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The increasing number of visitors and conflicts resulting from shared use in valorising sensitive wetlands make effective visitor and site management measures essential. In the course of this research, the landscape pattern, the current spatial distribution of tourist activities and the possible arrangement of expedient further development were examined. The study area, Lake Tisza, is an artificial lowland reservoir established in the 1970s with an area of 127 km2 in Hungary. Among its original functions, in addition to flood control, nature conservation and recreation have become the main profiles. The diverse hydro-ecological features and mosaic landscape structure allow for nature conservation and utilisation in tourism. This differentiated use is in line with the worldwide trend of favouring locations with multiple leisure activities in close proximity to each other. Based on the CORINE Land Cover (CLC) 2018 database, 12 different land use categories were identified in the study area. The largest proportion is represented by water bodies (53.29%), while inland marshes and broad-leaved forests cover 22.25% and 16.64%, respectively. The heterogeneity of the area is considerably enhanced by the high patch sizes of the categories pastures, broad-leaved forests and inland marshes. According to the Shannon diversity index, the most complex landscape diversity can be found in the Tiszavalk (1.5) and Poroszló (1.4) basins, considered to be the most suitable for ecotourism, while the lower values of the Sarud (1.1) and Abadszalók (1.1) basins provide suitable conditions for water sport activities and recreational tourism. Continuous adaptation to social needs and the joint protection of natural values is crucial for the sustainable development of Lake Tisza.

In this research, contamination levels and the spatial pattern identification, as well as human and environmental health risk assessments of the heavy metals in the phreatic groundwater aquifer of the Oued Souf Valley were investigated for the first time. The applied methodology comprised a combination of heavy-metal pollution indices, inverse distance weighting, and human health risk assessment through water ingestion on samples collected from (14) monitoring wells. The contamination trend in the phreatic aquifer showed Al > B > Sr > Mn > Fe > Pb > Ni > Cr > Ba > Cu > Zn. Similarly, the enrichment trend was Al > B > Sr > Mn > Ni > Pb > Cr > Ba > Cu > Zn. Ecologically, most of the analyzed metals reflected a low potential ecological risk, except for two wells, S13 and S14, which represented a considerable and high ecological risk in terms of Pb. According to the applied grouping method, the samples in the first group indicated a lower risk of contamination in terms of heavy metals due to their lower concentration compared to the second group. This makes the area containing the second group’s samples more vulnerable in terms of heavy metals, which could affect urban, preurban, and even agricultural areas. All of the samples (100%) indicated the possibility of potential health risks in the case of children. While six samples showed that the non-cancer toxicity risk is considered low, the rest of the samples had high Hazard Index (HI) values, indicating the possibility of health risks occurring in the case of adults. The constructed vertical drainage system is acting as a supporter and accelerator of the pollution levels in the shallow groundwater aquifer. This is due to its contribution to the penetration of different pollutants into this aquifer system, depending on the residence time of the water, which appears to be long within the drainage system.

Outdoor recreation has grown rapidly in recent years, with an increasing preference for areas in good ecological condition. Since lakes represent some of the most important wetlands, providing a wide variety of ecosystem services, they have become a very popular destination. The present study aimed to assess the water quality of the largest artificial lake in Hungary (Kisköre Reservoir—Lake Tisza), and the role of ecological status in tourism development. Monthly water sampling from the basins of the lake (Tiszavalk, Poroszló, Sarud and Abádszalók basins) took place from April–November 2021 and in 2022. The majority of samples from the river section and from the lake are classified as Ca2+-HCO3− type or mixed Ca2+-Na+-HCO3− type. According to the results, the water quality of each basin is considered excellent or good. Rapid warming of the shallow water of the basins was detected during the summer months, resulting in different hydrochemical characteristics (pH, NH4-N, NO2-N, NO3-N, PO4-P, CODcr BOI5) compared to the river section. Differences in the plant nutrient and oxygen balance component groups have been revealed with hierarchical and two-step cluster analysis as well. The results demonstrated that the hydrochemical properties of the lake’s water are substantially influenced by the filling of the lake in spring from the River Tisza and the significant lowering (1.2 m) of the water level in the autumn each year, allowing the drainage of stagnant water, the removal of accumulated sediments and the oxidation of organic matter. The number of tourists on Lake Tisza has increased rapidly over the last decade, confirming that a wide range of ecosystem services have a significant attractive impact on waterfront activities and ecotourism.

Septic tanks without proper construction and insulation entail a significant risk to the environment. In this study, the environmental impacts of a permeably designed septic tank on shallow groundwater contamination are investigated, and changes in water quality in the period after its elimination in 2014 are assessed. For the purpose of evaluating the pollution level of the site, 10 monitoring wells were installed around the septic tank in 2012 and long-term monitoring was carried out. Analytical measurements revealed a significant level of groundwater contamination in the operational period of the septic tank. Extremely high concentrations of NH4+ (>90 mg/L) were observed in the closest monitoring wells, and in most of the wells, concentrations exceeded the relevant contamination limit. δD and δ18O isotopic ratios of monitoring wells within 1 m from the septic tank indicate continuous recharge of sewage water originating from deeper aquifers. The groundwater dome resulting from the wastewater discharge exceeded 1.1 m, within a distance of 25 m. Statistical analyses also revealed significant changes in water quality depending on the monitoring well location from the septic tank. In the period after the septic tank elimination, considerable changes have been detected. Following the cessation of the wastewater discharge, the groundwater dome around the septic tank disappeared; therefore, differences in groundwater levels have decreased from more than 1 m to a few cm. Significant positive changes were detected in the water quality parameters investigated after the dismantling of the septic tank. Five years after the cessation of the pollutant supply, concentrations still exceeded the contamination limit in most of the monitoring wells, indicating slow decontamination processes with a permanently high level of pollution.

Since the beginning of the 1980s, several regions in the northern Sahara of Algeria have been confronting the rising groundwater. Among all these regions, Oued Souf Valley represented one of the most acute affected by this phenomenon. Due to the natural topography and the insufficient/weakness of water management and miscoordination between different sectors that are represented by intensive exploitation of deep groundwater reservoirs which returns to the shallow aquifer, absence of sewage and drainage network, leakage from drinking water supply system, the groundwater has raised to the surface or near to the surface, affecting the traditional cultural environment and urban areas and degrading all socio-economic aspects of the Oued Souf habitants. To preserve the Oued Souf environment, a vertical drainage system has been constructed. Consequently, in this research, an evaluation of the vertical drainage system performance and its impact on groundwater level stabilization has been performed by mapping the water table of the phreatic groundwater level using geostatistical modeling using ordinary kriging (OK) interpolation method, which has been applied to analyze the spatial and temporal structure of groundwater level fluctuation. Meanwhile, hierarchical cluster analysis (HCA) was applied for grouping the wells based on the groundwater fluctuations for 2008, 2009, 2014, 2016, 2018, and 2021. However, the vertical drainage system reflected a significant decline of groundwater from 2009 to 2018 due to the important drained volumes through it but another rising phenomenon might be threatening the region in the near future and this is what was indicated in the 2021 groundwater level data. Cluster analysis has generated four groups based on their fluctuation means that are increasing from the first group to the fourth group ascendingly. The first cluster grouped the drains that have a shallow depth (average mean of 5.91 mbgl) and declined over the clusters. The clusters are spatially combined with significant separation of the fourth cluster which represents the deepest group (12.89 mbgl). Based on this research, several factors are influencing the stability of the phreatic groundwater level and even the performance of the drainage system, the most important of which is the overexploitation from deep groundwater reservoirs such as complex terminal and continental intercalary (in drinking and irrigation) and even the illegal use of the phreatic groundwater with important quantities for irrigation and illegal industries.

The provision of webGIS-based water quality data services has become a priority area for both the public and administrative sectors in the context of the pandemic emergency associated with the global spread of COVID-19. Current geographic, monitoring and decision supporting systems, typically based on web-based geospatial information, greatly facilitate the sharing of spatial and temporal data from environmental databases and real-time analyses. In the present study, different water quality indices are determined, compared and geovisualized, during which the changes in the quality of the shallow groundwater resources of a settlement are examined in the period (2011–2019) in an eastern Hungarian settlement. Another objective of the research is to determine three water quality indices (Water Quality Index, CCME Water Quality Index, Contamination degree) and categorize water samples based on the same input spatial and temporal data using self-developed freely available geovisualization tools. Groundwater quality was assessed by using different water quality indices. Significant pollution of the groundwater in the time period before the installation of a sewage network was shown. Regarding water quality, significant positive changes were shown based on all three water quality indices in the years after installing a sewage network (2015–2019). The presence of pollution apart from the positive changes suggests that the purification processes will last for a long time.

Disposal sites without adequate engineering controls pose a significant risk to the environment. In the present study, the environmental hazards of an abandoned and unrecultivated liquid waste disposal are investigated with a special focus on soil and shallow groundwater contamination. After a period of operation from 1994 to 2010, when the wastewater collection of the municipality was regulated, the disposal site was subsequently decommissioned without further action. Eight monitoring wells have been established in the disposal basins and in the surrounding area to determine the contamination of the site. Sampling took place in the summers of 2020 and 2021. The results of the analysis of the soil and water samples collected showed a high level of contamination in the area. In the borehole profile of the infiltration basin, a well-developed leachate nitrate profile was observed, with a concentration above 3000 mg/kg NO3−. The soil phosphate content was also significant, with a value of over 1900 mg/kg in the upper 40 cm layer. Extremely high concentrations of ammonium (>45 mg/L) and organic matter (>90 mg/L) were detected in the groundwater of the basins, indicating that contaminated soil remains a major source of pollutants more than 10 years after closure. For all micro- and macroelements present in detectable concentrations, a significant increase was observed in the infiltration basin. Our results have revealed that the surroundings are also heavily contaminated. NO3− concentrations above the contamination limit were measured outside the basins. Recultivation of liquid waste disposal sites of similar characteristics is therefore strongly recommended.

In the present study, the impact of the construction of the sewerage network (2014) on groundwater quality was studied on the example of a middle-sized settlement in the Great Hungarian Plain and changes in water quality were assessed using GIS and multivariate statistical analysis. As a result of the pollution that has been going on for decades, the groundwater supply of the municipality has become heavily polluted. In the period before sewerage (2011–2013), clear spatial differences were shown in the degree of contamination in the area of the settlement: the degree of contamination increased in the direction of local groundwater flow. Based on our results, the construction of the sewerage network resulted in marked changes in the quality of groundwater wells. Our studies showed a clear decrease in the concentrations of inorganic pollutants (NH4+, NO2−, NO3−, PO43−). In the fifth year of the post-sewerage period (2019), the clear spatial difference between wells was eliminated. We have observed a strong descent (1.5 to 2 m) in groundwater levels in the post-sewerage period, the reason for that is clearly due to that wastewater outflow was eliminated. On this basis, it can be declared that the purification processes in the area have started, but at the same time, our results show that pollutants entering environment undergo a number of transformations and remain in the system for a long time.

This research aims to assess the hydrogeochemical evolution of the groundwater in Oued souf valley for drinking and irrigation purposes. To achieve this, 49 groundwater samples from the complex terminal were examined and treated concurrently with multivariate statistical methods, geostatistical modeling and the WQI (water quality index). Focusing on the physico-chemical parameters, Q mode clustering analysis detected four major water groups, where the mineralization augmented from group 1 to group 4. The hydro-chemical type was the same, Ca-Mg-Cl-SO4 for all the groups. Calcite, dolomite, anhydrite, and gypsum would be the dominant reactions with the undersaturation of evaporates minerals, based on geochemical modeling, while the carbonate minerals are precipitating. Geostatistical analysis using ordinary Kriging demonstrated the exponential semi-variogram model fitted for EC (electrical conductivity), Ca2+ (calcium), Mg2+ (magnesium), K+ (potassium), HCO3− (bicarbonate), Cl− (chloride), and SO42− (sulfate). At the same time, the rational quadratic model was the best-fitted semi-variogram model for Na+ (sodium) and NO3− (nitrate). EC, SO42−, and NO3− have a strong spatial structure, while Ca2+, Na+, K+, and HCO3− have a moderate spatial structure. Moreover, there was a weak spatial structure for Mg2+ and Cl−. The WQI shows that CT (complex terminal groundwater aquifers) are not suitable for drinking and their quality for irrigation fluctuates from excellent to moderate quality.

The appearance of online map services and frameworks (e.g., KML, QGIS) has increased the possibilities to easily, quickly and—in many cases—cost-effectively publish spatial data stored in databases. The aim of this study is to present the geovisualization of spatial databases of a Hungarian settlement on the web, using the open source webGIS system and Google application programming interfaces (APIs). The interactive point and interpolated distribution maps available online provide a detailed picture of the level of contamination, the spatial distribution of the ground water supply of the investigated settlement, and the changes which have occurred following the establishment of the sewage system. In the case of PO43− we determined that in the year before the sewage system was constructed, most of the area of the settlement could be considered contaminated, with the highest level of contamination measured in the central area of the settlement. Five years after the construction of the sewage system, the ratio of the contaminated areas had significantly decreased. In the case of NO3− we found a high level of contamination before the construction of the sewage system with a concentration increase in a North–West direction. After the establishment of the sewage system, the increase in concentration was the most intense in the central parts of the settlement, while the characteristic spatial distribution could no longer be observed. The geovisualization techniques developed are able to provide information about the different spatial data for users in a visual way, and also help to understand better the spatial information using a cognitive approach. The advantage of interactive web maps created with the technologies applied over traditional static maps is a new approach, which allows the user to manipulate the temporal and spatial data directly in the most appropriate way.

Copyright of Agrochemistry & Soil Science / Agrokémia és Talajtan is the property of Akademiai Kiado and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Magyar Radiológia Online is the property of Society of Hungarian Radiologists and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Magyar Radiológia Online is the property of Society of Hungarian Radiologists and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Magyar Radiológia Online is the property of Society of Hungarian Radiologists and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Magyar Radiológia Online is the property of Society of Hungarian Radiologists and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)