USE OF STABLE ISOTOPES IN THE DETERMINATION OF THE MEAN ALTITUDE OF RECHARGE AND THE INVESTIGATION OF FUNCTION MECHANISM OF SPRING WATERS IN ARGOLIS PENINSULA (GREECE)

In the present study, the isotopic composition (δ18Ο) of several spring waters in Argolis peninsula is examined. The use of the specific isotope aimed at the determination of the altitude of recharge areas, while the credibility of the extracted results was verified by in situ geological observations. The applied methodology included the construction of a linear diagram which correlates the stable isotopic values (δ18Ο) in meteoric waters and the altitude. Isotopic data, concerning meteoric waters, came from: a) rain gauge stations of GNIP network (IAEA/WMO), b) rain tanks and selected wells located in Mt. Arachnaio, c) improvised rain collectors which were put in several sites in the peninsula. A decrease of 0.45‰ δ18Ο per 100m altitude was determined. The average isotopic composition of the examined springs, as far as δ18Ο is concerned, resulted from 14 sampling periods between October 2005 and March 2008. This 18O-content of spring waters was used to derive the recharge area and consequently to evaluate the mechanism of water renewal

Corporate Social Responsibility in a context of sustainable development

“The future we want”, the main document summarizing the action areas advocated by the Rio+20 conference (Rio de Janeiro, Brazil, June 20-22nd), advocates “green economy” as a main instrument to eradicate poverty, while maintaining the healthy functioning of the environment. “Green economy” is a reply to global capitalism and the excesses of its elite practitioners, as they became manifest during the recent economic crisis. A classical contribution of the private business sector to sustainable development is corporate social responsibility (CSR). The concept dovetails in the doctrine that a company is not only responsible for a positive economic performance, but also has to take care about the environmental, social and ethical aspects of its activities. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3164

Global patterns of nitrate isotope composition in rivers and adjacent aquifers reveal reactive nitrogen cascading

Remediation of nitrate pollution of Earth’s rivers and aquifers is hampered by cumulative biogeochemical processes and nitrogen sources. Isotopes (δ15N, δ18O) help unravel spatiotemporal nitrogen(N)-cycling of aquatic nitrate (NO3−). We synthesized nitrate isotope data (n = ~5200) for global rivers and shallow aquifers for common patterns and processes. Rivers had lower median NO3− (0.3 ± 0.2 mg L−1, n = 2902) compared to aquifers (5.5 ± 5.1 mg L−1, n = 2291) and slightly lower δ15N values (+7.1 ± 3.8‰, n = 2902 vs +7.7 ± 4.5‰, n = 2291), but were indistinguishable in δ18O (+2.3 ± 6.2‰, n = 2790 vs +2.3 ± 5.4‰, n = 2235). The isotope composition of NO3− was correlated with water temperature revealing enhanced N-cascading in warmer climates. Seasonal analyses revealed higher δ15N and δ18O values in wintertime, suggesting waste-related N-source signals are better preserved in the cold seasons. Isotopic assays of nitrate biogeochemical transformations are key to understanding nitrate pollution and to inform beneficial agricultural and land management strategies

Nitrate source identification in groundwater of multiple land-use areas by combining isotopes and multivariate statistical analysis: A case study of Asopos basin (Central Greece)

Nitrate (NO3) is one of the most common contaminants in aquatic environments and groundwater. Nitrate concentrations and environmental isotope data (d15N-NO3 and d18O-NO3) from groundwater of Asopos basin, which has different land-use types, i.e., a large number of industries (e.g., textile, metal processing, food, fertilizers, paint), urban and agricultural areas and livestock breeding facilities, were analyzed to identify the nitrate sources of water contamination and N-biogeochemical transformations. A Bayesian isotope mixing model (SIAR) and multivariate statistical analysis of hydrochemical data were used to estimate the proportional contribution of different NO3 sources and to identify the dominant factors controlling the nitrate content of the groundwater in the region. The comparison of SIAR and Principal Component Analysis showed that wastes originating from urban and industrial zones of the basin are mainly responsible for nitrate contamination of groundwater in these areas. Agricultural fertilizers and manure likely contribute to groundwater contamination away from urban fabric and industrial land-use areas. Soil contribution to nitrate contamination due to organic matter is higher in the south-western part of the area far from the industries and the urban settlements. The present study aims to highlight the use of environmental isotopes combined with multivariate statistical analysis in locating sources of nitrate contamination in groundwater leading to a more effective planning of environmental measures and remediation strategies in river basins and water bodies as defined by the European Water Frame Directive (Directive 2000/60/EC). © 2015 Elsevier B.V

Application of stable isotopes and hydrochemical analysis in groundwater aquifers of Argolis Peninsula (Greece)

The present study examines the isotopic and hydrochemical composition of 18 inland spring waters and 3 coastal karstic spring waters, covering the period between October 2005 and March 2008. The stable isotopes ( 18O, 2H) processing has revealed the absence of significant evaporation phenomena and that the origin of fresh water samples is meteoric. Using 18O values in rainfall waters, an average line of isotopic depletion with altitude has been constructed, extracting a rate of-0.45‰/100 m as typical for the study area. Furthermore, the mean altitude of recharge of the springs has been estimated by plotting the groundwater sampling points on a δ 18O versus altitude diagram. Hydrochemistry results have shown that the dissolution of carbonate, flysch and ophiolitic formations defines the hydrochemical characteristics of groundwater. Moreover, seawater intrusion in the coastal area is significantly high, causing the water in the three karstic springs to be brackish. © 2011 Copyright Taylor and Francis Group, LLC

Stable isotope patterns reveal widespread rainy-period-biased recharge in phreatic aquifers across Greece

The stable isotopic composition of water (δ18O, δ2H) is used to trace different components of the hydrological cycle, particularly interactions between precipitation, surface, and ground water. In Greece, insufficient spatial coverage for isotopes in precipitation hinders investigations of relationship between ground water and precipitation, information that is required to help quantify aquifer replenishment rates. We used precipitation, geospatial, ground water isotope data and General Linear Models (GLM) to predict the spatial distribution of isotopes in phreatic ground water in Greece. Prediction covariates of elevation, latitude, distance to nearest coastline, drainage basin (western vs. eastern Greece), and amount of precipitation predicted 62% of the isotopic variance in ground water. The GLM model yielded predictions of the isotopic composition of shallow aquifers, which allowed us to construct maps for use in hydrological and other forensic applications in Greece. A comparison of the stable isotope values predicted by our GLM to those of existing precipitation models revealed that phreatic aquifers in Greece are mainly recharged during the annual wet period, between November and March, as documented by the high overlap coefficients of 0.77 and 0.82, respectively. Rainy-period-biased aquifer recharge has implications for water quality and management issues, for example, nitrate pollution may be enhanced in the non-growing rainy period when crop uptake is the lowest, or for water resource management if climatic changes alter these temporal rainfall patterns. © 2018 Elsevier B.V

Performance Evaluation of Multiple Groundwater Flow and Nitrate Mass Transport Numerical Models

Benchmarking of different numerical models simulating groundwater flow and contaminant mass transport is the aim of the present study, in order to determine criteria for the selection of numerical model(s) that could be better tailored to the needs of a specific region. This analysis aims at evaluating the performance of a finite difference-based numerical model (MODFLOW-ΜΤ3DMS), a finite element-based numerical model (FEFLOW), and a hybrid finite element-finite difference coupling numerical model (Princeton Transport Code-PTC), all developed to simulate groundwater flow and nitrate mass transport in an alluvial aquifer. The evaluation of the models’ performance is assessed based on statistical measures and graphical performance analysis of the model point predictions to the observed values. The outcome of the analysis showed that among the three groundwater simulation models, FEFLOW algorithm exhibited the best performance in simulating both groundwater level and nitrate mass distribution. All simulation algorithms were found to offer different advantages, so in principle the selection of the appropriate model(s) should be done in accordance with the problem’s characteristics and/ or in a complementary way in order to achieve accurate representation of the aquifer system and thus optimal groundwater resources management. Even though the selection of the most suitable groundwater simulation algorithm is case-oriented, however, fractional gross error (FGE) was proven to be a reliable indicator that could be used by modelers to select the most suitable groundwater algorithm based on the available groundwater data. © 2019, Springer Nature Switzerland AG

Multivariate statistical analysis of the hydrogeochemical and isotopic composition of the groundwater resources in northeastern Peloponnesus (Greece)

The present study involves an integration of the hydrogeological, hydrochemical and isotopic (both stable and radiogenic) data of the groundwater samples taken from aquifers occurring in the region of northeastern Peloponnesus. Special emphasis has been given to health-related ions and isotopes in relation to the WHO and USEPA guidelines, to highlight the concentrations of compounds (e.g., As and Ba) exceeding the drinking water thresholds. Multivariate statistical analyses, i.e. two principal component analyses (PCA) and one discriminant analysis (DA), combined with conventional hydrochemical methodologies, were applied, with the aim to interpret the spatial variations in the groundwater quality and to identify the main hydrogeochemical factors and human activities responsible for the high ion concentrations and isotopic content in the groundwater analysed. The first PCA resulted in a three component model, which explained approximately 82% of the total variance of the data sets and enabled the identification of the hydrogeological processes responsible for the isotopic content i.e., δ18Ο, tritium and 222Rn. The second PCA, involving the trace element presence in the water samples, revealed a four component model, which explained approximately 89% of the total variance of the data sets, giving more insight into the geochemical and anthropogenic controls on the groundwater composition (e.g., water-rock interaction, hydrothermal activity and agricultural activities). Using discriminant analysis, a four parameter (δ18O, (Ca+Mg)/(HCO3+SO4), EC and Cl) discriminant function concerning the 222Rn content was derived, which favoured a classification of the samples according to the concentration of 222Rn as 222Rn-safe (<11Bq·L-1) and 222Rn-contaminated (>11Bq·L-1). The selection of radon builds on the fact that this radiogenic isotope has been generally related to increased health risk when consumed. © 2014 Elsevier B.V

Nutrient dynamics in temperate European catchments of different land use under changing climate

Study region: Vltava River basin, South Bohemian Region of the Czech Republic, Central Europe Study focus: To understand the dynamics of nutrients (nitrogen, phosphorus, and organic carbon) in streams, we combined hydrometeorological, hydrochemical and isotopic data (stable water and nitrate isotopes) from three catchments with different predominant land-use effects (forest, agricultural and settlement). New hydrological insights for the study region: Our study underlines that current climate change and associated hydrological changes, such as decrease in flow, play an important role in the transport and dynamics of nutrients in the catchment. We have found that due to the different origins and pathways, individual nutrients had diverse behaviour patterns in streams and responded differently to changing climate. Hydrological patterns in streams became clear when systematic and continuous monitoring under a changing climate was applied, highlighting the need for such data to better understand the impact of hydrological drivers, particularly for long-term dynamics. In three studied catchments, streamflow showed a decreasing trend in line with rising air temperature, declining snow cover and increasing evapotranspiration. Time series analyses of nitrate concentrations revealed decreasing trends, whereas dissolved organic carbon increased in all catchments regardless of land use. Long-term trends of total phosphorus concentrations were positive in anthropogenically impacted streams. Stable nitrate isotopes indicated distinct nitrate sources and processes, but also their seasonality in relation to hydrological patterns and land use