Nation's Ground-water Resources Research Articles

Using L. minor and C. elegans to assess the ecotoxicity of real-life contaminated soil samples and their remediation by clay- and carbon-based sorbents

Toxic substances, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, can accumulate in soil, posing a risk to human health and the environment. To reduce the risk of exposure, rapid identification and remediation of potentially hazardous soils is necessary. Adsorption of contaminants by activated carbons and clay materials is commonly utilized to decrease the bioavailability of chemicals in soil and environmental toxicity in vitro, and this study aims to determine their efficacy in real-life soil samples. Two ecotoxicological models (Lemna minor and Caenorhabditis elegans) were used to test residential soil samples, known to contain an average of 5.3, 262, and 9.6 ppm of PAHs, lead, and mercury, for potential toxicity. Toxicity testing of these soils indicated that 86% and 58% of soils caused ≤50% inhibition of growth and survival of L. minor and C. elegans, respectively. Importantly, 3 soil samples caused ≥90% inhibition of growth in both models, and the toxicity was positively correlated with levels of heavy metals. These toxic soil samples were prioritized for remediation using activated carbon and SM-Tyrosine sorbents, which have been shown to immobilize PAHs and heavy metals, respectively. The inclusion of low levels of SM-Tyrosine protected the growth and survival of L. minor and C. elegans by 83% and 78%, respectively from the polluted soil samples while activated carbon offered no significant protection. These results also indicated that heavy metals were the driver of toxicity in the samples. Results from this study demonstrate that adsorption technologies are effective strategies for remediating complex, real-life soil samples contaminated with hazardous pollutants and protecting natural soil and groundwater resources and habitats. The results highlight the applicability of these ecotoxicological models as rapid screening tools for monitoring soil quality and verifying the efficacy of remediation practices.

Инфилтрационно подхранване и ресурси на подземните води в басейна на р. Тунджа, ЮИ България

This article presents the assessment results of the long-term annual average groundwater recharge for the territory of the Tundzha River catchment area. In order to assess those results, a GIS-method has been applied based on spatial analysis of the slope of the relief, soil cover and aquifer properties. A series of maps is presented and a quantitative analysis of the results obtained is carried out. The mean annual groundwater recharge ranges from 4 to 483 mm, or about 55 mm on average for the catchment area. Additional calculations have been made for water management purposes. For individual groundwater bodies that fall into the catchment area of the Tundzha River (managed primarily by the East Aegean River Basin Directorate) both groundwater recharge and their natural groundwater resources were assessed (based on the outcrop areas of the respective bodies).

Spatiotemporal deep learning approach for estimating water content profiles in soil layers

Land subsidence associated with using natural groundwater resources for serving the growing population needs has been receiving extensive research attention in the literature over the past few decades. The water content fluctuation in the of subsurface soil layers significantly impacts the land subsidence. The key objective of this study is to predict changes in water content profiles in soil layers over a long period of time using a deep learning-based approach. A convolution neural network algorithm that is commonly used in Artificial Intelligence (AI) applications is modified in the present study for processing in-situ measurement water content profiles. The approach used in the proposed AI method has a distinct advantage for generating dynamic predictions based on the extracted spatiotemporal characteristics of the data. In addition, three different algorithms are compared with respect to time series prediction, including long-short-term memory (LSTM), multiple-layer perceptron (MLP) networks and autoregressive integrated moving average (ARIMA).

QUANTITY AND QUALITY OF GROUNDWATER OF INTERMOUNTAIN BASIN OF KORÇA IN ALBANIA AND IMPLICATION FOR SUSTAINABLE MANAGEMENT

Korça intermountain basin is the largest of its kind in Albania and from the hydrogeological point of view represents a semiclosed intermountain basin developed in Pliocene-Holocene granular unconsolidated deposits, which maximal thickness is about 300 m. The aquifer consists of intergranular gravelly to sandy layers containing artesian groundwater and the drilling wells are free flowing on most of the basin surface. The main recharge of the intergranular aquifer comes mainly from the rivers and torrents flowing from mountain gorges around the Korça Plain. The natural groundwater drainage of Korça basin is realized through the vertical leakage in the area of the former Maliq marsh. Hydrochemistry of the aquifers show the presence of four main hydrochemical facies which are related mainly to the hydrochemistry of the recharge sources and to the solution processes and ion exchange. In the central part of the basin the water supply wells of the cities Korça and Maliq are located. The natural renewable groundwater resources of the basin are relatively restricted, but the volume resources (or static water resources) are abundant (about 1.1 × 10–9 m3). The perspective of their exploitation is very important, but respecting the “basin yield” concept that is defined as the maximum rate of withdrawal that can be sustained by the hydrogeological system of groundwater basin without causing unacceptable changes to any other environmental component of the basin. To face the problems related to the intensification of the groundwater pumping systematic observations of the hydraulic reaction of the basin and of the possible groundwater quality deterioration and other negative environmental impacts must be organized. The purpose of the present study is for the first time to analyze the abundant basin wide hydrogeological data and to evaluate: (1) geometry and hydraulic parameters of the aquifers: (2) groundwater hydrodynamic conditions; (3) their chemical composition and (4) the natural groundwater resources and the possibility to intensify the groundwater pumping in close relation to the environmental impact.

NUMERICAL MODELING OF THE RELATIONSHIP BETWEEN GROUND AND SURFACE WATERS (ON THE EXAMPLE OF THE NOVODVORSKOYE BASALT DEPOSIT)

A new methodological approach to the computational assessment of the interconnection between soils and water pollution is proposed, which consists in a set of digital relief maps and a hydrographic network for compiling hydroisogypse maps and infiltration coefficients of groundwater recharge. A brief description of the numerical geofiltration model of groundwater of the Novodvorskoye deposit of basalts and accompanying tuffs is given. The technology of implementation on the model of surface reservoirs and watercourses is presented. Within the simulated area, the natural resources of groundwater are estimated, the value of which is divided into groundwater runoff into rivers and groundwater discharge by evaporation. Based on the results of modeling the natural filtration of groundwater, the structure of the balance of groundwater and surface water was assessed, maps of hydroisohypses, depths of occurrence and intensity of infiltration recharge of groundwater were constructed.

Estimation of natural groundwater resources in hydrogeological zones in the Czech Republic under changing climatic conditions 1981–2019

V České republice (dále ČR) v rámci regionálního hydrogeologického průzkumu byly už v roce 1965 vymezeny hydrogeologické rajony. Hydrogeologický rajon (HGR) je definován jako celek s obdobnými hydrogeologickými poměry, vymezený tektonicky a geologicky, na jehož území převládá určitý typ zvodnění a oběhu podzemní vody. V několika časových etapách byly hranice HGR upravovány a postupně byly různými postupy určovány jejich číselné hydrogeologické charakteristiky, z nichž jedním ze základních údajů je velikost přírodních zdrojů podzemní vody. Přírodní zdroje jsou dynamickou složkou podzemních vod a vyjadřují se v m3.s-1. Přírodní zdroje jsou dány dotací vody do zvodněného systému (srážky, přetoky podzemní vody z jiných kolektorů, přirozená infiltrace povrchové vody apod.). Pokud je HGR hydrogeologicky uzavřený, lze dlouhodobý průměr jeho dotace ze srážek i dlouhodobý průměr základního odtoku použít jako odhad přírodního zdroje podzemních vod. V rámci projektu „Rebilance zásob podzemních vod“ byly zpracovány odhady přírodních zdrojů podzemní vody ve 152 hydrogeologických rajonech v ČR, které jsou uvedeny ve zprávě [1]. Přírodní zdroje byly stanoveny několika odlišnými postupy s využitím dat z období 1971–2010, případně 2000–2010.

КАРТОГРАФИРОВАНИЕ НАЛЕДЕЙ В ТРАНСГРАНИЧНОМ БАССЕЙНЕ Р. ЧИКОЙ

The basin of the transboundary Chikoy River is the largest in terms of area among the catchment areas of the main tributaries of the Selenga River. The Selenga basin as a whole is characterized by a wide distribution of icing. The paper presents the results of mapping icings and their distribution according to various physical and geographical characteristics. Based on the Landsat-8 satellite imagery for 2019, a cartographic database of icings was compiled for the first time for this territory. The database includes 6,319 objects on a total area of 140 km2. The largest icing is 671.13 thousand m2 in area. The mean value, median, and mode are 22.16, 12.86, and 10.24 thousand m2, respectively. Most of the icings are located at altitudes of 900–1,200 m and on the slopes of the eastern exposure. Icings were not found in the western part of the Chikoy River basin and in the near-top belt of the ridges. Fissure rocks are predominant in the study area, which indicates the leading role of groundwater in the formation of icing. The greatest icing coverage is found in areas with annual precipitation in the range of 350–460 mm and with an average annual temperature of –2.5 ... –3℃. In the landscape structure, icing is common in low- and mid-mountain taiga larch-dark coniferous landscapes. About 80% of the icings are located on the complexes of soddy podburs, podburs, soddy podzols, and other associated soils. The level of icing coverage was found to be not proportional to the natural resources of groundwater, which can be caused by both the imperfection of the original groundwater map and the uncharacteristic manifestation of icing in 2019. The resulting database will become the basis for retrospective and predictive assessments of the icing dynamics in the Chikoy and Selenga River basins.

Features of spring waters of steppe regions (on the example of the city of Rostov-on-Don)

The springs of the city of Rostov-on-Don in the Rostov region have been investigated. It is an arid climatic zone characterized by limited natural resources of fresh groundwater. There are more than 60 springs in the city. In terms of chemical composition, water is characterized by increased hardness. An aesthetic assessment of the city’s springs was carried out. Three categories of springs are identified, their specialization and features of use and pollution are analyzed. Indicators have been obtained that can be used to regulate the ecological and aesthetic value of the landscape approach in the areas where the springs are located. This creates an opportunity to improve the springs and create new resting places on their basis. Work to increase the recreational value should be carried out for each source separately, after preliminary, thorough work on the study of the terrain, landscape approaches, so as not to cause irreparable harm to nature.

СОВРЕМЕННОЕ СОСТОЯНИЕ РЕСУРСНОГО ПОТЕНЦИАЛА ПРЕСНЫХ ПОДЗЕМНЫХ ВОД ХАНТЫ-МАНСИЙСКОГО АВТОНОМНОГО ОКРУГА

This article examines the resource potential and modern extraction of fresh groundwater for the needs of population and economic sectors in the Khanty-Mansi Autonomous Okrug – Yugra. The history of regional hydrogeological studies on the assessment of natural resources and exploitation reserves of groundwater reserves of the West Siberian mega-basin (WSMB) is revealed. The research results are shown and their comparative analysis is carried out. The article highlights the issue of formation and distribution of natural resources over the area of the considered territory. In conclusion, it is noted that the territory of the Khanty-Mansi Autonomous Okrug – Yugra is sufficiently supplied with natural resources of fresh groundwater (the predicted useful groundwater resources supply is 66.86 m3/day per person). However, more than 20 years have passed since the implementation of regional works on the assessment of predicted groundwater resources in the territory of the Khanty-Mansi Autonomous Okrug. During this period, the water-economic situation in the region has changed significantly, a large amount of factual material, which makes it possible to clarify and probably to revise the previously obtained results has been accumulated.

Groundwater vulnerability mapping using the modified DRASTIC model: the metaheuristic algorithm approach.

Vulnerability assessment and mapping is a significant tool for sustainable management of the precious natural groundwater resources. DRASTIC is an extensively used index model to map groundwater vulnerable zones. However, the original DRASTIC model rates and weights used in most of the research depict the poor correlation between nitrate concentration and groundwater vulnerability index. Wilcoxon test and five population-based metaheuristic (MH) algorithms, namely, firefly algorithm (FA), invasive weed optimization (IWO), teaching learning-based optimization (TLBO), shuffled frog leaping algorithm (SFLA), and particle swarm optimization (PSO), were used to optimize the rates and weights of the DRASTIC model to improve its accuracy. The performance of all the employed metaheuristic algorithms converges to a global optimal solution at different iterations, and to choose the best algorithm for DRASTIC weights optimization, a ranking methodology was proposed. The algorithms were ranked by calculating the relative closeness of alternatives with computational speed and the number of iterations as attributes in the TOPSIS method.This study identifies FA as the outperforming algorithm among the employed for this specified weight optimization problem based on ranking. The result of the optimization model proposed depicts significant improvement in the correlation coefficient between the groundwater vulnerability index and nitrate concentration from 0.0545 for the original DRASTIC model to 0.7247 for the Wilcoxon-MH- DRASTIC. Hence, this ranking approach can be adopted when global optimal solution is found by all employed algorithms in DRASTIC weight optimization.

Evaluation of water saving technologies at Estidamah research center in Saudi Arabia

Water saving is crucial for the survival of agriculture in Saudi Arabia. Natural ground water resources are depleting by the extensive water use for agriculture. At the Estidamah research center in Riyadh water saving technologies for protected horticulture are evaluated in the harsh climatic conditions. Different levels of technology, viz., low, mid and high-tech were evaluated based on water use, energy consumption and production. The low-tech greenhouse is a plastic tunnel greenhouse cooled using a pad and fan system. This type of greenhouse is normally used for year-round production. The mid-tech greenhouse has a glass covering and is also cooled using the pad and fan system though here the amount of ventilation can be regulated using frequency-controlled fans. Finally, the high-tech greenhouse was considered which is a closed greenhouse. The cooling and dehumidification were done using coolers. The center is now in operation for more than two years so the water use over the year for the various types of greenhouse technologies can be evaluated. The water use for cooling in the mid-tech greenhouse is 30% less than what is used in the low-tech greenhouses. The water saving in the high-tech greenhouse is more than 95%.

Geoinformation technologies and methods of mathematical modeling in hydrogeological research

In the article the application issues of geographic information technologies and methods of mathematical modeling of geofiltration and geomigration processes of hydrogeological systems were discussed, as well as for information support of the groundwater monitoring system. The object of research is the Akhangaran aquifer, which is a large industrial area with intensification of agriculture, as well as densely populated, where industrial reproduction of water resources is established by designing water intake facilities using groundwater, also having huge data on regime, geological and hydrogeological aspects. The main goal of these researches is to learn the methodology for assessing groundwater resources by modeling to the GIS basis, theoretical and applied methods of mathematical analyses. The features are considered and the boundary and initial conditions are justified. The results are a research technique has been developed to simulate geofiltration and geomigration processes, to determine the balance of groundwater, and the hydrogeological parameters of the aquifer have been calculated from it. The calculated values of the natural resources of groundwater by the parameters of their level mode in the Akhangaran pool allowed establish the permissible convergence of resource estimates according to the amplitudes of fluctuations in the level of groundwater and according to geoinformation modeling.

Determination of the groundwater recharge in the Blagoevgrad valley Neogene sediments

A comprehensive approach to determine the natural groundwater recharge in the Blagoevgrad valley Neogene sediments is presented. It involves the application of various methods such as the balance method, hydrodynamic modeling in GIS, the FeFlow numerical model, the Döll et al. empirical method. The obtained results show good similarity between different methods, including the long-term groundwater recharge for the study area calculated by rainfall infiltration. Therefore, the complex approach used gives an accurate estimate of the groundwater recharge in the Blagoevgrad valley associated with Neogene sediments. It can be successfully applied to determine the natural groundwater resources for other similar groundwater bodies. In this way, the groundwater resource assessments, management and conservation in Bulgaria can be significantly improved.

A retrospective analysis of the impact of climate change on groundwater resources

Based on the actual meteorological data that characterize statistically significant changes in the air temperature and the amount of precipitation in the southwest of the Moscow artesian basin, the conditions that form the water balance and groundwater recharge are modeled. The comparison of the calculated longterm average values for the previous (1965–1988) and recent (1989–2012) periods made it possible to estimate the climate changes in the elements of water balance and groundwater recharge. Based on the maps of longterm average groundwater recharge for these periods, which were constructed using the results of modeling, the estimation of the change in natural resources of groundwater in the territory was performed, showing an increase of 9% (780000 m3/day).

Risk assessment of groundwater pollution with a new methodological framework: application of Dempster–Shafer theory and GIS

Managing natural groundwater resources is challenged by nitrate pollution resulting from agricultural activities. This issue is emerging as an important environmental concern that needs to be addressed through effective groundwater management. Groundwater assessment is an important aspect of groundwater management, particularly in arid and semi-arid regions. This study focused on the Kerman Plain, which is exposed to intensive agricultural activities and land exploitation that result in intense land pollution. The effects of nitrate pollution may be controlled by applying specific measures. Dempster–Shafer theory (DST) was applied in this study to develop a new methodology for assessing pollution risk. Applying this theory as a pioneering approach to assessing groundwater pollution risk is the novel component of this research. This approach provides a major advantage by dealing with varying levels of precision related to information. The spatial association between DRASTIC parameters including D (depth of water), R (net recharge), A (aquifer media), S (soil media), T (topography), I (impact of vadose zone) and C (hydraulic conductivity) and underground nitrate occurrence was evaluated by applying bivariate DST to assign mass functions. Dempster’s rule of combination using GIS was then applied to determine a series of combined mass functions for multiple hydrogeological data layers. The uncertainty of system responses was directly addressed by the proposed methodology. Finally, the modified DRASTIC map with the highest validity and accuracy was selected and combined with the damage map. The comparison between nitrate distribution and vulnerability and the risk maps exhibit high similarity between different vulnerability degrees and nitrate concentrations. Long-term planning of preventive measures and associated developments can be aided by the regions with low and very low risks located in the northeast, northwest, and central regions.

Potential pollution risk in natural environment of golf courses: an example from Rusovce (Slovakia)

The objective of the article presented herein is to highlight the specific issue of the protection of water sources in the vicinity of golf courses. Currently we have experienced the construction of a large number of golf courses, which are often found in areas where the protection of natural groundwater resources is needed. In this article, limit conditions are specified, which could be used in construction of other golf courses in the world, where there is a potential threat of contamination of groundwater resources. The issue is demonstrated on a case study in the area of a water resource, Rusovce. A major concern of golf courses is the fact that in an apparently clean environment of these anthropogenic structures contamination occurs, resulting from the maintenance, and the current legislation does not address this specific group of areas. These are particularly dangerous substances derived from fertilizer and turf protection, in particular the use of pesticides (insecticides, herbicides, fungicides, acaricides, e.g. nematocides, and related products, such as growth regulators used for plant protection). The results of the modelling at the water source, Rusovce, show that the combination of negative factors (for example, the groundwater table level close to the surface along with extremely high precipitation totals or the areas flooding and the lack of a golf course bedrock sealing) the limit value of 0.100 μg/l of pesticides concentration in groundwater was exceeded up to 0.880 μg/l. Similarly, such excess may occur in the case of an emergency situation (for example, the spilling of the barrel with the pesticide), where the concentration of pesticides in groundwater may be increased up to 0.874 μg/l in standard conditions (without flooding with an average depth of groundwater table level beneath the terrain). But even under a standard level of security for the establishment and operation of a golf course and standard procedures for the maintenance of the lawn, the concentration of pesticides in the wells reached 0.0001 μg/l.

A system dynamics approach for water resources policy analysis in arid land: a model for Manas River Basin

The Manas River Basin in Xinjiang Uygur autonomous region, similar to other arid regions, is facing water constraints which challenge decision-makers as to how to rationally allocate the available water resources to meet the demands from industries and natural ecosystems. Policies which integrate the supply and demand are needed to address the water stress issues. An object-oriented system dynamics model was developed to capture the interrelationships between water availability and increasing water demands from the growth of industries, agricultural production and the population through modeling the decision-making process of the water exploration explicitly, in which water stress is used as a major indicator. The model is composed of four sectors: 1) natural surface and groundwater resources; 2) water demand; 3) the water exploitation process, including the decision to build reservoirs, canals and pumps; 4) water stress to which political and social systems respond through increasing the supply, limiting the growth or improving the water use efficiency. The model was calibrated using data from 1949 to 2009 for population growth, irrigated land area, industry output, perceived water stress, groundwater resources availability and the drying-out process of Manas River; and simulations were carried out from 2010 to 2050 on an annual time step. The comparison of results from calibration and observation showed that the model corresponds to observed behavior, and the simulated values fit the observed data and trends accurately. Sensitivity analysis showed that the model is robust to changes in model parameters related to population growth, land reclamation, pumping capacity and capital contribution to industry development capacity. Six scenarios were designed to investigate the effectiveness of policy options in the area of reservoir relocation, urban water recycling, water demand control and groundwater pumping control. The simulation runs demonstrated that the technical solutions for improving water availability and water use efficiency are not sustainable. Acknowledging the carrying capacity of water resources and eliminating a growth-orientated value system are crucial for the sustainability of the Manas River Basin.

Current changes in water resources in Lena River basin

The effect of climate on the present-day formation conditions of the regimes of annual and base runoff in Eastern Siberia rivers and changes in those regimes are studied. The significant climate warming in Eastern Siberia in recent decades is shown to be accompanied by not only an increase in air temperature and some increase in precipitation, but also by a considerable changes in the annual and seasonal values of river and groundwater runoff. Hydrometeorological data are used to analyze variations in the mean annual and mean base runoff over the entire observation period divided into subperiods of 1940–1969 and 1970–2005. Plots, diagrams, and tables are constructed for the most representative gauges. The zoning of the territory by the runoff formation conditions was carried out and new estimates were derived for total water resources and natural groundwater resources for 1970–2005 with the construction of maps in ArcMap program.

Tracing the source of bottled water using stable isotope techniques

The Indian Summer Monsoon (ISM) precipitation recharges ground water aquifers in a large portion of the Indian subcontinent. Monsoonal precipitation over the Indian region brings moisture from the Arabian Sea and the Bay of Bengal (BoB). A large difference in the salinity of these two reservoirs, owing to the large amount of freshwater discharge from the continental rivers in the case of the BoB and dominating evaporation processes over the Arabian Sea region, allows us to distinguish the isotopic signatures in water originating in these two water bodies. Most bottled water manufacturers exploit the natural resources of groundwater, replenished by the monsoonal precipitation, for bottling purposes. The work presented here relates the isotopic ratios of bottled water to latitude, moisture source and seasonality in precipitation isotope ratios. We investigated the impact of the above factors on the isotopic composition of bottled water. The result shows a strong relationship between isotope ratios in precipitation (obtained from the GNIP data base)/bottled water with latitude. The approach can be used to predict the latitude at which the bottled water was manufactured. The paper provides two alternative approaches to address the site prediction. The limitations of this approach in identifying source locations and the uncertainty in latitude estimations are discussed. Furthermore, the method provided here can also be used as an important forensic tool for exploring the source location of bottled water from other regions.

Climate-induced changes in groundwater runoff in Don basin

The natural-climatic causes of changes in river runoff and seasonal recharge of groundwater in Don basin are considered. Joint analysis is made of changes in the statistical characteristics of the series of air temperature and precipitation, mean annual and dry-season-averaged runoff for both the entire observation period and of periods 1940–1969 and 1970–2000 with comparable durations. The presence of statistically reliable ascending trends in air temperature, precipitation, and dry-season (groundwater) runoff for period 1970–2005 is demonstrated. Climatic changes in Don basin also have their effect on the formation of extremely low water in small and medium rivers, including cases of zero runoff. Zoning of the territory by runoff formation conditions is carried out, and new estimates of natural groundwater resources in Don basin for period 1970–2000 are constructed. Appropriate maps are compiled.