Poster session
Posters on site: Thu, 1 May, 14:00–15:45 | Hall A
Pesticide leaching into groundwater poses a significant risk related to water security and public health, particularly in intensively cultivated, overexploited and contaminated regions. Farmers in most developing nations select pesticides based on their pest-killing efficiency and cost to increase crop yield and economic benefits rather than their potential environmental impacts. Therefore, this study estimated the leaching potential of 31 commonly used pesticides in the upstream (US), midstream (MS), and downstream (DS) regions of the Hindon River basin (HRB), India. The leaching indices such as the Groundwater Ubiquity Score, LEACH Index, Modified LEACH Index, Hornsby Index, LIX Index, LIN Index, and Global Leachability Index were employed. Key pesticide properties, such as water solubility, carbon-water partition coefficient, half-life, vapor pressure, and Henry's law constant, were used to calculate all the indices. In addition, pesticide consumption patterns and hydrogeological data—such as soil type, rainfall, aquifer hydraulic conductivity, and groundwater levels—were incorporated into the analysis to pinpoint the location and specific pesticides. The results indicate that pesticides like sulfosulfuron, metsulfuron methyl, imidacloprid, atrazine, carbendazim, dimethoate, and glyphosate are major contributors to groundwater contamination due to their mobility, persistence, and widespread usage. Specifically, the US regions, with shallow groundwater levels (< 8 mbgl) and high annual rainfall (~1100 mm), showed elevated leaching risks from carbendazim and dimethoate pesticides. However, the MS and DS regions, characterized by moderate rainfall (600–800 mm), moderate groundwater levels (> 12 mbgl) and higher aquifer hydraulic conductivity (33 m/day), exhibited significant leaching risks from pesticides like sulfosulfuron, metsulfuron methyl, imidacloprid, and atrazine. Instead of the low leaching potential of pesticides, such as fipronil, chlorpyrifos, and lambda-cyhalothrin, their residues may be detectable in groundwater due to high application rates. This study highlights the complex interplay between pesticide leaching risks based on the HRB consumption pattern and hydrogeological conditions. The results of this study would be helpful for pesticide regulation, the adoption of less persistent compounds, enhanced monitoring programs, safeguarding public health, and identifying potential recharge locations for agriculturally managed aquifer recharge (AgMAR). The findings suggest that future studies should focus on regular field monitoring of pesticide residues, evaluating aquifer vulnerability under varying pesticide consumption and climatic conditions, and incorporating advanced modeling tools to predict long-term contamination risks to ensure groundwater sustainability in the HRB.
How to cite: Jadav, K. and Yadav, B.: A Comprehensive Assessment of the Pesticide Leaching: Insights from the Hindon River Basin, India, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-222, https://doi.org/10.5194/egusphere-egu25-222, 2025.
This study conducted particle flow and chemical precipitation experiments to investigate the effect of physical-chemical combined clogging on the permeability of geotextile envelope. The results show that there is a synergistic effect between physical clogging caused by soil particle accumulation and chemical clogging due to salt precipitation. Chemical precipitation exacerbates physical clogging, while physical clogging promotes the formation of chemical precipitation. The chemical precipitates on the upstream of the geotextile envelope binds the particles to each other and to the fibers of the geotextile envelope, while on the downstream, precipitates tends to encapsulate the fibers, with less physical clogging. After combined clogging, the permeability coefficient of the geotextile envelope decreases rapidly with the increasing of the clogging material, and then decreases slowly. When the area density of the clogging material is less than 91.02 g/m², it shows a linear decrease, and then followed by a logarithmic decrease. Physical-chemical combined clogging is more severe than single physical or chemical clogging. After the permeability stabilizes, for the same clogging mass, the decrease in permeability caused by combined clogging is 1.2 times and 2 times greater than that caused by physical and chemical clogging, respectively.
How to cite: Qin, S., Wu, J., Guo, C., and Yao, C.: Effect of physical-chemical combined clogging on the permeability of geotextile envelopes for subsurface drainage systems in arid regions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1967, https://doi.org/10.5194/egusphere-egu25-1967, 2025.
Groundwater quality assessment is crucial for ensuring safe drinking water and sustainable resource management. However, traditional monitoring methods involving extensive sampling and laboratory analysis are time-consuming and costly. The present study proposes an efficient approach for predicting groundwater quality in Madhya Pradesh, India using data-driven models and an entropy-weighted water quality index (EWQI). A large spatiotemporal dataset of different parameters of groundwater quality like pH, total dissolved solids (TDS), calcium (Ca2⁺), total hardness (TH), nitrate (NO₃⁻), sodium (Na⁺), chloride (Cl⁻), potassium (K⁺), sulfate (SO₄2⁻), magnesium (Mg2⁺), and fluoride (F⁻) from the year (2003-2023) across Madhya Pradesh was analysed. All advanced data-driven models such as Random Forest (RF), eXtreme Gradient Boosting (XGBoost), Artificial Neural Network (ANN), and Support Vector Machine (SVM) were developed to predict the EWQI using easily measurable parameters pH, TH and TDS. The individual ability of the models was assessed using statistical analysis with the coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE). During the training phase, all models such as RF, SVM, XGBoost, and ANN proved excellent predictive capabilities, achieving an R2 value exceeding 0.90 while maintaining minimal errors when pH, TH, and TDS were considered as input variables. The overall outcomes confirmed that the data-driven models could accurately estimate the EWQI, closely matching the actual values with an R2 greater than 0.90. This finding highlights the model's ability to predict a reliable overview of water quality for a small area using easily measurable parameters.
Keywords: Groundwater, Data-driven, Drinking water, Water Quality Index, Machine learning
How to cite: Umare, S., Thawait, A. K., and Dhawane, S. H.: Assessment of Groundwater Quality of Madhya Pradesh, India using Data-Driven Approaches, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-599, https://doi.org/10.5194/egusphere-egu25-599, 2025.
Emerging pollutants (EPs) are contaminants detected in water bodies that lack thorough prior investigation, resulting in limited regulatory frameworks for their control. This poses a significant threat to regions heavily reliant on groundwater for agriculture, drinking water, and other essential uses. The Canary Islands, particularly El Hierro and La Palma, serve as critical case studies due to their unique ecosystems and dependence on groundwater. El Hierro, designated as a UNESCO biosphere reserve in 2000, operates primarily on renewable energy, whereas La Palma exhibits diverse hydrological dynamics influenced by agricultural and urban activities.
A comprehensive analysis of 70 EPs was conducted at 19 sampling points in El Hierro and at 14 locations across La Palma, utilizing high-performance liquid chromatography-mass spectrometry (HPLC-MS). The study focused on five EP categories: ultraviolet (UV) filters, UV blockers/stabilizers, parabens, pharmaceutically active compounds (PhACs), and pesticides. In El Hierro, pesticide residues were absent; however, significant concentrations of UV filters, UV stabilizers, and PhACs were detected, with La Frontera municipality showing the highest contamination. In contrast, La Palma exhibited notable concentrations of PhACs and UV stabilizers, particularly in Breña Baja and wastewater treatment plants (WWTPs). Pesticides, including imidacloprid and acetamiprid, were detected at concerning levels in La Palma's groundwater.
Cluster analysis revealed spatial patterns of EP distribution, segmenting the islands into distinct zones based on pollutant concentrations. In El Hierro, four clusters were identified, with sampling depth correlating positively with EP levels, highlighting potential vertical contamination gradients. Similarly, La Palma showed three to five clusters delineating contamination hotspots, aiding in the identification of priority areas for remediation. These findings underscore the urgent need for preventive measures to mitigate EP entry into the water cycle from domestic, agricultural, and industrial sources, beyond traditional remediation approaches post-contamination.
Comparative analysis between the islands demonstrated shared contamination trends but also emphasized unique local factors influencing EP presence. This highlights the necessity of tailored management strategies to protect groundwater resources in these fragile environments. Future research should focus on elucidating the mechanisms driving high EP concentrations at various depths and assessing long-term impacts on ecosystem and human health.
This study advocates for comprehensive regulatory frameworks and proactive strategies to prevent EP contamination, ensuring the preservation of groundwater resources essential to the sustainability of the Canary Islands.
How to cite: Gasco Cavero, S., Jimenez, J., Baquedano, C., Martínez, J., Sariago, R., Marazuela, M. Á., Santamarta, J. C., and García-Gil, A.: Assessment of Emerging Pollutants in Groundwater Resources of El Hierro and La Palma (Canary Islands): A Comparative Study, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11976, https://doi.org/10.5194/egusphere-egu25-11976, 2025.
Italy is the leading rice producer in Europe, with 92% of its production concentrated in the Piedmont–Lombardy rice basin in Northern Italy. To increase yields, farmers use fertilizers, which can potentially lead to nitrate contamination of groundwater. However, there is limited research in Italy on the extent to which rice production contributes to nitrate pollution. Assessing the environmental impact of rice production is therefore crucial, as water pollution is a major issue for the sustainability of rice-growing regions. This is particularly important as the protection of water from nitrate pollution caused by agricultural activities is a key aspect of European Union legislation, specifically the Nitrates Directive 91/676/EEC.
This study focuses on the Lomellina area, a sub-region of the Piedmont–Lombardy rice basin, located on the left bank of the Po River and along the Ticino River. This area has 90.000 ha of irrigated crops out of a total agricultural area of 125,000 ha, of which 70% is devoted to rice cropping.
Our objectives were to identify the factors controlling nitrate concentrations and to assess groundwater vulnerability based on the relationship between observed concentrations and statistically significant explanatory variables. Nitrate concentrations were measured in 17 groundwater samples collected from shallow monitoring wells in June 2024 across the Lomellina area. The factors initially considered for deriving the associated explanatory variables to be used in the analysis were: topography, groundwater recharge and table depth, presence of irrigation canals, vertical hydraulic conductivity, and land use. Generalized linear regression (GLR) models were used to assess the relationships between nitrate concentrations and twelve explanatory variables.
Covariate selection was done based on Akaike's Information Criterion corrected (AICc) and adjusted R2 values. The best GLR model fit (AICc=140.7 and adjusted R2= 0.73) showed that the most important covariates are: topography, slope, groundwater table depth, vertical hydraulic conductivity, and distance to rice fields. These covariates were statistically significant (at a 0.05 level) except for vertical hydraulic conductivity. Nitrate concentration and slope were negatively correlated, while the other covariates showed positive correlation. Next steps will include investigating and addressing spatial autocorrelation, and build a predictive model and explore the use of machine learning techniques.
An improved understanding of the spatially varying relation between nitrate concentrations and influencing factors could be used to produce reliable groundwater vulnerability maps and help to assess the environmental impact of rice cultivation. Our approach highlights the importance of local variability and contributes to discussion on the regional-scale impacts.
This study was carried out in the context of the PROMEDRICE project (https://promedrice.org/; PRIMA-Section2–2022) funded, for the Italian partners, by MUR (Italian Ministry of University and Research).
How to cite: Baják, P., Bricchi, P., Masetti, M., Pedretti, D., Gilardi, G., Facchi, A., and Sorichetta, A.: Application of generalized linear regression (GLR) models to study spatially varying nitrates concentration in groundwater in a large paddy area of Northern Italy, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15479, https://doi.org/10.5194/egusphere-egu25-15479, 2025.
The rising likelihood of extreme weather events like droughts and floods poses a growing threat to reliable crop production for farmers. Soils may become too dry to support crop growth or too wet and flood, resulting in a partial or total loss of yield. Controlled drainage with subirrigation (CD-SI) offers a potential solution to retain and discharge water in agricultural fields by connecting subsoil drainage pipes to a control pit. This setup allows farmers to manage the water levels independently in the control pit, rather than relying on weir levels which are typically controlled by water authorities. Subirrigation can supply water to the control pit during dry conditions, increasing water pressure in the pipes and causing water to infiltrate the soil, thereby recharging water in the agricultural field. However, as the CD-SI system alters the hydrological functioning of the agricultural water system, it can impact (ground)water nutrient dynamics.
While few studies have examined the effects of CD-SI on nutrient concentrations in agricultural water systems, their findings and interpretations have varied widely. Therefore, this study aims to investigate the impact of a CD-SI system installed in an agricultural field in the Netherlands on nutrient concentrations, compared to a reference field without a drainage system. Continuous field measurements of hydraulic head, soil water potential, and soil moisture content were combined with water quality analyses at nine locations, including five groundwater and two surface water sites. Nutrient concentrations and distributions were compared between the experimental and reference fields over six sampling rounds spanning eight months. Additionally, the input (i.e., groundwater) and output water of the CD-SI system were analysed to assess the nutrient flux through the drainage system.
Our results indicate that following manure application, the experimental field exhibited a greater increase in nutrient concentrations in both shallow and deep groundwater compared to the reference field. During subirrigation, nutrient concentrations in the experimental field followed the trends of the nutrient concentrations of the input water of the system. Surface water nutrient concentrations were not influenced by the CD-SI system’s output. Additionally, there appears to be a spatial relation between the nutrient concentrations and distance to the subirrigation pipes.
These findings provide insights into how CD-SI systems influence nutrient concentrations, and distributions under different operational modes (e.g., subirrigation on/off, free/controlled drainage). The results of this study could help policymakers and farmers determine whether CD-SI systems are a suitable solution for improving the hydrological and nutrient situation in their particular hydrogeological and chemical circumstances.
How to cite: Bonné, J., de Bruin, J., Rakonjac, N., Mustafa, S., de Wit, J., van der Ploeg, M., and Bartholomeus, R.: Effects of Controlled Drainage with Subirrigation on Nutrient Concentrations in an Agricultural Field in the Netherlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16765, https://doi.org/10.5194/egusphere-egu25-16765, 2025.
After their disposal, single-use plastic products end up in environments and start withering, eventually breaking down into Nanoplastics (NPs). This has become an emerging environmental concern. Unsupervised disposal has caused their entry into groundwater and eventually reaches the human body through the food chain, causing health risks. There is a significant research gap in studying realistic NPs that are non-spherical NP particles. A lab produced NPs suspensions prepared for the experiments. The NPs in groundwater act as a vector for other contaminants, such as atrazine, which is widely used as herbicide. The environmental persistence of atrazine can cause soil and water contamination due to its hydrophobic nature and its tendency to adsorb onto particulate matter, including nanoparticles, making it ideal for getting transported by NPs in the groundwater. Hence, it is essential to study its adsorption dynamics and ecological impacts in the presence of NPs derived from single-use plastic products such as polystyrene nanoplastics (PSNP). This study aims to understand the adsorption of atrazine by realistic PSNPs and the environmental risks posed by pesticide and nanoplastic co-contamination. Adsorption studies of PSNPs and atrazine were done varying different parameters like contact time, the concentration of atrazine, and NP, salinity and pH. Adsorption of atrazine was found highest for the highest concentration of NPs. Salinity increased the adsorption of atrazine onto PSMPs. The study helped to conclude that the adsorption of atrazine onto realistic NPs is possible.
How to cite: Kundankadavan, T., Goel, S., and Narayanan, S.: Adsorption Dynamics of Atrazine on realistic Polystyrene Nanoplastics: Insights into Co-Contamination Risks, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18972, https://doi.org/10.5194/egusphere-egu25-18972, 2025.
Posters virtual: Mon, 28 Apr, 14:00–15:45 | vPoster spot A
EGU25-11817 | ECS | Posters virtual | VPS8
Ecohydrogeological characteristics of spring waters in rural areas (northeast of Moscow region)Mon, 28 Apr, 14:00–15:45 (CEST) | vPA.15
Anthropogenic impact on aquifers leads to variations of groundwaters chemical content. This study is determined to describe current geochemical characteristics of springs in Shelkovo district in order to assess the quality of the water that is used for drinking purposes by residents.
The geological structure of the territory includes Devonian, Upper Carboniferous, Upper Jurassic and Lower Cretaceous terrigenous-carbonate rocks, overlapped by thin Quaternary sandy deposits. Surface sediments are permeable to polluted runoff waters, which can increase the vulnerability of groundwater and reduce its quality.
This research presents the obtained results of water parameters (COD, pH, electrical conductivity), the content of major ions (Ca2+, Mg2+, Na+, K+, NH4+, HCO3-, Cl-, SO42-, NO3-) for 12 springs. The spring waters are slightly mineralized (M=0.1-0.5 g/l), pH values vary from 5.5 to 7.5. The total hardness is 0.63-5.7 mg-eq/l. The composition of the water is variable. Springs could be divided by the content of major anions: the dominance of HCO3- which is due to natural causes. In some cases the presence of Cl- and SO42- because of the use of fertilizers and deicing reagents in urban territories.
The concentration of major ions was compared to maximum permissible concentrations in drinking water (by WHO standards). It was noted to slightly exceed the limit for nitrate ion as well as for chemical oxygen demand. Some waters had a pH indicator lower than the standard range.
Comparison of the ratios Cl-/(Cl-+Na+) and Na+/(Na++Cl-) to total dissolved salt was applied in order to figure out the mechanism of spring waters forming (Gibbs, 1970). The results showed that chemical composition is primarily controlled by rock weathering. The ratio relationships between equivalent content Cl-/Na+, HCO3-/Na+, Ca2+/Na+ indicate the type of rocks as a silicate (Gaillardet, 1999). The effect of human impact on groundwaters used to be assessed by comparing the equivalent ratios Cl-/Na+ and NO3-/Na+ (Zhang et al, 2024). The calculations performed summarised anthropogenic impact, including agronomic activities. Significantly connections between various major ions were pointed out due to correlation analysis: as well as fertilizer components and pesticides, anti-icing reagents for roads in winter season and household chemicals from sewers were detected.
The studied waters were formed by dissolving silicate rocks by atmospheric precipitation. As it was figured out by a significant role of chloride and sulfur ions, and presence of nitrogen-ions, the area of springs' feeding is located in permeable contaminated quaternary sediments. But despite anthropogenic impact, the chemical composition of springs correspond to WHO standards for drinking waters.
References
Gaillardet J., Dupre B., Louvat P., Allegre C.J. Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers // Chemical geology – 1999. – Т. 159. – №. 1-4. – С. 3-30.
Gibbs R. J. Mechanisms controlling world water chemistry //Science. – 1970. – Т. 170. – №. 3962. – С. 1088-1090.
Zhang, H., Wang, Z., Wang, X. et al. Hydrochemical characterization and health risk assessment of different types of water bodies in Fenghuang Mountain Area, Northeast China. Environ Geochem Health 46, 292 (2024)
How to cite: Gusarova, D. and Yablonskaya, D.: Ecohydrogeological characteristics of spring waters in rural areas (northeast of Moscow region), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11817, https://doi.org/10.5194/egusphere-egu25-11817, 2025.
EGU25-21834 | ECS | Posters virtual | VPS8
A step towards the protection and management of the Shallow Aquifer of the Keta Basin, in Ghana West Africa: an initial physico-chemical characterisationMon, 28 Apr, 14:00–15:45 (CEST) | vPA.22
The Coastal Unconfined Shallow Sandy Aquifer of the Keta Basin, made up of Quaternary gravel, sand and clay and Neogenic Limonic deposits is the most economically accessible aquifer in Southern Volta, Ghana, West Africa. Water from the aquifer supports domestic supply and vegetable farming, which is the main stay of the area’s economy (Nerquaye-Tetteh 1993; Helstrup et al. 2007; Yidana et al. 2007). Despite the importance of this shallow aquifer, it is vulnerable to contamination from saline intrusion and agricultural activity in the area (Gill 1969; Nerquaye-Tetteh 1993; Kortatsi 1994; Kortatsi et al. 2005; Helstrup 2006). Protecting and managing this aquifer effectively will require the appreciation of the flow regime and dynamics via the collection of hydrogeological information such as geochemical properties and their variation over the years, hydraulic gradient, flow direction, well density, and their abstraction rates. However, this data is non-existent. This work set out to collect these basic hydrogeological information. This work was done via: geochemical sampling and analyses of thirty-five (35) wells for facies discrimination; the hydraulic head mapping of forty-five (45) wells for flow direction mapping and hydraulic gradient distribution, and particle size distribution testing of sampled aquifer material for the hydraulic conductivity distribution. The geochemical datasets showed: neutral and well buffered water groundwater; nitrates occurring in all the samples, with [NO3-] ranging between 0.35 – 25.3 mg/L, indicative of possible human influence on groundwater in the area; four (4) main water types from the analyses as: Na-Cl, Ca-(HCO3)2, Na-HCO3, and Ca-Cl2 with percentage dominances of 47, 41, 9 and 3% respectively. Na-Cl and Na-HCO3 waters characterised by very high SECs and found in farm wells located near the coast and lagoons suggest saline intrusion (due to heavy pumping on farms) from the sea and lagoon. The central part of the area, has fresh water which with the Ca-(HCO3)2 water type, indicative of natural rock weathering processes and flow dynamics. Analysing the irrigation water use parameters from the geochemical showed that the water in the area was suitable with respect to residual sodium carbonate (RSC) and magnesium absorption ratio (MAR), whereas waters mostly affected by saline intrusion did not meet the sodium percentage (Na%), sodium absorption ratio (SAR) and Kelly’s ratio (KR). Heavy groundwater abstraction without regulation is fingered for causing saline intrusion in the area because of reduction of groundwater levels. The hydraulic gradient in the area mimics that of the natural ground level, with relatively gentle slope of 0.002, with the dominant groundwater flow direction of north to south. This work is novel as it sets the tone for the first-ever initial hydrogeological characterisation of the aquifer, whose state can be continuously monitored for advising the Government, and the Water, Agricultural and Health Directorates of the Municipal Assembly for the regulation of agriculture and abstraction in the area, so as to protect the aquifer and human health.
How to cite: Agbotui, P. Y., Amissah, M. B., Ewusi, A., and Woode, A.: A step towards the protection and management of the Shallow Aquifer of the Keta Basin, in Ghana West Africa: an initial physico-chemical characterisation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21834, https://doi.org/10.5194/egusphere-egu25-21834, 2025.
