Isotope techniques for studying nitrate dynamics at Goldschmidt 2019

We are happy to announce that at the recent Goldschmidt 2019 conference in Barcelona our researcher Izabela Bujak (ESR3) gave a talk entitled „Integrated isotope techniques to investigate nitrate dynamics along a land-use gradient in a mesoscale river catchment.”

Izabela Bujak (ESR3) presentation

Goldschmidt is the foremost annual, international conference on geochemistry and related subjects, organized by the European Association of Geochemistry and the Geochemical Society. As we all love data, here are some numbers for Goldschmidt2019 conference:

  • 4,075 delegates who travelled from 74 different countries
  • 14 themes and 121 sessions
  • 4,032 abstracts
  • 2,395 talks including 479 flash talks
  • 2,208 posters
  • 17 pre-conference workshops attended by 444 participants, including Izabela!

Because Izabela is fascinated by the great range of possibilities which isotope techniques offer to trace water and contaminant flow paths, she chose to participate in the workshops dedicated to the application of environmental isotopes and CSIA in contaminated groundwater studies. The course aimed to present the latest advancement in the applications of compound-specific isotopes analysis (CSIA) as well as environmental isotopes in characterizing and assessing contaminated sites. The course covered the application of environmental isotopes, 13C, 2H, 18O, 15N, 34S, 87Sr/86Sr, 37Cl, 81Br, 11B and Tritium, to trace the origin of contaminants and the attenuation processes that take place in the aquifer. Many case studies were presented during the workshop. The topics comprise groundwater pollution from agricultural sources (nitrate), industrial activities (e.g., LNAPLs, DNAPLs) as well as urban activities. Furthermore, the course was designed to present the latest advancement in 13C-CSIA, 37Cl-CSIA, 81Br-CSIA, and 2H-CSIA. Isotopes have been successfully used in determining the source of contaminations, understanding the fate of contaminants in the groundwater, and evaluating the effectiveness of remediation actions including the performance assessment for a broad range of biological (natural and enhanced), chemical (e.g., in situ chemical oxidation [ISCO] and permeable reactive barriers [PRB] and physical (e.g., thermal treatment and pump and treat) remediation strategies.

WP 5: Sustainability of agricultural management strategies at the catchment-scale

Agricultural production in Europe has significantly increased food security but has simultaneously damaged soil and water resources as well as ecosystem biodiversity, and has contributed to climate change (EEA, 2015). This is in part due to elevated inputs of nitrogen (N) and phosphorus (P) to the soil (Pretty, 2008; Tonitto et al., 2006), the migration of pesticides from agricultural fields into surface waters (EU, 2013; Reemtsma et al., 2013), and increased mechanization. Furthermore, declining soil organic carbon (SOC) and increasing soil compaction are recognized as major soil threats in Europe (European Commission, 2012; Van-Camp et al., 2004), and understanding carbon dynamics in agricultural soils is important for mitigating carbon losses (Dawson and Smith, 2007).

Sustainable intensification of agriculture is needed to increase crop production while also managing natural resources sustainably and minimizing environmental impacts. This requires the integration of technologies, practices and natural processes to manage pests, nutrients, and soil and water quality. WP5 focuses on the development of decision support tools to analyze agricultural management impacts related to (1) pesticide use, (2) soil fertility (focusing on soil organic carbon as well as the nutrients N and P), (3) soil compaction, (4) water quality (focusing on N, P and pesticides), and (5) trade offs with crop production. Two separate PhD projects collaborate on these aspects with the idea of creating integrated or complimentary decision support systems (DSSs).

 ESR 14 Madaline Young, Wageningen University (NL): Developing a decision support framework to evaluate the impacts of agricultural management on crop yield, soil quality, and environment

Numerous management strategies already exist to improve nutrient use efficiency, profitability, and environmental impact. However, there is a gap in knowledge on the combined impacts of these management approaches on crop yields, soil quality and environment as well as on optimal combinations of practices given those impacts. DSS science has existed for decades (Power, 2007) and can be used to assess the integrative impacts of agricultural measures, with multi-criteria decision-making being an important development for evaluating agricultural land (Parsons, 2002). Addressing the complexity of management interactions on soil systems and available win-wins and trade-offs, as well as focusing on the dependency of management impacts on local agro-ecosystem properties will ultimately boost long-term agricultural sustainability (Lin, 2011). A user-friendly decision support tool integrating both environmental and agronomic issues within a spatially explicit framework can guide farmers, local and regional policymakers, and fertilizer industry and advisory companies in developing high-impact management strategies.

Madaline will develop a decision-making framework to evaluate the impacts of nutrient, soil and crop management measures on both agricultural production and environmental impacts to maximize crop yields and minimize environmental impacts. Impacts will focus on the soil balance of C, N, and P and on soil compaction, while integrating spatial and temporal scales. A set of sustainability indicators will be used, linked to nutrient, soil, and crop management practices and informative on yields as well as soil organic carbon, nutrient use efficiency and compaction. Using a combination of meta-analysis and process-based modelling, she will quantify the various effects of management practices on the impacts in question, using the indicators as a metric. The second stage of the project will involve creating a DSS tool for evaluating management practices in terms of soil functionality, nutrient budgets, and related environmental impacts. Multi-criteria analysis will be used to assess multiple goals, trade-offs, and management-impact relationships, based on the distance of sustainability indices to target or critical values. The final step is validating the DSS on long-term experimental data and testing its use for farmer stakeholders as well as for providing management recommendations for typical farms in north-western Europe.

ESR 15 Gisela Quaglia, Flemish Institute for Technological Research (BE): Developing a framework to establish cost-effective measures to reduce pesticide impacts on a catchment-scale

ESR 15 Gisela Quaglia, Flemish Institute for Technological Research (BE): Developing a framework to establish cost-effective measures to reduce pesticide impacts on a catchment-scale

The use of pesticides during agricultural production negatively influences water quality and is a major threat to aquatic ecosystems (Bereswill et al., 2014; EU, 2013). Without treatment or targeted mitigation, pesticide pollution is diffused into the environment (Gregoire et al., 2009). Therefore, there is an increased interest in the implementation of agricultural mitigation measures to reduce the environmental impact of pesticides and to reach desired water quality levels (European Commission, 2009, 2000).

There is no perfect unique solution to deal with pesticide input to water bodies (Reichenberger et al., 2007). Consequently, a holistic catchment-scale approach is required for implementing measures (Babut et al., 2013; Brack et al., 2009). Integrated evaluation is needed at the catchment scale, focusing on the combined effects of several mitigation strategies rather than an isolated measure as well as quantifying the effectiveness in reducing pesticides losses towards surfaces water. This has scarcely been attempted altogether. Field experiments under realistic and representative conditions need to be conducted to validate the models and measure the effectiveness of the applied measures.

Gisela focuses on developing targeted pesticide mitigation strategies, monitoring their impact on water quality, and developing an assessment framework to select cost-effective measures to reach a pesticide reduction goal, all at the catchment scale. This study will lead to a practical tool to monitor the pesticide management implementation process and will support good practice in linking science to the farm sector and increasing farmer awareness. Furthermore, other win-win strategies or co-benefits that can be established for topics such as erosion control and nutrient abatement will be taken into account in this study.

Catchment spatial setting for mitigation measures for pesticides. 1) Biofilter to reduce point losses 2) riparian grass strips 3) strategic grassland areas 4) Grass buffer strips in field borders 5) retention basin


Babut, M., Arts, G.H., Barra Caracciolo, A., Carluer, N., Domange, N., Friberg, N., Gouy, V., Grung, M., Lagadic, L., Martin-Laurent, F., Mazzella, N., Pesce, S., Real, B., Reichenberger, S., Roex, E.W.M., Romijn, K., Röttele, M., Stenrød, M., Tournebize, J., Vernier, F., Vindimian, E., 2013. Pesticide risk assessment and management in a globally changing world-report from a European interdisciplinary workshop. Environ. Sci. Pollut. Res. 20, 8298–8312. doi:10.1007/s11356-013-2004-3

Bereswill, R., Streloke, M., Schulz, R., 2014. Risk mitigation measures for diffuse pesticide entry into aquatic ecosystems: Proposal of a guide to identify appropriate measures on a catchment scale. Integr. Environ. Assess. Manag. 10, 286–298. doi:10.1002/ieam.1517

Brack, W., Apitz, S.E., Borchardt, D., Brils, J., Cardoso, A.C., Foekema, E.M., van Gils, J., Jansen, S., Harris, B., Hein, M., Heise, S., Hellsten, S., de Maagd, P.G.-J., Müller, D., Panov, V.E., Posthuma, L., Quevauviller, P., Verdonschot, P.F., von der Ohe, P.C., 2009. Toward a Holistic and Risk-Based Management of European River Basins. Integr. Environ. Assess. Manag. 5, 5. doi:10.1897/IEAM_2008-024.1

Dawson, J.J.C., Smith, P., 2007. Carbon losses from soil and its consequences for land-use management. Sci. Total Environ. 382, 165–190. doi:10.1016/j.scitotenv.2007.03.023

EEA, 2015. State and Outlook 2015 the European Environment. European Environment Agency, Copenhagen. doi:10.2800/944899

EU, 2013. Rural development in the European Union – Statistical and economic information – Report 2013.

European Commission, 2012. JRC Reference Reports: The State of Soil in Europe. Publications Office of the European Union, Luxembourg. doi:10.2788/77361

European Commission, 2009. Directive 2009/128/EC of the European Parliament and of the Council of 21 October 2009 establishing a framework for Community action to achieve the sustainable use of pesticides. Off. J. Eur. Union. doi:10.3000/17252555.L_2009.309

European Commission, 2000. Directive 2000/60/EC Framework for Community action in the field of water policy.

Gregoire, C., Elsaesser, D., Huguenot, D., Lange, J., Lebeau, T., Merli, A., Mose, R., Passeport, E., Payraudeau, S., Schütz, T., Schulz, R., Tapia-Padilla, G., Tournebize, J., Trevisan, M., Wanko, A., 2009. Mitigation of agricultural nonpoint-source pesticide pollution in artificial wetland ecosystems. Environ. Chem. Lett. 7, 205–231. doi:10.1007/s10311-008-0167-9

Lin, B.B., 2011. Resilience in Agriculture through Crop Diversification: Adaptive Management for Environmental Change. Bioscience 61, 183–193. doi:10.1525/bio.2011.61.3.4

Parsons, J., 2002. Agland Decision Tool : A Multicriteria Decision Support System for Agricultural Property 181–186.

Power, D.J., 2007. A Brief History of Decision Support Systems. DSSResources.COM.

Pretty, J., 2008. Agricultural sustainability: concepts, principles and evidence. Philos. Trans. R. Soc. B Biol. Sci. 363, 447–465. doi:10.1098/rstb.2007.2163

Reemtsma, T., Alder, L., Banasiak, U., 2013. Emerging pesticide metabolites in groundwater and surface water as determined by the application of a multimethod for 150 pesticide metabolites. Water Res. 47, 5535–5545. doi:10.1016/j.watres.2013.06.031

Reichenberger, S., Bach, M., Skitschak, A., Frede, H.G., 2007. Mitigation strategies to reduce pesticide inputs into ground- and surface water and their effectiveness; A review. Sci. Total Environ. 384, 1–35. doi:10.1016/j.scitotenv.2007.04.046

Tonitto, C., David, M.B., Drinkwater, L.E., 2006. Replacing bare fallows with cover crops in fertilizer-intensive cropping systems: A meta-analysis of crop yield and N dynamics. Agric. Ecosyst. Environ. 112, 58–72. doi:10.1016/j.agee.2005.07.003

Van-Camp, L., Bujarrabal, B., Gentile, A.R., Jones, R.J.A., Montanarella, L., Olazabal, C., Selvaradjou, S., 2004. Reports of the Technical Working Groups Established Under the Thematic Strategy for Soil Protection. Office for Official Publications of the European Communities, Luxembourg.

The faces of INSPIRATION

The project is reaching the end. INSPIRATION ITN final conference took place within the framework of the Groundwater Quality Conference 2019 (GQ 2019) at the University of Liège (Belgium) on 9-12 September 2019.

This conference was an excellent opportunity for us, the INSPIRATION early-stage researchers (ESRs) to feature oral and posters presentations, cochairing conference sessions, and disseminating the research we have done in the past three years. Our expo corner exhibited our project work supported by the recently published technical bulletins, a poster that displayed the faces of INSPIRATION, and a video that summarised the work of each of the ESRs. Throughout the four days of the conference, we discussed our research and the project with many participants. Over 20 persons gave us their emails asking for more information.

Inspiration corner

This final event gave us the chance to look back and see how many things we accomplished since our first meeting in March 2017. The journey is not over yet, we still need to obtain our PhD degree, but much has been done, and we could prove during this conference.

Our oral presentations:

        • Izabela Bujak – Inspiration Talk: Integrative Isotope Techniques To Evaluate The Fate and Transport of Nitrogen In An Alpine Foothill Catchment (ESR3)
        • Alexandra Giber – Inspiration Talk: Quantification of Nitrate Reduction Potential and Kinetics of Soil Samples Obtained From Sandy Aquifers (ESR7)
        • Olha Nikolenko – Inspiration Talk: Effects of The Hydrogeochemical Stratification On The Distribution of Ghgs Concentrations and Their Production/consumption Processes In Groundwater (ESR6)
        • Robin Weatherl – Inspiration Talk: Identifying Sources and Processes Impacting Groundwater Recharge In The Human Environment (ESR4)


ESR Olha Nikolenko



ESR Izabela Bujak
ESR Alexandra Giber

Also supervisors presented:

        • Mario Schirmer – Invited Talk : Impact of Urbanization On Groundwater Recharge: Case Study Dübendorf, Switzerland (EAWAG)
        • Steve Thornton – Inspiration Talk : Introduction to INSPIRATION Marie Skłodowska-Curie Innovative Training Network (University of Sheffield)

We presented some interested posters:

        • Domiziana Cristini – Isotopic Constraints On The Fate of Phosphate In Agricultural Catchments
        • Gisela Quaglia – A Framework For Targeting Mitigation Measures To Reduce Pesticide Impacts On Water (ESR15)
        • Maximilian Ramgraber – Pseudo-Online Optimization of High-Conductivity Structures From Multiple-Point Statistics (ESR5)
        • Bastian Saputra – Developing Biosensors To Measure The Bioavailability of Heavy Metals In The Remediation of Contaminated Soil (ESR9)
        • Rosa I Soria – Immobilization of Cd, Pb and Zn In Soil Solution and Contaminated Soil Using Biochar To Improve Soil Quality (ESR8)
        • Madaline Young – Development of A Decision Support Framework To Evaluate The Impacts of Agricultural Management On Crop, Soil, and Environmental Quality (ESR14)

        About the conference:

        The Groundwater Quality Conference 2019 (GQ 2019) was held at the University of Liège (Belgium) on 9-12 September 2019.

        The conference theme, groundwater quality in the transition between rural and urban environments, focused on the need to protect, manage, repair and sustain groundwater quality in growing rural and urbanised environments.

        The event registered over 270 participants and 277 posters/oral presentations from academic, industry, regulatory, contractor, consultant, planners.

        Soon, presentations, posters and pictures can be found online here:

Innovative technologies for measuring fluxes of agricultural chemicals in the subsurface

In the last five decades, there has been a huge population growth which reflected  in an exponential demand in food consumption. The demand for higher productivity rates was satisfied by an extensive use of phosphorus and nitrogen fertilisers, which subsequently led to an extensive contamination of the aquifers. The impact of agricultural sources carrying excess phosphorus and nitrogen that ends up in the surface water still remains obscure even after implementation of strict regulations codifying fertilizer inputs to control the “surface” runoff. Therefore, focus is now slowly drifting towards exploration of the “sub-surface” pathways. Apart from run-off, excessive fertilizer input can also result in soil leaching causing percolation of phosphorus and nitrogen from soil into groundwater.

Currently, optimization of resource usage and its sustainable management is of utmost importance. Hence, monitoring of water quality is very important,since it can provide information on the status of the aquifers and prevent or address more effectively possible contamination phenomena. The subsurface of our Earth acts as a sink for all the materials used on its surface during human and natural activities, including the fertilizers and pesticides consumed for agricultural purposes. There is evidence showing that the groundwater is highly susceptible to pollutants. Contamination at the subsurface level is much more challenging than surface level due to its difficult to getting detected, the slow movement and its physical constraints.

However, technological advancements in the environmental sector have recently enabled monitoring of nutrient contamination using various old and new sampling techniques. Work Package 1 focuses on groundwater monitoring using both passive sampling and continuous sampling techniques by introducing two different research projects dealing with phosphorus and nitrogen contamination in the subsurface.

ESR 2 Priyanka Banerjee: Quantifying the phosphorus flux leaching from field to groundwater and surface water using innovative techniques

In past, phosphorus was envisaged to be “immobile” in groundwater, but with time, the soil-groundwater-surface water linkage has started getting more evident. Only recently P leaching started being recognized as a dominant P loss pathway (Heathwaite et al., 2005; van der Salm et al., 2011), but this field needs more scientific attention and development. Studies mostly have focused on P mobility and behaviour in soil and surface water, but not on the P transport via leaching from soil via groundwater to surface water. This is because groundwater lacks proper characterization of its solute contaminants (like nitrogen, P, Volatile Organic Contaminants). This knowledge gap can be attributed to three main factors: (1) “hidden” quotient of groundwater that makes monitoring its contamination still a big challenge, (2) complex chemistry of phosphorus at soil-water interface, (3) methods used for flux calculations. Hence, proper characterisation and quantification of P fluxes in groundwater is essential to assess its leaching losses via the groundwater pathway.

Erroneous estimation of phosphorus in groundwater arises from simulations based on phosphorus concentration measurements and estimated Darcy water-flux values. Consequently, this research will focus on application of direct flux measurements. The measurement and interpretation of mass fluxes in favour of concentrations is gaining more and more interest, especially within the framework of characterization and management of groundwater contamination (Annable et al., 2005; Basu et al., 2006; Verreydt et al., 2010). Conventional methods of estimating contaminant fluxes involve individual measurements of the contaminant concentrations and calculations of the Darcy water fluxes (Michel, 2013; Verreydt et al., 2010).

Verreydt (2012) points out the three main problems with existing contaminant flux calculations. (1) First, groundwater is sampled from the monitoring wells and then analysed in the lab in terms of concentration of contaminants. Hence, these measurements still needs to be combined with groundwater water flux estimations (back calculated) in order to finally calculate the contaminant mass flux and mass discharge. This makes contaminant flux calculations with this method very highly uncertain. (2) Secondly, a huge problem is that the concentration measurements don’t take into account the variations in groundwater flow and contaminant concentrations as they are “snapshot” measurements. (3) Soil heterogeneities exist which is why the correlation between concentration measurements and water flux is very difficult to make. All of this explains the existence of huge uncertainties in flux calculations used for current groundwater remediation measures resulting in failures.

Figure 1: Passive flux samplers to monitor phosphorus fluxes in groundwater

In this PhD study, ESR1 attempts to set up a methodological framework to predict the impact and efficiency of innovative passive sampling techniques and to evaluate the efficiency of each of them against other passive samplers in different field conditions (low P, high P, high iron, low iron).

ESR 2, Polyxeni Damala, Geolys SPRL: Development of a sensor for monitoring nitrate in groundwater

Nitrate is a ubiquitous pollutant of surface water and groundwater. It originates from several sources, which might be either the result of human intervention or not. Among them, agriculture plays a major role in nitrate contamination, owing to the extensive use of fertilizers which are applied for the increase of crop productivity. When the nutrients originating from the nitrogen fertilizers are not taken up by the plants, they end up in the groundwater, enriching the subsurface with considerable amounts of nitrate.

Increased levels of nitrate lead to the nutrient enrichment of water bodies and the potential spreading of algal blooms. An important concern related to the algal growth is the depletion of the oxygen levels in the water bodies. This depletion is attributed to the activity of bacteria, which use the oxygen in order to decompose the algae when they die. The resulting oxygen deficiency affects the rest of the living organisms, which consequently die (Addiscott, 2005).

Following the nitrate levels in the subsurface is essential for preserving our water resources. The main objective of this research project is to develop a method for the continuous and in-situ monitoring of nitrate in water, overcoming the limitations of the current sensors that prevent their use in specific applications. The idea behind this project lies on the use of specific compounds which are able to reversibly trap the nitrate ions found in water. These nitrate-selective compounds will be incorporated into suitable matrices which can then be used either for optical or electrochemical sensing of nitrate. Testing different experimental conditions, types of matrices, sensing mechanisms and other auxiliary compounds that are necessary for the enhancement of the sensor response, are among the different steps that will be implemented. Since the focus is shifted on groundwater nitrate contamination, different ions which are commonly found in the subsurface might interfere on the sensor response. Hence, examining the influence of those ions on the performance of the sensor will be another important aspect of this study.

For this project, both theoretical and experimental (laboratory-based) work is under progress. The output of this research aims not only to overcome the limitations of the existing real-time sensors, but also to demonstrate a new method for monitoring nitrate and other ions of interest found in the water. In addition to this, the measurement of nitrate fluxes will also be feasible through the combination of the nitrate concentration data obtained by the sensor with the groundwater fluxes. For this purpose, a method that can be used to monitor the variations of groundwater fluxes has already been developed and tested by the Hydrogeology and Environmental Geology group of Liège University (Brouyère, 2008).

We invite you to see our video:


Addiscott, T. M. (2005) Nitrate, agriculture and the environment. CABI Publishing. Oxfordshire, UK

Annable, M.D., Hatfield, K., Cho, J., Klammler, H. , Parker, B.L., Cherry, J.A. and Rao, P.S.C. (2005). Field-scale evaluation of the passive flux meter for simultaneous measurement of groundwater and contaminant fluxes. Environmental Science and Technology, 39, 7194–7201

Basu, N.B., Rao, P.S.C., Poyer, I.C., Annable, M.D. and Hatfield. K. (2006). Flux-based assessment at a manufacturing site contaminated with trichloroethylene. Journal of Contaminant Hydrology, 86, 105-127

Brouyère S. (2008) A new tracer technique for monitoring groundwater fluxes: The Finite Volume Point Dilution Method. J. of Cont. Hydrol., 95 (3-4), 121-140

Heathwaite, A. L., Dils, R. M., Liu, S., Carvalho, L., Brazier, R. E., Pope, L., Hughes, M., Phillips, G. and May, L. (2005). A tiered risk-based approach for predicting diffuse and point source phosphorus losses in agricultural areas. Science of the total environment, 344, 225-239

Michel J. (2013). Groundwater quality measurement with passive samplers – Code of best practices. Citychlor project, 65 pages

van der Salm, C., Dupas, R., Grant, R., Heckrath, G., Iversen, B. V., Kronvang, B., Levi, C., Rubaek, G. H. and Schoumans, O. F. (2011). Predicting Phosphorus Losses with the PLEASE Model on a Local Scale in Denmark and the Netherlands. Journal of Environmental Quality, 40, 1617-1626

Verreydt G., Bronders J., Van Keer van I., Diels, D. and Vanderauwera P. (2010). Passive Samplers for Monitoring VOCs in Groundwater and the Prospects Related to Mass Flux Measurements. Ground Water Monitoring and Remediation, 30(2), 114-126

Verreydt G. (2012). New approaches of groundwater management using contaminant mass flux measurement. PhD dissertation, University of Antwerp, 147 pages