注水量和各物质浓度
Table 2. Pumping/injection volume and concentrations of tracers, reactants and products at different times in the testing wells
试验井编号 时刻 累计抽水量/L 累计注水量/L ρ(Br-)/(mg/L) ρ(NO3-)/(mg/L) ρ(15N2O-N+15N2-N)/(μg/L) 初始 0 30 20.00 20.00 1.00 18:00 2.5 30 12.90 11.55 0.00 21:00 5.0 30 14.35 12.50 0.09 00:00 7.5 30 15.45 13.20 0.07 1# 06:00 10.0 30 15.86 12.90 0.12 09:00 12.5 30 15.85 12.40 0.08 12:00 15.0 30 12.50 7.50 0.27 14:00 17.5 30 12.30 6.45 0.15 16:00 20.0 30 11.70 5.50 0.06 19:00 22.5 30 11.40 4.85 0.06 初始 0 30 20.00 20.00 1.00 19:30 2.5 30 13.80 10.40 0.00 22:00 5.0 30 15.60 11.60 0.10 01:00 7.5 30 16.95 12.80 0.03 2# 06:00 10.0 30 17.70 13.21 0.06 09:00 12.5 30 18.90 14.10 0.06 12:00 15.0 30 14.40 8.00 0.27 14:00 17.5 30 14.04 7.60 0.01 16:00 20.0 30 13.50 6.70 0.06 19:00 22.5 30 11.25 4.40 0.01 初始 0 30 20.00 20.00 1.00 20:00 2.5 30 9.80 8.40 0.00 22:00 5.0 30 13.80 11.80 0.10 01:00 7.5 30 15.00 12.30 0.12 3# 06:00 10.0 30 19.20 16.20 0.05 09:00 12.5 30 15.90 12.10 0.14 12:00 15.0 30 14.92 10.85 0.05 14:00 17.5 30 14.50 10.40 0.01 16:00 20.0 30 11.80 7.60 0.02 19:00 22.5 30 11.25 7.00 0.01
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表 3 试验井反硝化速率计算过程与结果
Table 3. Data summary for denitrification rate in the test wells
试验井编号 t1 t2 ρ(NO3-N)t1/
(mg/L)ρ(NO3-N)t2/
(mg/L)ρ(Br-)t1/
(mg/L)ρ(Br-)t2/
(mg/L)M/μg DMs/kg Fdil T′/d Rdef
/[μg/(kg·d)]1# 09:00 12:00 12.4 7.5 15.85 12.5 676.2 15.67 1.27 0.125 438.43 2# 09:00 12:00 14.1 8.0 18.90 14.4 841.8 15.67 1.31 0.125 562.99 3# 06:00 09:00 16.2 12.1 19.20 15.9 565.8 15.67 1.21 0.125 349.52
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表 4 野外抽注试验测定的地下水反硝化速率[3]
Table 4. Groundwater denitrification intensity measured by field experiment[3]
取样地点 土地利用类型 含水介质类型 取样深度/m 初始ρ(NO3--N)/(mg/L) 反硝化速率/[μg/(kg·d)] 加入试剂情况 持续时间 爱尔兰 草地 砂砾石夹黏土、冰堆物 5 4.7 10.9±3.5 20 L井水(注入SF6气体，含20 mg/L KBr、20 mg/L 15N标记的KNO3) 注入1~2 h(10~15 L/h)，培养6 h，抽出1~2 h(10~15 L/h) 砂岩、页岩 12 2 470±111 砂岩、页岩夹少量石英岩 22 2.9 9.2±2.8 爱尔兰 耕地 砂砾石、黏土夹层、冰堆物 5 12.8 3.8±0.7 20 L井水(注入SF6气体，含20 mg/L KBr、20 mg/L 15N标记的KNO3) 注入1~2 h(10~15 L/h)，培养6 h，抽出1~2 h(10~15 L/h) 风化灰岩 12 10.4 6.4±1.8 石灰岩(有断层) 22 12.6 1.4±0.4 美国 河岸带湿地 细泥砂、淤泥、砂 0.03~0.25 0.1~11 0.1~193 10 L地下水(含32 mg/L 15N标记的KNO3、100 μg/L SF6) 注入约1 h(16 L/h)，培养4~5 h，抽出约1 h(6 L/h) 美国 湿地 砂壤土、粗壤 0.65、1.5、3 0.6~1.4 1~330 10 L井水(含32 mg/L 15N标记的KNO3、100 μg/L SF6) 注入约1 h(160 mL/min)，培养22~24 h，抽出约1 h(0.5 L/次) 美国Tanyard Brook 溪岸带 壤砂土 0.65 0.4 96.7±19.7 10 L井水(含32 mg/L 15N标记的KNO3、32 mg/L KBr、100 μg/L SF6) 注入约1 h(10~12 L/h)，培养72 h，抽出约1 h(9~13 L/h) 美国Brushneck Cove 海岸带沼泽 细砂 1.25 0 123.2±63.8 10 L井水(含32 mg/L 15N标记的KNO3、100 μg/L SF6) 注入约1 h(10~12 L/h)，培养5 h，抽出约1 h(9~13 L/h) 加拿大Rodney 耕地 砂 3 13 190~3 100 200 L井水(含13.0 mg/L KNO3、5.06 mg/L NaBr) 356 h 荷兰西部 — 粗砂夹碎石 26 2.1±0.2 120~200 3×109 m3水 7 a 44 2.1±0.2 90~150 加拿大Rodney 耕地 砂 1 6.4 580 抽出的井水中加入足够的NO3-N，并充入C2H2 10 d 美国Utah — 黏土、粉土夹鹅卵石 3.5 12.5、23.7 730 — —
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[1] NAKAGAWA K, AMANO H, TAKAO Y, et al.On the use of coprostanol to identify source of nitrate pollution in groundwater[J].Journal of Hydrology, 2017, 550:663-668. doi: 10.1016/j.jhydrol.2017.05.038 [2] 王仕琴, 郑文波, 孔晓乐.关于华北农区浅层地下水硝酸盐污染的几点认识[J].中国生态农业学报, 2018.doi: 10.13930/j.cnki.cjea.180639.WANG Shiqin, ZHENG Wenbo, KONG Xiaole.Review of nitrate contamination of shallow groundwater in agricultural area of the North China Plain[J].Chinese Journal of Eco-Agriculture, 2018.doi: 10.13930/j.cnki.cjea.180639. [3] 郇环, 张军军, 杨昱, 等.基于整合分析法的地下水反硝化强度研究[J].农业环境科学学报, 2019, 38(7):1597-1606. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=nyhjbh201907021HUAN Huan, ZHANG Junjun, YANG Yu, et al.Groundwater denitrification intensity based on an integrated analysis method[J].Journal of Agro-Environment Science, 2019, 38(7):1597-1606. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=nyhjbh201907021 [4] HINSHAW S E, TATARIW C, FLOURNOY N, et al.Vegetation loss decreases salt marsh denitrification capacity:implications for marsh erosion[J].Environmental Science & Technology, 2017, 51(15):8245-8253. https://www.ncbi.nlm.nih.gov/pubmed/28616973 [5] IRIBAR A, HALLIN S, PÉREZ J M S, et al.Potential denitrification rates are spatially linked to colonization patterns of nosZ genotypes in an alluvial wetland[J].Ecological Engineering, 2015, 80:191-197. doi: 10.1016/j.ecoleng.2015.02.002 [6] CLAGUE J C, STENGER R, CLOUGH T J.Denitrification in the shallow groundwater system of a lowland catchment:a laboratory study[J].Catena, 2015, 131:109-118. doi: 10.1016/j.catena.2015.03.012 [7] WEYMANN D, GEISTLINGER H, WELL R, et al.Kinetics of N2O production and reduction in a nitrate-contaminated aquifer inferred from laboratory incubation experiments[J].Biogeosciences, 2010, 7(6):1953-1972. doi: 10.5194/bg-7-1953-2010 [8] GARRARD N.A stable isotope and hydrochemical approach to examining denitrification along a shallow groundwater-surface water continuum in an agriculturally-impacted catchment[D].Norwich: University of East Anglia, 2019. [9] BERNARD-JANNIN L, SUN X, TEISSIER S, et al.Spatio-temporal analysis of factors controlling nitrate dynamics and potential denitrification hot spots and hot moments in groundwater of an alluvial floodplain[J].Ecological Engineering, 2017, 103:372-384. doi: 10.1016/j.ecoleng.2015.12.031 [10] KOROM S F.Natural denitrification in the saturated zone:a review[J].Water Resources Research, 1992, 28(6):1657-1668. doi: 10.1029/92WR00252 [11] 郭志英, 贾仲君.中国典型生态系统土壤硝化强度的整合分析[J].土壤学报, 2014, 51(6):1317-1324. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=trxb201406016GUO Zhiying, JIA Zhongjun.Meta-analysis of soil nitrification activity in ecosystems typical of China[J].Acta Pedologica Sinica, 2014, 51(6):1317-1324. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=trxb201406016 [12] 王宁宁, 薛冬梅, 王义东, 等.自然生态系统中厌氧氨氧化和反硝化耦合反应研究进展[J].环境科学研究, 2018, 31(4):616-627. http://www.hjkxyj.org.cn/hjkxyj/ch/reader/view_abstract.aspx?file_no=20180404&flag=1WANG Ningning, XUE Dongmei, WANG Yidong, et al.A review of anammox-denitrification coupling process in a natural ecosystem[J].Research of Environmental Sciences, 2018, 31(4):616-627. http://www.hjkxyj.org.cn/hjkxyj/ch/reader/view_abstract.aspx?file_no=20180404&flag=1 [13] 周梦娟, 缪恒锋, 陆震明, 等.碳源对反硝化细菌的反硝化速率和群落结构的影响[J].环境科学研究, 2018, 31(12):2047-2054. http://www.hjkxyj.org.cn/hjkxyj/ch/reader/view_abstract.aspx?file_no=20181208&flag=1ZHOU Mengjuan, MIAO Hengfeng, LU Zhenming, et al.The influence of different carbon sources on denitrification rate and community structure of denitrifying bacteria[J].Research of Environmental Sciences, 2018, 31(12):2047-2054. http://www.hjkxyj.org.cn/hjkxyj/ch/reader/view_abstract.aspx?file_no=20181208&flag=1 [14] JAHANGIR M M R, FENTON O, MÜLLER C, et al.In situ denitrification and DNRA rates in groundwater beneath an integrated constructed wetland[J].Water research, 2017, 111:254-264. doi: 10.1016/j.watres.2017.01.015 [15] NGUYEN V, PARK Y, YU J, et al.Bioelectrochemical denitrification on biocathode buried in simulated aquifer saturated with nitrate-contaminated groundwater[J].Environmental Science & Pollution Research, 2016, 23(15):15443-15451. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=c6384ac584dbb8acaef3f624e2449ef3 [16] RIVETT M O, BUSS S R, MORGAN P, et al.Nitrate attenuation in groundwater:a review of biogeochemical controlling processes[J].Water research, 2008, 42(16):4215-4232. doi: 10.1016/j.watres.2008.07.020 [17] JAHANGIR M M R, JOHNSTON P, ADDY K, et al.Quantification of in situ denitrification rates in groundwater below an arable and a grassland system[J].Water, Air, & Soil Pollution, 2013, 224(9):1693-1707. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=80d06c1e5e04792abffda53673dd27af [18] ZHU Q, WEN Z, LIU H.Microbial effects on hydraulic conductivity estimation by single-well injection tests in a petroleum-contaminated aquifer[J].Journal of Hydrology, 2019, 573:352-364. doi: 10.1016/j.jhydrol.2019.03.031 [19] BURBERY L.Nitrate reactivity in groundwater:a brief review of the science, practical methods of assessment, and collation of results from New Zealand field investigations[J].Journal of Hydrology, 2018, 57(2):41-69. [20] BURBERY L F, FLINTOFT M J, CLOSE M E.Application of the re-circulating tracer well test method to determine nitrate reaction rates in shallow unconfined aquifers[J].Journal of contaminant hydrology, 2013, 145:1-9. doi: 10.1016/j.jconhyd.2012.11.006 [21] CLAGUE J C, STENGER R, CLOUGH T J.Denitrification in the shallow groundwater system of a lowland catchment:a laboratory study[J].Catena, 2015, 131:109-118. doi: 10.1016/j.catena.2015.03.012 [22] WARNEKE S, SCHIPPER L A, BRUESEWITZ D A, et al.A comparison of different approaches for measuring denitrification rates in a nitrate removing bioreactor[J].Water Research, 2011, 45(14):4141-4151. doi: 10.1016/j.watres.2011.05.027 [23] CLOUGH T J, ADDY K, KELLOGG D Q, et al.Dynamics of nitrous oxide in groundwater at the aquatic-terrestrial interface[J].Global Change Biology, 2007, 13(7):1528-1537. doi: 10.1111/j.1365-2486.2007.01361.x [24] HARRISON M D, GROFFMAN P M, MAYER P M, et al.Denitrification in alluvial wetlands in an urban landscape[J].Journal of Environment Quality, 2011, 40(2):634-646. doi: 10.2134/jeq2010.0335 [25] JURADO A, BORGES A V, BROUYÈRE S.Dynamics and emissions of N2O in groundwater:a review[J].Science of the Total Environment, 2017, 584:207-218. [26] 翟远征, 王金生, 周俊.北京市潮白河冲洪积扇地下水流动和更新模式的水化学和同位素标记[J].应用基础与工程科学学报, 2013, 21(1):32-44. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=yyjcygckxxb201301004ZHAI Yuanzheng, WANG Jisheng, ZHOU Jun.Hydrochemical and isotopic markers of flow patterns and renewal mode of groundwater in Chaobai River alluvial fan in Beijing[J].Journal of Basic Science and Engineering, 2013, 21(1):32-44. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=yyjcygckxxb201301004 [27] 张宇, 黄鹤, 吕军, 等.潮白河冲洪积扇地质结构与地下水库动态模拟研究[J].东北水利水电, 2019, 11:51-53. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dbslsd201911021ZHANG Yu, HUANG He, LV Jun, et al.Study on geological structure and groundwater reservoir dynamic simulation of Chaobaihe alluvial and diluvial fan[J].Water Resources & Hydropower of Northeast, 2019, 11:51-53. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dbslsd201911021 [28] 郇环.海河流域地下水调蓄区污染风险源识别与阻控技术研究子课题结题验收报告[R].北京: 中国环境科学研究院, 2017: 35-36. [29] 姜永海.地下水硝酸盐污染阻断与修复技术及装备研究技术总结报告[R].北京: 中国环境科学研究院, 2014: 10-13. [30] FIRESTONE M K, FIRESTONE R B, TIEDJE J M.Nitrous oxide from soil denitrification factors controlling its biological production[J].Science, 1980, 206:749-751. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=3213dccf4b8ac418aa4a1be51ff80b82 [31] ESCHENBACH W, WELL R.Predicting the denitrification capacity of sandy aquifers from shorter-term incubation experiments and sediment properties[J].Biogeosciences, 2013, 10(2):1013-1035. doi: 10.5194/bg-10-1013-2013 [32] ESCHENBACH W, WELL R, WALTHER W.Predicting the denitrification capacity of sandy aquifers from in situ measurements using push-pull 15N tracer tests[J].Biogeosciences, 2015, 12(8):2327-2346. doi: 10.5194/bg-12-2327-2015 -
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