Abstract
This study contributes to identifying and spatializing the different types of nitrate sources by combining hydrogeochemical and isotopic data with principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE) multicriteria statistical methods. The methodology is applied to the strategic Mons Basin chalk aquifer (Belgium). The results are based on a whole dataset containing 72 water samples with analyses of the hydrogeochemical parameters (temperature, pH, electrical conductivity (EC), redox potential, dissolved O2), alkalinity, total organic carbon (TOC), silica (SiO2), major and minor ions (NO3–, NH4+, Ca2+, dissolved Fe and Mn, K+, Mg2+, Na+, Sr2+, Cl–, F–, SO4–, B) and multiple stable isotope ratios (δ11B, δ15N–NO3–, δ18O–NO3–). Compared to classical PCA, the recently developed t-SNE method, which considers nonlinear relationships between variables and preserves local-scale similarities in a low-dimensional space, showed much better performance in discriminating different groups of samples and related zones in the aquifer. t-SNE results combined with isotope ratios highlighted four zones in the aquifer (grouped as A–D) and the presence of denitrification fronts. Group A presents a manure signature (δ15N–NO3– – mean (μ) +12.78‰, standard deviation (σ) 6.48‰; δ11B – μ 29.96‰, σ 6.91‰). Group B exhibits both manure and inorganic fertilizer signatures (δ15N–NO3– – μ 6.27‰, σ 2.55‰; δ11B – μ 15.86‰, σ 9.69‰). Group C shows a contamination by sewage (δ15N–NO3– – μ 12.67‰, σ 5.60‰; δ11B – μ 9.97‰, σ 7.08‰). Group D presents a mixed signature (δ15N–NO3– – μ 9.25‰, σ 2.94‰; δ11B – μ 20.00‰, σ 6.70‰).
Résumé
Cette étude contribue à l’identification et à la spatialisation de différents types de sources de nitrates en combinant des données hydrogéochimiques et isotopiques avec des méthodes statistiques multicritères d’analyse en composantes principales (ACP) et de réduction de dimensionnalité visuelle t-SNE (Stochastic Neighbor Embedding). La méthodologie est appliquée à l’aquifère stratégique de la craie du bassin de Mons (Belgique). Les résultats sont basés sur un ensemble de données contenant 72 échantillons d’eau comprenant des analyses des paramètres hydrogéochimiques (température, pH, conductivité électrique (EC), potentiel redox, O2 dissous), de l’alcalinité, du Carbone Organique Total (COT), de la silice (SiO2), des ions majeurs et mineurs ((NO3–, NH4+, Ca2+, Fe et Mn dissous, K+, Mg2+, Na+, Sr2+, Cl–, F–, SO4–, B) et plusieurs rapports d’isotopes stables (δ11B, δ15N–NO3–, δ18O–NO3–). Par rapport à l’ACP classique, la méthode t-SNE récemment développée, qui prend en compte les relations non linéaires entre les variables et préserve les similitudes à l’échelle locale dans un espace de faible dimension, a montré de bien meilleures performances dans la discrimination de différents groupes d’échantillons et de zones apparentées dans l’aquifère. Les résultats t-SNE combinés aux rapports isotopiques ont mis en évidence quatre zones dans l’aquifère (regroupées de A à D) et la présence de fronts de dénitrification. Le groupe A présente une signature correspondant à de l’épandage de fumier (δ15N–NO3– – moyenne (μ) +12.78‰, écart-type(σ) 6.48‰ ; δ11B – μ 29.96‰, σ 6.91‰). Le groupe B présente à la fois des signatures d’épandage de fumier ou d’engrais (δ15N–NO3– – μ 6.27‰, σ 2.55‰; δ11B – μ 15.86‰, σ 9.69‰). Le groupe C présente une contamination par les eaux usées (δ15N–NO3– – μ 12.67‰, σ 5.60‰; δ11B – μ 9.97‰, σ 7.08‰). Le groupe D présente une signature mixte (δ15N–NO3– – μ 9.25‰, σ 2.94‰; δ11B – μ 20.00‰, σ 6.70‰).
Resumen
Este estudio contribuye a identificar y localizar espacialmente los distintos tipos de fuentes de nitratos mediante la combinación de datos hidrogeoquímicos e isotópicos con métodos estadísticos multicriterio de análisis de componentes principales (ACP) y de incrustación estocástica de los vecinos distribuidos en t (t-SNE). La metodología se aplica al estratégico acuífero calcáreo de la cuenca de Mons (Bélgica). Los resultados se basan en un conjunto de datos que contiene 72 muestras de agua con análisis de los parámetros hidrogeoquímicos (temperatura, pH, conductividad eléctrica (CE), potencial redox, O2 disuelto), alcalinidad, carbono orgánico total (COT), sílice (SiO2), iones mayores y menores (NO3–, NH4+, Ca2+, Fe y Mn disueltos, K+, Mg2+, Na+, Sr2+, Cl–, F–, SO4–, B) y múltiples relaciones de isótopos estables (δ11B, δ15N–NO3–, δ18O–NO3–). En comparación con el ACP clásico, el método recientemente desarrollado t-SNE, que tiene en cuenta las relaciones no lineales entre variables y preserva las similitudes a escala local en un espacio de baja dimensión, mostró un rendimiento mucho mejor a la hora de discriminar diferentes grupos de muestras y zonas relacionadas en el acuífero. Los resultados del t-SNE combinados con las relaciones isotópicas pusieron de manifiesto cuatro zonas en el acuífero (agrupadas de la A a la D) y la presencia de frentes de desnitrificación. El grupo A presenta una firma de abono (δ15N–NO3– - media (μ) +12.78‰, desviación estándar (σ) 6.48‰; δ11B - μ 29.96‰, σ 6.91‰). El grupo B muestra firmas tanto de abono como de fertilizante inorgánico (δ15N–NO3– - μ 6.27‰, σ 2.55‰; δ11B - μ 15.86‰, σ 9.69‰). El grupo C muestra una contaminación por aguas residuales (δ15N–NO3– - μ 12.67‰, σ 5.60‰; δ11B - μ 9.97‰, σ 7.08‰). El grupo D presenta una firma mixta (δ15N–NO3– - μ 9.25‰, σ 2.94‰; δ11B – μ 20.00‰, σ 6.70‰).
摘要
通过将水文地球化学和同位素数据与主成分分析(PCA)和t分布随机邻域嵌入(t-SNE)多准则统计方法相结合,本研究进行了识别和划定了硝酸盐来源的不同类型。该方法应用于比利时战略性的Mons盆地白垩系含水层。结果基于包含72个水样的整个数据集,分析了水文地球化学参数(温度、pH值、电导率(EC)、氧化还原电位、溶解氧)、碱度、总有机碳(TOC)、硅(SiO2)、主要和次要离子(NO3–,NH4+,Ca2+,溶解Fe和Mn,K+,Mg2+,Na+,Sr2+,Cl–,F–,SO4–,B)以及多种稳定同位素比值(δ11B,δ15N–NO3–,δ18O–NO3–)。与传统的PCA方法相比,最近开发的t-SNE方法考虑变量之间的非线性关系,并保留低维空间中的局部相似性,能够更好地区分不同样品组和含水层中的相关区域。t-SNE结果与同位素比值结合,突出了含水层中的四个区域(分为A至D组)和反硝化前缘的存在。A组呈现出肥料特征(δ15N–NO3– - 平均值(μ)+12.78‰,标准偏差(σ)6.48‰;δ11B – μ 29.96‰,σ 6.91‰)。B组展示了肥料和无机肥料特征(δ15N–NO3– – μ 6.27‰,σ 2.55‰;δ11B – μ 15.86‰,σ 9.69‰)。C组显示污水污染(δ15N–NO3– – μ 12.67‰,σ 5.60‰;δ11B – μ 9.97‰,σ 7.08‰)。D组呈现出混合特征(δ15N–NO3– – μ 9.25‰,σ 2.94‰;δ11B – μ 20.00‰,σ 6.70‰)。
Resumo
Este estudo contribui para identificar e espacializar os diferentes tipos de fontes de nitrato, combinando dados hidrogeoquímicos e isotópicos com métodos estatísticos multicritério de análise de componentes principais (ACP) e distribuição estocástica de vizinhança t-distribuída (t-SNE). A metodologia é aplicada ao estratégico aquífero calcário da Bacia de Mons (Bélgica). Os resultados são baseados em um conjunto de dados completo contendo 72 amostras de água com análises dos parâmetros hidrogeoquímicos (temperatura, pH, condutividade elétrica (CE), potencial redox, O2 dissolvido), alcalinidade, carbono orgânico total (COT), sílica (SiO2), íons maiores e menores (NO3–, NH4+, Ca2+, Fe e Mn dissolvidos, K+, Mg2+, Na+, Sr2+, Cl–, F–, SO4–, B) e múltiplas razões isotópicas estáveis (δ11B, δ15N–NO3–, δ18O–NO3–). Comparado à ACP clássica, o método t-SNE desenvolvido recentemente, que considera relações não lineares entre variáveis e preserva semelhanças de escala local em um espaço de baixa dimensão, mostrou desempenho muito melhor em discriminar diferentes grupos de amostras e zonas relacionadas no aquífero. Os resultados do t-SNE combinados com as razões isotópicas destacaram quatro zonas no aquífero (agrupadas como A a D) e a presença de frentes de desnitrificação. O grupo A apresenta uma assinatura de esterco (δ15N–NO3– – média (μ) +12.78‰, desvio padrão (σ) 6.48‰; δ11B – μ 29.96‰, σ 6.91‰). O Grupo B exibe assinaturas de esterco e fertilizantes inorgânicos (δ15N–NO3– – μ 6.27‰, σ 2.55‰; δ11B – μ 15.86‰, σ 9.69‰). O grupo C apresenta uma contaminação por esgoto (δ15N–NO3– – μ 12.67‰, σ 5.60‰; δ11B – μ 9.97‰, σ 7.08‰). O grupo D apresenta assinatura mista (δ15N–NO3– – μ 9.25‰, σ 2.94‰; δ11B – μ 20.00‰, σ 6.70‰).
Similar content being viewed by others
References
Abascal E, Gómez-Coma L, Ortiz I, Ortiz A (2022) Global diagnosis of nitrate pollution in groundwater and review of removal technologies. Sci Total Environ 810:152233. https://doi.org/10.1016/j.scitotenv.2021.152233
Accoe F, Berglund M, Duta S, Hennessy C, Taylor P, Van Hoof K, De Smedt S (2008) Source apportionment of nitrate pollution in surface water using stable isotopes of N and O in nitrate and B: a case study in Flanders (Belgium). JRC Scientific and Technical Reports, Joint Research Centre, Geel, Belgium, 25 pp
Appelo, CAJ, Postma D (2004) Redox processes. In: Geochemistry, groundwater and pollution. CRC, Boca Raton, FL, pp 415–487
Aravena R, Evans M, Cherry J (1993) Stable isotopes of oxygen and nitrogen in source identification of nitrate from septic systems. Groundwater 31:180–186
Atteia O (2015) Chimie et pollution des eaux souterraines [Groundwater chemistry and pollution]. Tec & Doc. Lavoisier, Paris
Balzani L, Orban P, Brouyère S (2022) Protection of peri-urban groundwater catchments: a multi-tracer approach for the identification of urban pollution sources. Presented at the EGU General Assembly 2022, Vienna, May 2022
Bassett R, Buszka P, Davidson G, Chong-Diaz D (1995) Identification of groundwater solute sources using boron isotopic composition. Environ Sci Technol 29:2915–2922. https://doi.org/10.1021/es00012a005
Bastien J, Roland S, Rorive A (2017) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Planchettes Binche – Morlanwelz no. 46/5-6, SPW, Wallonia, Belgium
Biddau R, Cidu R, Da Pelo S, Carletti A, Ghiglieri G, Pittalis D (2019) Source and fate of nitrate in contaminated groundwater systems: assessing spatial and temporal variations by hydrogeochemistry and multiple stable isotope tools. Sci Total Environ 647:1121–1136
Bock H-H (2007) Clustering methods: a history of k-means algorithms. In: Brito P, Cucumel G, Bertrand P, de Carvalho F (eds) Selected contributions in data analysis and classification. Springer, Heidelberg, Germany, pp 161–172. https://doi.org/10.1007/978-3-540-73560-1_15
Böhlke JK, Denver JM (1995) Combined use of groundwater dating, chemical, and isotopic analyses to resolve the history and fate of nitrate contamination in two agricultural watersheds, Atlantic Coastal Plain, Maryland. Water Resour Res 31:2319–2339. https://doi.org/10.1029/95WR01584
Böttcher J, Strebel O, Voerkelius S, Schmidt H-L (1990) Using isotope fractionation of nitrate-nitrogen and nitrate-oxygen for evaluation of microbial denitrification in a sandy aquifer. J Hydrol 114:413–424. https://doi.org/10.1016/0022-1694(90)90068-9
Bougard G, Roland S, Rorive A (2017) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Planchettes Quiévrain – Saint-Ghislain no. 45/5-6, SPW, Wallonia, Belgium
Bronders J, Tirez K, Desmet N, Widory D, Petelet-Giraud E, Bregnot A, Boeckx P (2012) Use of compound-specific nitrogen (d15N), oxygen (d18O), and bulk boron (d11B) isotope ratios to identify sources of nitrate-contaminated waters: a guideline to identify polluters. Environ Forensics 13:32–38. https://doi.org/10.1080/15275922.2011.643338
Brouyère S, Balzani L, Orban P (2022) The CASPER project: an integrated approach for pollution risk assessment in peri-urban groundwater catchment areas. Copernicus Meetings. https://doi.org/10.5194/adgeo-59-45-2022
Canter LW (2019) Nitrates in groundwater. Routledge, Abingdon-on-Thames, UK
Chen DJZ, MacQuarrie KTB (2005) Correlation of δ15N and δ18O in NO3– during denitrification in groundwater. J Environ Eng Sci 4:221–226. https://doi.org/10.1139/S05-002
Czekaj J, Jakóbczyk-Karpierz S, Rubin H, Sitek S, Witkowski AJ (2016) Identification of nitrate sources in groundwater and potential impact on drinking water reservoir (Goczałkowice Reservoir, Poland). Phys Chem Earth Parts ABC 94:35–46
Di HJ, Cameron KC (2002) Nitrate leaching in temperate agroecosystems: sources, factors and mitigating strategies. Nutr Cycl Agroecosyst 64:237–256. https://doi.org/10.1023/A:1021471531188
Domenico PA, Schwartz FW (1997) Physical and chemical hydrogeology, 2nd edn. Wiley, New York
Duan L, Wu Y, Fan J, Ye F, Xie C, Fu X, Sun Y (2022) Identification of nitrogen pollution sources and transport transformation processes in groundwater of different landforms using C, H, N, and O isotope techniques: an example from the lower Weihe River. Environ Sci Pollut Res. https://doi.org/10.1007/s11356-022-24337-2
EEA C (2018) Corine land cover (CLC) 2018, version 2020_20u1. https://land.copernicus.eu/pan-european/corine-land-cover/clc2018. Accessed May 2023
Fan AM, Steinberg VE (1996) Health implications of nitrate and nitrite in drinking water: an update on methemoglobinemia occurrence and reproductive and developmental toxicity. Regul Toxicol Pharmacol 23:35–43. https://doi.org/10.1006/rtph.1996.0006
Gamble A, Babbar-Sebens M (2011) On the use of multivariate statistical methods for combining in-stream monitoring data and spatial analysis to characterize water quality conditions in the White River Basin, Indiana, USA. Environ Monit Assess 184:845–875. https://doi.org/10.1007/s10661-011-2005-y
Gouvernement Wallon (2016) Code de l’Eau [Water Code], Annexe XIV, [A.G.W. 03.05.2007] [A.G.W. 12.02.2009], Evaluation de la qualité des masses d’eay souterraine [Evaluation of the quality of undergound water]. Gouvernement Wallon, Wallonia, Belgium
Habils F, Roland S, Rorive A (2017a) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Planchettes Beloeil – Baudour no. 45/1-2, SPW, Wallonia, Belgium
Habils F, Roland S, Rorive A (2017b) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Planchettes Jurbise – Obourg no. 45/3-4, SPW, Wallonia, Belgium
Habils F, Roland S, Rorive A (2018) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Planchettes Le Roeulx – Seneffe no. 46/1-2, SPW, Wallonia, Belgium
Hartigan JA (1975) Clustering algorithms, 99th edn. Wiley, Chichester, UK
Hartigan JA, Wong MA (1979) A K-means clustering algorithm. J R Stat Soc Ser C Appl Stat 28:100–108. https://doi.org/10.2307/2346830
Heaton TH (1986) Isotopic studies of nitrogen pollution in the hydrosphere and atmosphere: a review. Chem Geol Isot Geosci Sect 59:87–102
Hinton GE, Roweis S (2002) Stochastic neighbor embedding. In: Becker S, Thrun S, Obermayer K (eds) Advances in neural information processing systems. MIT Press, Cambridge, MA
Hiscock K, Lloyd J, Lerner D (1991) Review of natural and artificial denitrification of groundwater. Water Res 25:1099–1111
IDEA (2015) CHYDRO-004 – Délimitation des zones de prévention du puits BRASSICO à GHLIN (MONS) [Delimitation of the protection zones of the BRASSICO well in GHLIN (Mons)]. SPW, Wallonia, Belgium
ISSEP (2014) Compendium Wallon d’échantillonnage et d’analyses, méthode de prélèvement des eaux souterraines dans les aquifères non superficiels [Walloon compendium of sampling and analysis methods]. ISSEP, Liege, Belgium
Jackson B, Browne C, Butler A, Peach D, Wade AJ, Wheater H (2008) Nitrate transport in Chalk catchments: monitoring, modelling and policy implications. Environ Sci Policy 11:125–135
Kaown D, Koh D-C, Mayer B, Mahlknecht J, Ju Y, Rhee S-K, Kim J-H, Park DK, Park I, Lee H-L, Yoon Y-Y, Lee K-K (2023) Estimation of nutrient sources and fate in groundwater near a large weir-regulated river using multiple isotopes and microbial signatures. J Hazard Mater 446:130703. https://doi.org/10.1016/j.jhazmat.2022.130703
Kendall C, Elliott EM, Wankel SD (2007) Tracing anthropogenic inputs of nitrogen to ecosystems. Stable Isot Ecol Environ Sci 2:375–449
Kendall C, Young MB, Silva SR, Kraus TEC, Peek S, Guerin M (2015) Tracing nutrient and organic matter sources and biogeochemical processes in the Sacramento River and Northern Delta: proof of concept using stable isotope data. US Geol Surv Data Release. http://dx.doi.org/10.5066/F7QJ7FCM. Accessed May 2023
Komor S (1997) Boron contents and isotopic compositions of hog manure, selected fertilizers, and water in Minnesota (no. 0047–2425). J Environ Qual. https://doi.org/10.2134/jeq1997.00472425002600050004x. Accessed May 2023
Korom SF (1992) Natural denitrification in the saturated zone: a review. Water Resour Res 28:1657–1668. https://doi.org/10.1029/92WR00252
Kruk M, Mayer B, Nightingale M, Laceby J (2020) Tracing nitrate sources with a combined isotope approach (δ15NNO3, δ18ONO3 and δ11B) in a large mixed-use watershed in southern Alberta, Canada. Sci Total Environ 703:135043
Li C, Li S-L, Yue F-J, Liu J, Zhong J, Yan Z-F, Zhang R-C, Wang Z-J, Xu S (2019) Identification of sources and transformations of nitrate in the Xijiang River using nitrate isotopes and Bayesian model. Sci Total Environ 646:801–810. https://doi.org/10.1016/j.scitotenv.2018.07.345
Liu H, Yang J, Ye M, James SC, Tang Z, Dong J, Xing T (2021) Using t-distributed Stochastic Neighbor Embedding (t-SNE) for cluster analysis and spatial zone delineation of groundwater geochemistry data. J Hydrol 597:126146. https://doi.org/10.1016/j.jhydrol.2021.126146
Mariotti A, Landreau A, Simon B (1988) 15N isotope biogeochemistry and natural denitrification process in groundwater: application to the chalk aquifer of northern France. Geochim Cosmochim Acta 52:1869–1878. https://doi.org/10.1016/0016-7037(88)90010-5
Martinelli G, Dadomo A, De Luca DA, Mazzola M, Lasagna M, Pennisi M, Pilla G, Sacchi E, Saccon P (2018) Nitrate sources, accumulation and reduction in groundwater from northern Italy: insights provided by a nitrate and boron isotopic database. Appl Geochem 91:23–35. https://doi.org/10.1016/j.apgeochem.2018.01.011
Meghdadi A, Javar N (2018) Quantification of spatial and seasonal variations in the proportional contribution of nitrate sources using a multi-isotope approach and Bayesian isotope mixing model. Environ Pollut 235:207–222. https://doi.org/10.1016/j.envpol.2017.12.078
Mengeot A, Roland S, Rorive A (2017a) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Mons - Givry, 45 7/8, Notice explicative, SPW, Wallonia, Belgium
Mengeot A, Roland S, Rorive A (2017b) Carte hydrogéologique de Wallonie [Hydrogeological map of Wallonia]. Planchettes Mons – Givry no. 45/7-8, SPW, Wallonia, Belgium
Mengis M, Schif S, Harris M, English M, Aravena R, Elgood R, Maclean A (2005) Multiple geochemical and isotopic approaches for assessing ground water NO3− elimination in a riparian zone. Ground Water 37:448–457. https://doi.org/10.1111/j.1745-6584.1999.tb01124.x
Mitchell RJ, Babcock RS, Gelinas S, Nanus L, Stasney DE (2003) Nitrate distributions and source identification in the Abbotsford–Sumas aquifer, northwestern Washington State. J Environ Qual 32:789–800
Mohamed MA, Terao H, Suzuki R, Babiker IS, Ohta K, Kaori K, Kato K (2003) Natural denitrification in the Kakamigahara groundwater basin, Gifu prefecture, central Japan. Sci Total Environ 307:191–201
Navette E, Bietlot E, Collart C (2014) Réseau de contrôle des C.E.T. en région Wallone C.E.T. de Cronfestu Quatrième campagne de contrôle [Monitoring network for landfills in the Walloon region]. No. 1370/2014. SPW, Wallonia, Belgium
Navette E, Bietlot E, Collart C (2017) Evaluation de la situation environnementale des eaux souterraines 2017 C.E.T. de classe 3 “La Morette” à Flénu [Assessment of the environmental situation of the groundwater 2017 class 3 landfill “La Morette”]. No. 1851/2017, ISSEP, Liège, Belgium
Nikolenko O, Jurado A, Borges AV, Knӧller K, Brouyѐre S (2018) Isotopic composition of nitrogen species in groundwater under agricultural areas: a review. Sci Total Environ 621:1415–1432. https://doi.org/10.1016/j.scitotenv.2017.10.086
Obeidat M, Awawdeh M, Al-Kharabsheh N, Al-Ajlouni A (2021) Source identification of nitrate in the upper aquifer system of the Wadi Shueib catchment area in Jordan based on stable isotope composition. J Arid Land 13:350–374
Ogrinc N, Tamše S, Zavadlav S, Vrzel J, Jin L (2019) Evaluation of geochemical processes and nitrate pollution sources at the Ljubljansko polje aquifer (Slovenia): a stable isotope perspective. Sci Total Environ 646:1588–1600. https://doi.org/10.1016/j.scitotenv.2018.07.245
Orban P, Brouyère S, Batlle-Aguilar J, Couturier J, Goderniaux P, Leroy M, Maloszewski P, Dassargues A (2010) Regional transport modelling for nitrate trend assessment and forecasting in a chalk aquifer. J Contam Hydrol 118:79–93
Oren O, Yechieli Y, Böhlke J, Dody A (2004) Contamination of groundwater under cultivated fields in an arid environment, central Arava Valley, Israel. J Hydrol 290:312–328
Palmucci W, Rusi S (2014) Boron-rich groundwater in central eastern Italy: a hydrogeochemical and statistical approach to define origin and distribution. Environ Earth Sci 72:5139–5157. https://doi.org/10.1007/s12665-014-3384-5
Parks JL, Edwards M (2005) Boron in the environment. Crit Rev Environ Sci Technol 35:81–114
Pedregosa F, Varoquaux G, Gramfort A, Michel V, Thirion B, Grisel O, Blondel M, Prettenhofer P, Weiss R, Dubourg V, Vanderplas J, Passos A, Cournapeau D, Brucher M, Perrot M, Duchesnay E (2011) Scikit-learn: machine learning in Python. J Mach Learn Res 12:2825–2830
Peeters L (2013) A background color scheme for piper plots to spatially visualize hydrochemical patterns. Ground Water 52. https://doi.org/10.1111/gwat.12118
Pirson S, Spagna P, Baele J-M, Damblon F, Gerrienne P, Vanbrabant Y, Yans J (2008) An overview of the geology of Belgium. Presented at the Memoirs of the Geological Survey of Belgium, Geological Survey of Belgium, Brussels, pp 5–26
Pittalis D, Carrey R, Da Pelo S, Carletti A, Biddau R, Cidu R, Celico F, Soler A, Ghiglieri G (2018) Hydrogeological and multi-isotopic approach to define nitrate pollution and denitrification processes in a coastal aquifer (Sardinia, Italy). Hydrogeol J 26:2021–2040. https://doi.org/10.1007/s10040-018-1720-7
Postma D, Boesen C, Kristiansen H, Larsen F (1991) Nitrate reduction in an unconfined sandy aquifer: water chemistry, reduction processes, and geochemical modeling. Water Resour Res 27:2027–2045. https://doi.org/10.1029/91WR00989
Rencher AC (2002) Methods of multivariate analysis, 2nd edn. Wiley, New York
Rezaei M, Nikbakht M, Shakeri A (2017) Geochemistry and sources of fluoride and nitrate contamination of groundwater in Lar area, south Iran. Environ Sci Pollut Res 24:15471–15487. https://doi.org/10.1007/s11356-017-9108-0
Rivett MO, Buss SR, Morgan P, Smith JWN, Bemment CD (2008) Nitrate attenuation in groundwater: a review of biogeochemical controlling processes. Water Res 42:4215–4232. https://doi.org/10.1016/j.watres.2008.07.020
Ronen D, Magaritz M (1985) High concentration of solutes at the upper part of the saturated zone (water table) of a deep aquifer under sewage-irrigated land. J Hydrol 80:311–323
Rorive A, Goderniaux P (2014) L’aquifère du Crétacé de la vallée de la Haine [The Haine Valley Cretaceous aquifer]. In: Dassargues A, Walraevens K (eds) Watervoerende Lagen En Grondwater in België/Aquiferes et Eaux Souterraines En Belgique [Aquifers and groundwater in Belgium]. Academia Press, Gent, Belgium
Sandor J, Kiss I, Farkas O, Ember I (2001) Association between gastric cancer mortality and nitrate content of drinking water: ecological study on small area inequalities. Eur J Epidemiol 17:443–447
Seiler R (2005) Combined use of 15N and 18O of nitrate and 11B to evaluate nitrate contamination in groundwater. Appl Geochem 20:1626–1636. https://doi.org/10.1016/j.apgeochem.2005.04.007
Seitzinger S, Harrison JA, Böhlke JK, Bouwman AF, Lowrance R, Peterson B, Tobias C, Van Drecht G (2006) Denitrification across landscapes and waterscapes: a synthesis. Ecol Appl 16:2064–2090. https://doi.org/10.1890/1051-0761(2006)016[2064:DALAWA]2.0.CO;2
Spalding RF, Exner ME (1993) Occurrence of nitrate in groundwater: a review. J Environ Qual 22:392–402. https://doi.org/10.2134/jeq1993.00472425002200030002x
SPAQUE (2018) Ht0806-009 – “Crayère des Fonds de Morvau” à Binche Surveillance environnementale: Bilan 2018 [Environmental monitoring]. SPAQUE, Liège, Belgium
SPW (2018) Terrils (version 2018) [Mining spoil heaps]. Série, SPW, Wallonia, Belgium
SPW (2022) Banque de Données de l’État des Sols (BDES) - Inventaire par parcelle des informations en lien avec l’état des sols [Soil condition database: inventory by plot of information related to the state of the soil]. SPW, Wallonia, Belgium
SPW, DEE (Direction des Eaux souteraines) (2022a) Etat des nappes et des masses d’eau souterraine de Wallonie [State of the water tables and groundwater bodies in Wallonia]. SPW, Wallonia, Belgium
Su C, Zhang F, Cui X, Cheng Z, Zheng Z (2020) Source characterization of nitrate in groundwater using hydrogeochemical and multivariate statistical analysis in the Muling-Xingkai Plain, Northeast China. Environ Monit Assess 192. https://doi.org/10.1007/s10661-020-08347-6
Sutton MA, Howard CM, Erisman JW, Billen G, Bleeker A, Grennfelt P, Van Grinsven H, Grizzetti B (2011) The European nitrogen assessment: sources, effects and policy perspectives. Cambridge University Press, Cambridge, UK
Thiernesse L (1967) Problèmes de reconversion et d’aménagement de la région boraine [Problems of conversion and development of the Boraine region]. Hommes Terres Nord 1:10–25
Thorburn PJ, Biggs JS, Weier KL, Keating BA (2003) Nitrate in groundwaters of intensive agricultural areas in coastal Northeastern Australia. Agric Ecosyst Environ 94:49–58
Thorndike RL (1953) Who belongs in the family? Psychometrika 18:267–276. https://doi.org/10.1007/BF02289263
Torres-Martínez JA, Mora A, Knappett PSK, Ornelas-Soto N, Mahlknecht J (2020) Tracking nitrate and sulfate sources in groundwater of an urbanized valley using a multi-tracer approach combined with a Bayesian isotope mixing model. Water Res 182. https://doi.org/10.1016/j.watres.2020.115962
Torres-Martínez JA, Mora A, Mahlknecht J, Kaown D, Barceló D (2021) Determining nitrate and sulfate pollution sources and transformations in a coastal aquifer impacted by seawater intrusion: a multi-isotopic approach combined with self-organizing maps and a Bayesian mixing model. J Hazard Mater 417. https://doi.org/10.1016/j.jhazmat.2021.126103
van der Maaten LJP (2022) t-SNE. https://lvdmaaten.github.io/tsne/. Accessed May 2023
van der Maaten LJP, Hinton GE (2008) Visualizing high-dimensional data using t-SNE. J Mach Learn Res 9:2579–2605
Vengosh A, Barth S, Heumann KG, Eisenhut S (1999) Boron isotopic composition of freshwater lakes from Central Europe and possible contamination sources. Acta Hydrochim Hydrobiol 27:416–421
Vitousek PM, Aber JD, Howarth RW, Likens GE, Matson PA, Schindler DW, Schlesinger WH, Tilman DG (1997) Technical report: human alteration of the global nitrogen cycle—sources and consequences. Ecol Appl 7:737–750. https://doi.org/10.2307/2269431
Vystavna Y, Diadin D, Valeriy Y, Hejzlar J, Vadillo I, Huneau F, Lehmann M (2017) Nitrate contamination in a shallow urban aquifer in East Ukraine: evidence from hydrochemical, stable nitrate isotope, and land use analysis. Environ Earth Sci 76. https://doi.org/10.1007/s12665-017-6796-1
Wakida FT, Lerner DN (2005) Non-agricultural sources of groundwater nitrate: a review and case study. Water Res 39:3–16. https://doi.org/10.1016/j.watres.2004.07.026
Wells NS, Hakoun V, Brouyère S, Knöller K (2016) Multi-species measurements of nitrogen isotopic composition reveal the spatial constraints and biological drivers of ammonium attenuation across a highly contaminated groundwater system. Water Res 98:363–375. https://doi.org/10.1016/j.watres.2016.04.025
WHO (2017) Guidelines for drinking-water quality: fourth edition incorporating the first addendum. World Health Organization, Geneva
Widory D, Kloppmann W, Chéry L, Bonnin J, Rochdi H, Guinamant J-L (2004) Nitrate in groundwater: an isotopic multi-tracer approach. J Contam Hydrol 72:165–188. https://doi.org/10.1016/j.jconhyd.2003.10.010
Widory D, Petelet-Giraud E, Brenot A, Bronders J, Tirez K, Boeckx P (2013) Improving the management of nitrate pollution in water by the use of isotope monitoring: the δ15N, δ18O and δ11B triptych. Isotopes Environ Health Stud 49:29–47
Widory D, Petelet-Giraud E, Négrel P, Ladouche B (2005) Tracking the sources of nitrate in groundwater using coupled nitrogen and boron isotopes: a synthesis. Environ Sci Technol 39:539–548. https://doi.org/10.1021/es0493897
Xu S, Kang P, Sun Y (2016) A stable isotope approach and its application for identifying nitrate source and transformation process in water. Environ Sci Pollut Res 23:1133–1148
Xue D, Botte J, De Baets B, Accoe F, Nestler A, Taylor P, Van Cleemput O, Berglund M, Boeckx P (2009) Present limitations and future prospects of stable isotope methods for nitrate source identification in surface- and groundwater. Water Res 43:1159–1170
Acknowledgements
We thank the water production companies IDEA, SWDE, Vivaqua and Farys for sharing some data and making some facilities available in the framework of this project.
Funding
This research was financially supported by SPGE (Société Publique de Gestion de l’Eau – Public Water Management Company), which is a public limited company set up by the Walloon Region. Some of the data collected are linked to the CASPER project, which is also funded by the SPGE (Brouyère et al. 2022).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Christiaens, L., Orban, P., Brouyère, S. et al. Tracking the sources and fate of nitrate pollution by combining hydrochemical and isotopic data with a statistical approach. Hydrogeol J 31, 1271–1289 (2023). https://doi.org/10.1007/s10040-023-02646-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10040-023-02646-1