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Irrigation, one of the 28 agri-environmental indicators defined in the European Common Agricultural Policy, is often neglected in agricultural nitrogen (N) budgets, while it can be a considerable source of N in irrigated agriculture. The annual N input from irrigation water sources (NIrrig) to cropping systems was quantified for Europe for 2000–2010 at a resolution of 10 × 10 km, accounting for crop-specific gross irrigation requirements (GIR) and surface- and groundwater nitrate concentration. GIR were computed for 20 crops, while spatially explicit nitrate concentration in groundwater was derived using a random forest model. We show that although GIR were relatively stable (46–60 km3 yr-1), the Nirrig in Europe increased over the 10-year period (184 to 259 Gg N yr-1), approximately 68 % of which occurred in the Mediterranean region. The main hotspots appeared in areas with both high irrigation requirements and high groundwater nitrate concentration, reaching up to averaged values of 150 kg N ha-1 yr1. These were mainly located in Mediterranean Europe (Greece, Portugal and Spain) and to a lesser extent in Northern Europe (The Netherlands, Sweden and Germany). By not including NIrrig, environmental and agricultural policies are underestimating the real extent of N pollution hotspots in European irrigated systems.

Evolving groundwater vulnerability from DRASTIC to modified DRASTIC methods helps choose the most accurate areas that are most delicate toward pollution. This study aims to modify DRASTIC with land use and water quality index for groundwater vulnerability assessment in the Halabja-Khurmal sub-basin, NE/Iraq. The Halabja-Khurmal sub-basin groundwater vulnerability index is calculated from nine hydrogeological parameters by the overlay weighting method. As a result, 1.3% of the total area has a very high vulnerability value and 46.1% with high vulnerability. The regions with high groundwater vulnerability have a high-water table and groundwater recharge. Nitrate concentration was used to validate the result, and the Pearson correlation and recession analysis between the modified DRASTIC index and nitrate concentration depicted a strong relation with 0.76 and 0.7, respectively., Validerad;2022;Nivå 2;2022-10-31 (johcin)

Increasing farmers' adoption of sustainable nitrogen management practices is crucial for improving water quality. Yet, research to date provides ambiguous results about the most important farmer-level drivers of adoption, leaving high levels of uncertainty as to how to design policy interventions that are effective in motivating adoption. Among others, farmers' engagement in outreach or educational events is considered a promising leverage point for policy measures. This paper applies a Bayesian belief network (BBN) approach to explore the importance of drivers thought to influence adoption, run policy experiments to test the efficacy of different engagement-related interventions on increasing adoption rates, and evaluate heterogeneity of the effect of the interventions across different practices and different types of farms. The underlying data comes from a survey carried out in 2018 among farmers in the Central Valley in California. The analyses identify farm characteristics and income consistently as the most important drivers of adoption across management practices. The effect of policy measures strongly differs according to the nitrogen management practice. Innovative farmers respond better to engagement-related policy measures than more traditional farmers. Farmers with small farms show more potential for increasing engagement through policy measures than farmers with larger farms. Bayesian belief networks, in contrast to linear analysis methods, always account for the complex structure of the farm system with interdependencies among the drivers and allow for explicit predictions in new situations and various kinds of heterogeneity analyses. A methodological development is made by introducing a new validation measure for BBNs used for prediction.

The wine industry produces large quantities of wastewater that often contains high levels of organic matter and nutrients, like nitrogen and phosphorous. In particular, nitrogen pollution can be harmful, even at low levels, since infants are vulnerable to nitrates in drinking water, and excess nitrogen can harm the health of soils and waterways. Herein, an innovative compact, modular, and mobile treatment wetland (TW) using cork by product as the only granular media was used to treat the final effluents from the Codorniu winery (Sant Sadurní d'Anoia, Spain). The TW was operated during two 5-month periods with or without intermittent induced aeration (40 min cycles, 90 L/min air flow rate). Nitrate (N-NO3) and total nitrogen (TN) removal were higher (52.8% and 46.8%, respectively, p < 0.05) during TW operation under aerated-condition. Additionally, qPCR analysis of 16S rRNA, nirS and nosZ genes revealed that intermittent induced aeration facilitates N-NO3 reduction by the stimulation of denitrifying bacteria in the TW biofilm (11.4% increase in nirS copies number/g cork sample, p < 0.05) as well as increasing the number of heterotrophic bacteria adhered to cork (25.5% increase in 16S rRNA copies number/g cork sample, p < 0.05). Moreover, SEM images demonstrated the suitability of cork as a resistant filter media for TW after long-term system operation (1.5 years). In conclusion, our results suggest that aeration improved ni- trogen compounds removal compared to the non-aerated period, without affecting phosphorous elimination. Additionally, residual cork is presented here in a circular bioeconomy view, as a suitable filling media to treat winery wastewater that can provide additional carbon source to increase C/N rate stimulating denitrification, as well as a reliable organic substrate for biomass growth., To LIFE Programme, the EU's financial instrument supporting environmental, nature conservation, and climate action projects throughout the EU that supports LIFE ECORKWASTE 14 ENV/ES/460., Peer Reviewed, Postprint (published version)

El incremento de explotaciones de agricultura y ganadería intensiva está provocando serios impactos sociales y ambientales en gran parte del territorio español. Los sistemas socio-ecológicos de los que depende la industria agroalimentaria necesitan una respuesta jurídica eficaz encaminada a gestionar los riesgos y a proporcionar una respuesta material al modelo de explotación de la llamada “naturaleza extrahumana” (agua, suelos y animales), dirigido, en la mayoría de los casos, a generar “alimentos baratos” a gran escala con destino a mercados internacionales en detrimento de socio-ecosistemas locales como el Mar Menor. La falta de aplicación efectiva del ordenamiento jurídico y de los principios de prevención, precaución y no regresión de la normativa ambiental (ej. códigos de buenas prácticas agrarias y declaración de zonas vulnerables a la contaminación por nitratos), pone en riesgo el territorio y contribuye de manera directa al deterioro y maltrato del medio ambiente a causa, entre otros aspectos, de la contaminación de las masas de aguas (especialmente las subterráneas, costeras y de transición), fruto del incumplimiento constante de la normativa relativa a la contaminación por nitratos procedente de fuentes agrarias y ganaderas., The increase in intensive agriculture and livestock farms is causing serious social and environmental impacts in a large part of the Spanish territory. The socio-ecological systems on which the agri-food industry depends need an effective legal response aimed at managing risks and providing a material response to the model of exploitation of so-called “extra-human nature” (water, soil and animals), aimed, in most cases, at generating large-scale “cheap food” for international markets to the detriment of local socio-ecosystems such as the Mar Menor. The lack of effective application of the legal system and of the principles of prevention, precaution and non-regression of environmental regulations (e.g. codes of good agricultural practice and declaration of areas vulnerable to nitrate pollution), puts the territory at risk and contributes directly to the deterioration and mistreatment of the environment due, among other things, to the pollution of bodies of water (especially groundwater, coastal and transitional waters), as a result of constant non-compliance with regulations on nitrate pollution from agricultural and livestock sources.

Nitrate pollution in groundwater is a serious problem in Shimabara Peninsula, Nagasaki, Japan. A better understanding of the hydrogeochemical evolution of groundwater in vulnerable aquifers is important for health and environment. In this study, groundwater samples were collected at 12 residential and 57 municipal water supply wells and springs in July and August 2018. Nitrate (NO3-N) concentration at eight sampling sites (12%) exceeded Japanese drinking water standard for NO3 + NO2-N (10 mg L-1). The highest nitrate concentration was 19.9 mg L-1. Polluted groundwater is distributed in northeastern, northwestern, and southwestern areas, where land is used for intensive agriculture. Correlation analysis suggests that nitrate sources are agricultural fertilizers and livestock waste. Dominant groundwater chemistry is (Ca+Mg)-HCO3 or (Ca+Mg)-(SO4+NO3) type. Groundwater with higher nitrate concentration is of (Ca+Mg)-(SO4+NO3) type, indicating nitrate pollution affecting water chemistry. Principal component analysis extracted two important factors controlling water chemistry. The first principal component explained dissolved ions through water-rock interaction and agricultural activities. The second principal component explained cation exchange and dominant agricultural effects from fertilizers. Hierarchical cluster analysis classified groundwater into four groups. One of these is related to the dissolution of major ions. The other three represent nitrate pollution., Water, 13(4), art.no.426; 2021

Denitrification in floodplain soils is one key process that determines the buffering capacity of riparian zones in terms of diffuse nitrate pollution. One widely used approach to measure the denitrification potential is the acetylene inhibition technique that requires fresh soil samples. We conducted experiments with air-dried soils using a time series analysis to determine the optimal rewetting period. Thus, air-dried soil samples from six different floodplain areas in Germany were rewetted for 1 to 13days to 100% water-filled pore space. We analyzed nitrogen accumulated as N2O in the top of anaerobic flasks with and without acetylene by gas chromatography after four hours of incubation. We observed an overall optimal rewetting of at least seven days for complete denitrification. We also saw the strong influence of pH and field capacity on the denitrification product ratio; in soils with pH < 7, we hardly assumed complete denitrification, whereas the treatments with pH > 7 achieved stable values after seven days of rewetting. This advanced method provides the opportunity to carry out campaigns with large soil sample sizes on the landscape scale, as samples can be stored dry until measurements are taken.

Nitrate in drinking water may cause serious health problems for consumers. Agricultural activities are known to be the main source of groundwater nitrate contaminating rural domestic and urban public water supply wells in farming regions. Management practices have been proposed to reduce the amount of nitrate in groundwater, including improved nutrient management practices and "pump and fertilize" with nitrate-affected irrigation wells. Here, we evaluate the feasibility and long-term impacts of agricultural managed aquifer recharge (Ag-MAR) in the source area of public water supply wells. A numerical model of nitrate fate and transport was developed for the Modesto basin, part of California's Central Valley aquifer system. The basin is representative of semi-arid agricultural regions around the world with a diversity of crop types, overlying an unconsolidated sedimentary aquifer system. A local public supply well in an economically disadvantaged community surrounded by farmland was the focus of this study. Model scenarios implemented include business as usual, alternative low-impact crops, and Ag-MAR in the source area of the public supply well. Alternative nutrient management and recharge practices act as remediation tools in the area between farmland and the public supply well. Improved agricultural source area management practices are shown to be an effective tool to maintain or even enhance groundwater quality in the targeted supply well while remediating ambient groundwater. Best results are obtained when lowering nitrate load while also increasing recharge in the source area simultaneously. This scenario reduced nitrate in the supply well's drinking water by 80% relative to the business as usual scenario. It also remediated ambient groundwater used by domestic wells between the source area farmlands and the supply well and showed 60% more reduction of nitrate after 60 years of application. Increasing recharge led to shorter initial response time (five years) a

Objectives of the study To implement a statistical data based modelling approach to predict nitrate pollution vulnerability of groundwater in an urban environment. Application to the Brussels Capital Region in Belgium

This dissertation mainly focuses on agricultural policies, water pollution and human health. Chapter.2 examines the causal impact of agricultural water pollution on individual health outcomes. The findings suggest that agricultural water pollution worsens health outcomes and these adverse health effects appear to be largely due to contaminated drinking water. Chapter.3 explores both of the intended wealth effect and unintended pollution effect on human health caused by China’s agricultural support polices. I find that although the income effect dominates on reducing the overall sickness, the pollution effect is more substantial on the diarrhea incidence and adult BMI. Income affects slightly higher than pollution on adults' overall health, while pollution has higher impacts on children's overall health. Chapter.4 builds a dynamic optimization model internalizing the health cost of agricultural water pollution. My simulation results suggest that policymakers should manage fertilizer application rates based on the initial nitrate concentration levels.

Agricultural practices have raised the level of nutrients reaching aquifers. In Europe, nitrate 24 pollution is considered as one of the main threats for the quality of groundwater in agricultural 25 areas. Treatment wetlands (TWs), also known as Constructed Wetlands, are used for 26 groundwater treatment in areas with an important concentrations of nitrogen compounds; total 27 nitrogen removal depends on the type and operation scheme. Cork by-product from the 28 industry has shown clear adsorbent properties to remove organic pollutants. The work is 29 focused on the characterization of microbial communities involved in the nitrate-nitrogen 30 removal process in groundwater polluted from agricultural activities. The experimental design 31 allowed the comparison of nitrate removal efficiency depending on the filter media material, 32 cork by-product or gravel, used in two hybrid TWs (a vertical flow cell followed by a horizontal 33 subsurface flow cell), installed in areas close to two irrigated agricultural plots at the Lleida plain 34 area (Spain). Both physicochemical and microbial results were consistent and confirm the nitrate 35 removal efficiency using cork as a filter media. A significant (p=0.0025) higher removal in Bellvís 36 TW using cork compared with the Vilanova de la Barca gravel system was observed, achieving a 37 removal rate from 80 to 99% compared to the 5-46%, respectively. Regarding the community 38 composition of the two different TWs, microorganisms were mainly related to the phylum 39 Proteobacteria, and included members found to be key players in the nitrogen cycle, such as 40 ammonia and nitrite oxidizers, as well as denitrifiers. Also, the group Bacteroidetes turn to be 41 another abundant phylum from our bacterial dataset, whose members are suggested to be 42 strongly involved in denitrification processes. Some groups showed to prevail depending on the 43 type of media (cork or gravel); Firmicutes and Delta and Epsilonproteobacteria had a

Agricultural practices have raised the level of nutrients reaching aquifers. In Europe, nitrate pollution is considered as one of the main threats for the quality of groundwater in agricultural areas. Treatment wetlands (TWs), also known as Constructed Wetlands, are used for groundwater treatment in areas with an important concentration of nitrogen compounds; total nitrogen removal depends on the type and operation scheme. Cork by-product from the industry has shown clear adsorbent properties to remove organic pollutants. The work is focused on the characterization of microbial communities involved in the nitrate‑nitrogen removal process in groundwater polluted from agricultural activities. The experimental design allowed the comparison of nitrate removal efficiency depending on the filter media material, cork by-product or gravel, used in two hybrid TWs (a vertical flow cell followed by a horizontal subsurface flow cell), installed in areas close to two irrigated agricultural plots at the Lleida plain area (Spain). Both physicochemical and microbial results were consistent and confirm the nitrate removal efficiency using cork as a filter media. A significant (p = 0.0025) higher removal in Bellvís TW using cork compared with the Vilanova de la Barca gravel system was observed, achieving a removal rate from 80 to 99% compared to the 5–46%, respectively. Regarding the community composition of the two different TWs, microorganisms were mainly related to the phylum Proteobacteria, and included members found to be key players in the nitrogen cycle, such as ammonia and nitrite oxidizers, as well as denitrifiers. Also, the group Bacteroidetes turns to be another abundant phylum from our bacterial dataset, whose members are suggested to be strongly involved in denitrification processes. Some groups showed to prevail depending on the type of media (cork or gravel); Firmicutes and Delta and Epsilonproteobacteria had a significant higher abundance in the TW with cork, while Ac

Groundwater is a crucial natural resources supporting the development of the African continent, but it is subjected to many pressures. Therefore, to support Africa policy in groundwater management in such context, it is important to identify which aquifer systems/groundwater resources and settings are most vulnerable to degradation and factors which contributes to nitrate pollution.

The cover crop (CC) termination date (TD) is a key management tool to enhance some of CC benefits such as soil water conservation and N recycling, and to minimize risks as the pre-emptive competition of CC with subsequent cash crops. However, the optimum date depends on annual meteorological conditions, and climate variability induces uncertainty in a decision that needs to be taken every year. One of the most important cover crop benefits is reducing nitrate leaching, a major concern for irrigated agricultural systems and highly affected by the termination date. This study aimed to determine the effects of cover crops and their termination date on the water and N balances of an irrigated Mediterranean agroecosystem under present and future climate conditions. Understanding the TD management in different scenarios and climatic conditions would be useful to achieve efficient management strategies.

Groundwater is a finite resource that is threatened by pollution all over the world. Shimabara City, Nagasaki, Japan, uses groundwater for its main water supply. During recent years, the city has experienced severe nitrate pollution in its groundwater. For better understanding of origin and impact of the pollution, chemical effects and surface?groundwater interactions need to be examined. For this purpose, we developed a methodology that builds on joint geochemical analyses and advanced statistical treatment. Water samples were collected at 42 sampling points in Shimabara including a part of Unzen City. Spatial distribution of water chemistry constituents was assessed by describing Stiff and Piper diagrams using major ions concentrations. The nitrate (NO3 + NO2?N) concentration in 45% of water samples exceeded permissible Japanese drinking level of 10 mg L? 1. Most of the samples showed Ca?HCO3 or Ca?(NO3 + SO4) water types. Some samples were classified into characteristic water types such as Na?Cl, (Na + K)?HCO3, (Na + K)?(SO4 + NO3), and Ca?Cl. Thus, results indicated salt water intrusion from the sea and anthropogenic pollution. At the upstream of Nishi River, although water chemistry was characterized as Ca?HCO3, ion concentrations were higher than those of other rivers. This is probably an effect of disinfection in livestock farming using slaked lime. Positive correlation between NO3 ? and SO4 2?, Mg2+, Ca2+, Na+, K+, and Cl? (r = 0.32?0.64) is evidence that nitrate pollution sources are chemical fertilizers and livestock waste. Principal component analysis showed that chemistry of water samples can be explained by three main components (PCs). PC1 depicts general ion concentration. PC2 and PC3 share influence from chemical fertilizer and livestock waste. Cluster analyses grouped water samples into four main clusters. One of these is the general river chemistry mainly affected by PC1. The others reflect anthropogenic activities and are identified by the combinat, Environmental Earth Sciences, 77(9), 354; 2018

Global change effects, such as warming and increases in nitrogen loading, alter vulnerable Mediterranean aquatic systems, and charophytes can be one of the most affected groups. We addressed the possible interaction between these factors on two populations of the cosmopolitan charophytes Chara hispida and Chara vulgaris. Populations were taken from two different environments, a nitrate-poor mountain lake and a nitrate-rich Mediterranean coastal spring. The laboratory experiment had a 2 × 2 factorial design based on two nitrate levels (similar to and double the local conditions) and two temperatures. Increased temperatures favoured the growth of the four populations, but an increase in nitrate did not have any effect on their growth or architecture. Both species took up and stored more nitrogen (measured as %N in plant tissue) when more nitrate was supplied, and warming favoured this increase in %N and, consequently, in N:P ratio. The effects of both factors depended on the local conditions where the populations originated and on the species. Chara vulgaris, a pioneer species, exhibited more phenotypic plasticity than C. hispida, and its ecotype from the coastal spring was better adapted to changes in temperature and nitrate level. These differential responses to warming conditions and nitrate pollution may modify charophyte diversity, which might be reflected in ecosystem performance, a matter of concern in vulnerable Mediterranean water bodies where these species co-occur.

Assessing groundwater vulnerability is key to monitor the implementation of the UN SDG for water. We therefore studied in this thesis groundwater vulnerability for pollution at the African scale. The first main objective was to map groundwater vulnerability to pollution at the African scale by applying DRASTIC index. Best available datasets for land use, soil, topography, geology and hydrogeology were collected from different sources. We compiled these data into a 15x15 km2 resolution geodatabase for the continent and used to build the variables of the DRASTIC index. This resulted in the first pan-African groundwater vulnerability and pollution risk map. The map shows that areas under very high and high pollution risk are mainly characterised by shallow groundwater. In second main objective we developed a statistical model to identify environmental variables that explain pollution in groundwater at the African scale. Through a meta-analysis, we compiled a literature database of nitrate contamination. Two statistical models were used to link nitrate and environmental variables and demonstrated the unambiguous link between population density and nitrate pollution. We recalibrated and validated these statistical models using regional datasets of nitrate measured in groundwater. In last main objective, we integrated the time dynamics in the DRASTIC index, focussing on the time dynamics of population density and climate as drivers of groundwater pollution. This approach demonstrated that the groundwater vulnerability to pollution across Africa varies indeed considerably in time, in particularly in densely populated areas in West Africa, the Nile delta, and urbanised regions in East and southern Africa., (AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 2017

This work presents the evolution, over a year, of nitrate content in the groundwater of the western area of La Hoya de Huesca. The observation of 21 water points indicates that the groundwater of the studied area normally exceeds 50 mg/L of nitrate ion. It also confirms the existence of an old problem of diffuse contamination., En este artículo se presenta la evolución, durante un año, del contenido de nitratos en las aguas subterráneas de la zona occidental de la Hoya de Huesca. A partir de 21 puntos de agua se constata que, en general, las aguas subterráneas de la zona estudiada superan los 50 mg/L de ion nitrato. Se comprueba la existencia de un viejo problema de contaminación difusa.

Elevated nitrate concentrations are a thread for water supply and ecological integrity in surface water. Nitrate fluxes obtained by standard monitoring protocols at the catchment outlet strongly integrate spatially and temporally variable processes such as mobilization and turnover. Consequently, inference of dominant nitrate sources is often problematic and challenging in terms of effective river management and prioritization of measures. Here, we combine a spatially highly resolved assessment of nitrate concentration and fluxes along a mesoscale catchment with four years of monitoring data at two representative sites. The catchment is characterized by a strong land use gradient from pristine headwaters to lowland sub-catchments with intense agricultural land use and wastewater sources. We use nitrate concentrations in combination with hydrograph separation and isotopic fingerprinting methods to characterize and quantify nitrate source contribution.The hydrological analysis revealed a clear dominance of base flow during both campaigns. However, the absolute amounts of discharge differed considerably from one another (outlet: 1.42 m3 s− 1 in 2014, 0.43 m3 s− 1 in 2015). Nitrate concentrations are generally low in the pristine headwaters (< 3 mg L− 1) and increase downstream (15 to 16 mg L− 1) due to the contribution of agricultural and wastewater sources. While the agricultural contribution did not vary in terms of nitrate concentration and isotopic signature between the years, the wastewater contribution strongly increased with decreasing discharge. Wastewater-borne nitrate load in the entire catchment ranged between 19% (2014) and 39% (2015). Long-term monitoring of nitrate concentration and isotopic composition in two sub-catchment exhibits a good agreement with findings from spatially monitoring. In both datasets, isotopic composition indic

Groundwater contamination by nitrate is a common problem in many parts of the world. The agriculturally important Shimabara district in Nagasaki, Japan, is experiencing this problem. The general source of drinking water of the study area is groundwater and consequently the nitrate contamination is a significant problem. For this reason, a groundwater investigation was performed and water samples were collected at 40 locations including residential areas, public water supply wells, springs, and rivers from August 2011 to November 2013. Results showed that nitrate nitrogen (NO3-N) concentration is exceeding the Japanese drinking water quality standards (10 mg L?1) at 15 locations. Maximum NO3-N concentration was 26.6 mg L?1. Nitrate (NO?3) was strongly correlated with Cl? (r = 0.96), K+ (r = 0.68), SO2?4 (r = 0.66), and Ca2+ (r = 0.59), respectively. The high correlations with Cl? and K+ are related to livestock waste. Corresponding correlation with SO2?4 is related to chemical fertilizers and Ca2+ to calcareous material to neutralize acidic soil. Both the first and second components in principal component analysis reflect ion dissolution from aquifer matrix during groundwater flow along the mountain side towards the lower reaches of the alluvial fan. Using hierarchical cluster analysis, chemical characteristics of groundwater were classified into four clusters. One cluster is strongly related to the nitrate contaminated groundwater and the other clusters reflect the origin of the major ions in the groundwater., Environmental Earth Sciences, 75(3), art. no.234; 2016

Contamination from agricultural sources and, in particular, nitrate pollution, is one of the main concerns in groundwater management. However, this type of pollution entails the entrance of other substances into the aquifer, as well as it may promote other processes. In this study, we deal with hydrochemical and isotopic analysis of groundwater samples from four distinct zones in Catalonia (NE Spain), which include 5 different aquifer types, to investigate the influence of fertilization on the overall hydrochemical composition of groundwater. Results indicate that intense fertilizer application, causing high nitrate pollution in aquifers, also homogenize the contents of the major dissolved ions (i.e.; Cl(-), SO4(2-), Ca(2+), Na(+), K(+), and Mg(2+)). Thus, when groundwater in igneous and sedimentary aquifers is compared, significant differences are observed under natural conditions for Cl(-), Na(+) and Ca(2+) (with p-values ranging from <0.001 to 0.038), and when high nitrate concentrations occur, these differences are reduced (most p-values ranged between 0.054 and 0.978). Moreover, positive linear relationships between nitrate and some ions are found indicating the magnitude of the fertilization impact on groundwater hydrochemistry (with R(2) values of 0.490, 0.609 and 0.470, for SO4(2-), Ca(2+) and Cl(-), respectively). Nevertheless, the increasing concentration of specific ions is not only attributed to agricultural pollution, but to their enhancing effect upon the biogeochemical processes that control water-rock interactions. Such results raise awareness that these processes should be evaluated in advance in order to assess an adequate groundwater resources management., Peer Reviewed, Postprint (author's final draft)

In the present study an overlay method to assess groundwater vulnerability is proposed. This new method based on multicriteria decision analysis (MCDA) was developed and validated using an appropriate case study in Aragon area (NE Spain). The Vulnerability Index to Nitrates from Agricultural Sources (VINAS) incorporates a novel Logic Scoring of Preferences (LSP) approach, and it has been developed using public geographic information from the European Union. VINAS-LSP identifies areas with five categories of vulnerability, taking into account the hydrogeological and environmental characteristics of the territory as a whole. The resulting LSP map is a regional screening tool that can provide guidance on the potential risk of nitrate pollution, as well as highlight areas where specific research and farming planning policies are required., In the present study an overlay method to assess groundwater vulnerability is proposed. This new method based on multicriteria decision analysis (MCDA) was developed and validated using an appropriate case study in Aragon area (NE Spain). The Vulnerability Index to Nitrates from Agricultural Sources (VINAS) incorporates a novel Logic Scoring of Preferences (LSP) approach, and it has been developed using public geographic information from the European Union. VINAS-LSP identifies areas with five categories of vulnerability, taking into account the hydrogeological and environmental characteristics of the territory as a whole. The resulting LSP map is a regional screening tool that can provide guidance on the potential risk of nitrate pollution, as well as highlight areas where specific research and farming planning policies are required., Postprint (published version)

La aplicación de sistemas de información geográfica (SIG) en el ámbito de las ciencias ambientales es cada vez mayor, como así se demuestra en la elevada cantidad de estudios en hidrología, edafología, gestión forestal, impacto ambiental, contaminación ambiental, auditoría ambiental, etc. Las aguas superficiales y subterráneas en el litoral de la Comunitat Valenciana se ven afectadas por la intrusión marina y por la contaminación por nitratos. En el siguiente proyecto se aplicarán los SIG para cartografiar la calidad de las aguas en la comarca de La Safor. Se generarán cartografías de distribución de cloruros y nitratos para analizar la situación de la comarca detectando zonas críticas y aptas. Aplicando superposición espacial entre las diferentes cartografías se va a estudiar la evolución de estas variables a lo largo del tiempo y finalmente se intentará proponer alternativas para que la situación se dirija al mejor estado ambiental posible., The application of geographical information systems (GIS) in environmental science field is constantly increasing such as studies of hydrology, soil science, forest management, environmental studies, etc. GIS techniques were applied in this project for mapping the quality of waters in the Safor region. This region is localized in the coast of Valencian region and both surface and ground waters are affected by marine intrusion and nitrate pollution. Cartography of distribution of those variables was generated for detecting critical and suitable regions. Spatial overlapping analysis was applied among different cartographies to study the evolution and finally some actuations will be proposed for achieving the best environmental situation.

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Groundwater is a crucial natural resource supporting the development of the African continent, but it is subjected to many pressures. According to Xu and Usher, (2006), degradation of groundwater is the most serious water resources problem in Africa. Nitrate is a common groundwater contaminant and a good indicator of the anthropogenic degradation of groundwater quality. Statistical models can be deployed to predict the spatial distribution of nitrate in groundwater in terms of environmental and anthropogenic attributes. The purpose of this study is to identify such a statistical model to map nitrate contamination in groundwater at the pan African scale, supporting regional groundwater quality monitoring programs.

The paper shows the hydrochemistry at 39 points of sur-ficial and underground waters near the city of Huesca. Most water samples show similar characteristics given the general presence of limestone in the whole area. The samples from natural areas show a low level of nitrate ion from natural sources. The nitrate concentration is high in the dry farming area, but lower in the land irrigated with the water of the Isuela River., El presente artículo estudia la hidroquímica de 39 puntos de aguas superficiales y subterráneas situados en las cercanías de la ciudad de Huesca. La mayoría de las muestras tienen características similares, dada la presencia generalizada de caliza en toda la zona. En las muestras de áreas naturales hay un bajo nivel de nitratos de origen natural. El nivel de nitratos es elevado en la zona de agricultura de secano, pero menor en las zonas rega-das por el río Isuela.

Three Tertiary aquifers and one Mesozoic aquifer located in the two neighbouring Autonomous Communities of Madrid and Castilla-La Mancha (central Spain) were selected to study the environmental factors affecting groundwater pollution by nitrate. The majority of the territory was subject to a very high degree of human impact, with it being difficult to identify which potential sources of nitrogen were responsible for the observed cases of groundwater nitrate pollution. The objectives were: (1) to obtain a better understanding of nitrate distribution in the aquifers during a period of 25 years; (2) to determine the relative contribution of several environmental parameters (including land use) that are often used in groundwater vulnerability assessment using principal components analysis (PCA); (3) to make a critical review of the current criteria used for the designation of nitrate vulnerable zones (NVZs; Directive 91/676/EEC) in this territory; and (4) to discuss the concept of groundwater vulnerability to nitrate vs. groundwater nitrate pollution. Contour maps of nitrate contents in the four aquifers from 1985 to 2010 showed a persistent problem of nitrate pollution affecting wide areas of the Tertiary aquifers (subjected to a high risk of anthropogenic impact), whereas the Mesozoic aquifer remained unpolluted (protected by non-polluting land uses). The PCA demonstrated that the main risk of groundwater nitrate pollution stemmed from the interaction between intrinsic vulnerability (related to hydrogeological factors and soil media) and land use; and this, together with groundwater flow, allowed us to explain the possible sources of nitrogen at each sampling point. The current demarcations of NVZs in central Spain reveal a lack of coordination between administrations and poorly defined criteria. Our results show the need to redefine these NVZs by mapping vulnerability to nitrate pollution within this territory based on the environmental factors highlighted by the PCA

In this paper a methodology for the stochastic management of groundwater quality problems is presented, which can be used to provide agricultural advisory services. A stochastic algorithm to solve the coupled flow and mass transport inverse problem is combined with a stochastic management approach to develop methods for integrating uncertainty; thus obtaining more reliable policies on groundwater nitrate pollution control from agriculture. The stochastic inverse model allows identifying non-Gaussian parameters and reducing uncertainty in heterogeneous aquifers by constraining stochastic simulations to data. The management model determines the spatial and temporal distribution of fertilizer application rates that maximizes net benefits in agriculture constrained by quality requirements in groundwater at various control sites. The quality constraints can be taken, for instance, by those given by water laws such as the EU Water Framework Directive (WFD). Furthermore, the methodology allows providing the trade-off between higher economic returns and reliability in meeting the environmental standards. Therefore, this new technology can help stakeholders in the decision-making process under an uncertainty environment. The methodology has been successfully applied to a 2D synthetic aquifer, where an uncertainty assessment has been carried out by means of Monte Carlo simulation techniques. (c) 2014 Elsevier B.V. All rights reserved.

Drinking water in Kinshasa, the capital of the Democratic Republic of Congo, is provided by extracting groundwater from the local aquifer, particularly in peripheral areas. The exploited groundwater body is mainly unconfined and located within a continuous detrital aquifer, primarily composed of sedimentary formations. However, the aquifer is subjected to an increasing threat of anthropogenic pollution pressure. Understanding the detailed origin of this pollution pressure is important for sustainable drinking water management in Kinshasa. The present study aims to explain the observed nitrate pollution problem, nitrate being considered as a good tracer for other pollution threats. The analysis is made in terms of physical attributes that are readily available using a statistical modelling approach. For the nitrate data, use was made of a historical groundwater quality assessment study, for which the data were re-analysed. The physical attributes are related to the topography, land use, geology and hydrogeology of the region. Prior to the statistical modelling, intrinsic and specific vulnerability for nitrate pollution was assessed. This vulnerability assessment showed that the alluvium area in the northern part of the region is the most vulnerable area. This area consists of urban land use with poor sanitation. Re-analysis of the nitrate pollution data demonstrated that the spatial variability of nitrate concentrations in the groundwater body is high, and coherent with the fragmented land use of the region and the intrinsic and specific vulnerability maps. For the statistical modeling use was made of multiple regression and regression tree analysis. The results demonstrated the significant impact of land use variables on the Kinshasa groundwater nitrate pollution and the need for a detailed delineation of groundwater capture zones around the monitoring stations.

A strong normative development in Europe, including the Nitrate Directive (1991) and the Water Framework Directive (WFD) (2000), has been promulgated. The WFD states that all water bodies have to reach a good quantitative and chemical status by 2015. It is necessary to consider different objectives, often in conflict, for tackling a suitable assessment of the impacts generated by water policies aimed to reduce nitrate pollution in groundwater. For that, an annual lumped probabilistic model based on Bayesian networks (BNs) has been designed for hydro-economic modelling of groundwater quality control under uncertain conditions. The information introduced in the BN model comes from different sources such as previous groundwater flow and mass transport simulations, hydro-economic models, stakeholders and expert opinion, etc. The methodology was applied to the El Salobral–Los Llanos aquifer unit within the ‘Easter Mancha’ groundwater body, which is one of the largest aquifers in Spain (7,400 km2), included in the Júcar River Basin. Over the past 30 years, socioeconomic development within the region has been mainly depending on intensive use of groundwater resources for irrigating crops. This has provoked a continuous groundwater level fall in the last two decades and significant streamflow depletion in the connected Júcar River. This BN model has proved to be a robust Decision Support System for helping water managers in the decision making process

A strong normative development in Europe, including the Nitrate Directive (1991) and the Water Framework Directive (WFD) (2000), has been promulgated. The WFD states that all water bodies have to reach a good quantitative and chemical status by 2015. It is necessary to consider different objectives, often in conflict, for tackling a suitable assessment of the impacts generated by water policies aimed to reduce nitrate pollution in groundwater. For that, an annual lumped probabilistic model based on Bayesian networks (BNs) has been designed for hydro-economic modelling of groundwater quality control under uncertain conditions. The information introduced in the BN model comes from different sources such as previous groundwater flow and mass transport simulations, hydro-economic models, stakeholders and expert opinion, etc. The methodology was applied to the El Salobral-Los Llanos aquifer unit within the 'Easter Mancha' groundwater body, which is one of the largest aquifers in Spain (7,400 km(2)), included in the Júcar River Basin. Over the past 30 years, socioeconomic development within the region has been mainly depending on intensive use of groundwater resources for irrigating crops. This has provoked a continuous groundwater level fall in the last two decades and significant streamflow depletion in the connected Júcar River. This BN model has proved to be a robust Decision Support System for helping water managers in the decision making process.

Groundwater availability depends on its accessibility, as well as on its quality. A principal component analysis (PCA) has been used to link the occurrence of natural (fluoride) and human (nitrate) pollutants with the hydrological dynamics in the Selva Basin (NE Spain) as a means to analyze quality problems and provide strategies for water resources exploitation. Statistical results show that both pollutants are independent, and they are related to groundwater fluxes of different spatial scales. Fluoride is linked to regional groundwater systems, while nitrate is related to local recharge produced within the basin. PCA thus permits relating a potential occurrence of pollutants to specific characteristics of the hydrogeological system. It also becomes an approach to assess its vulnerability by identifying key parameters related to pollution. Such a statistical outcome is of interest for water resources planning with the aim to avoid locating production wells in areas that show hydrogeological or hydrochemical features associated with either type of pollution., Peer Reviewed, Postprint (published version)

The causes of interannual nitrate variability in rivers remain uncertain, but extreme climatic events have been suggested as drivers of large nitrate inputs to rivers. Based on a 24-year data set (1983-2006), we suggest that El Niño-Southern Oscillation (ENSO) can affect nitrate behavior in a seasonal extra-tropical stream, the Llobregat (NE Iberian Peninsula), located thousands of kilometers away from the ENSO oscillating system via atmospheric teleconnections. Two commonly used indices, the Southern Oscillation Index (SOI) and the self-calibrating-Palmer Drought Severity Index (scPDSI) showed highly significant correlations with nitrate concentrations, which recurrently increased during La Niña phases, coinciding with severe droughts. © 2012 Elsevier B.V.

[EN] In decision-making processes, reliability and risk aversion play a decisive role. This paper presents a framework for stochastic optimization of control strategies for groundwater nitrate pollution from agriculture under hydraulic conductivity uncertainty. The main goal is to analyze the influence of uncertainty in the physical parameters of a heterogeneous groundwater diffuse pollution problem on the results of management strategies, and to introduce methods that integrate uncertainty and reliability in order to obtain strategies of spatial allocation of fertilizer use in agriculture. A hydro-economic modeling approach is used for obtaining the allocation of fertilizer reduction that complies with the maximum permissible concentration in groundwater while minimizes agricultural income losses. The model is based upon nonlinear programming and groundwater flow and mass transport numerical simulation, condensed on a pollutant concentration response matrix. The effects of the hydraulic conductivity uncertainty on the allocation of nitrogen reduction among agriculture pollution sources are analyzed using four formulations: Monte Carlo simulation with pre-assumed parameter field, Monte Carlo optimization, stacking management, and mixed-integer stochastic model with predefined reliability. The formulations were tested in an illustrative example for 100 hydraulic conductivity realizations with different variance. The results show a high probability of not meeting the groundwater quality standards when deriving a policy from just a deterministic analysis. To increase the reliability several realizations can be optimized at the same time. By using a mixed-integer stochastic formulation, the desired reliability level of the strategy can be fixed in advance. The approach allows deriving the trade-offs between the reliability of meeting the standard and the net benefits from agricultural production. In a risk-averse decision making, not only the reliability of meeting the

[EN] Although the legislation on groundwater quality targets pollutant concentration, the effects of measures on non-point source pollution control are often evaluated in terms of their emission reduction potential at the source, not on their capacity of reducing the pollutant concentration in groundwater. This paper applies a hydro-economic modelling framework to an aquifer, El Salobral-Los Llanos aquifer (Mancha Oriental, Spain), where nitrate concentrations higher than those allowed by the EU Water Framework Directive and Groundwater Directive are locally found due to the intense fertilizer use in irrigated crops. The approach allows defining the economically optimal allocation of spatially variable fertilizer standards in agricultural basins using a hydro-economic model that links the fertilizer application with groundwater nitrate concentration at different control sites while maximizing net economic benefits. The methodology incorporates results from agronomic simulations, groundwater flow and transport into a management framework that yields the fertilizer allocation that maximizes benefits in agriculture while meeting the environmental standards. The cost of applying fertilizer standards was estimated as the difference between the private net revenues from actual application and the scenarios generated considering the application of the standards. Furthermore, the cost of applying fertilizer standards was compared with the cost of taxing nitrogen fertilizers in order to reduce the fertilizer use to a level that the nitrate concentration in groundwater was below the limit. The results show the required reduction of fertilizer application in the different crop areas depending on its location with regards to the control sites, crop types and soil-plant conditions, groundwater flow and transport processes, time horizon for meeting the standards, and the cost of implementing such a policy (as forgone benefits). According to the results, a high fertilizer price wo

[1] Nitrate pollution from agricultural activities often persistently affects groundwater quality due to long residence times in the vadose and saturated zone. In this study we used a lumped parameter approach to estimate the residence time of groundwater and nitrate from the agriculturally used Jahna-Aue drinking water catchment in Saxonia, Germany. Inverse modeling of measured concentrations of tritium and tritiogenic 3He revealed consistent mean residence times between 25 and 50 years for the young, nitrate-rich groundwater component, and high contributions (>75%) of an old, tracer-free, and nitrate-poor groundwater. The obtained age distributions are in accordance with the complex hydrogeological situation of the investigated catchment, suggesting that the shallow and therefore most vulnerable part of the aquifer is not connected to the production wells. High residence times are supported by low concentrations of CFCs and by radiogenic 4He as an independent age indicator. CFC concentrations only yield lower age limits due to identified problems with CFC contamination. Using the tracer-calibrated age distributions, future nitrate concentrations in the production wells most probably will remain below the drinking water limit because of the high dilution with old, nitrate-poor groundwater. Deterioration of the groundwater quality with respect to nitrate may occur if the groundwater pumping regime is changed so that the fraction of the younger, nitrate-bearing water is increased.

The effects of applying different commercial, controlled release fertilizers (CRF) as a means of controlling NO3- pollution of groundwater in an irrigated maize crop were tested. The polluting effects of two sources of irrigation water with different NO3- content were also evaluated. The results showed that conventional agricultural practices are one of the main causes of NO3-aquifer pollution. Excess nitrogenous fertilization occurs because of the lack of soil monitoring to rationalize the fertilizer dosages and because the flood irrigation system, used with the frequency and rates applied, accelerates NO3- leaching. The results also show the inefficient use made of water. An analysis of the results, using the evolution of the NOa- leaching rate, proved to be a more reliable source of information for assessing pollution than the concentrations detected in the soil water solution, below the root zone when the water flow was downwards. The use of two different sources of irrigation water (well, 43 mg NO3-l-1 and stream, 3 mg NO3-l-1) showed no significant differences on the NO3- leached during the maize growing period owing to the high levels detected in the soil and the high dosages of N applied. In the stream irrigation water experiment, a greater polluting effect was observed with conventional fertilizer application (urea) than with CRF. The results obtained with Floranid 32 showed the effects of control over NO3- leaching both in the case of stream and well-water irrigation sources. With Multicote this is only observed with the use of NO3- free water.