scholarly journals Hydrochemical Characterisation of High-Fluoride Groundwater and Development of a Conceptual Groundwater Flow Model Using a Combined Hydrogeological and Hydrochemical Approach on an Active Volcano: Mount Meru, Northern Tanzania

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2159
Author(s):  
George Bennett ◽  
Jill Van Reybrouck ◽  
Ceven Shemsanga ◽  
Mary Kisaka ◽  
Ines Tomašek ◽  
...  
Keyword(s):  
Drinking Water ◽  
Large Scale ◽  
Active Volcano ◽  
Aquifer System ◽  
Groundwater Samples ◽  
Northern Tanzania ◽  
Different Seasons ◽  
High Fluoride ◽  
Arusha National Park ◽  
The Impact

This study characterises high-fluoride groundwater in the aquifer system on the flanks of Mount Meru, focusing on parts of the flanks that were only partially or not at all covered by previous research. Additionally, we analyse the impact of rainwater recharge on groundwater chemistry by monitoring spring discharges during water sampling. The results show that the main groundwater type in the study area is NaHCO3 alkaline groundwater (average pH = 7.8). High F− values were recorded: in 175 groundwater samples, the concentrations range from 0.15 to 301 mg/L (mean: 21.89 mg/L, median: 9.67 mg/L), with 91% of the samples containing F− values above the WHO health-based guideline for drinking water (1.5 mg/L), whereas 39% of the samples have Na+ concentrations above the WHO taste-based guideline of 200 mg/L. The temporal variability in F− concentrations between different seasons is due to the impact of the local groundwater recharge. We recommend that a detailed ecohydrological study should be carried out for the low-fluoride springs from the high-altitude recharge areas on the eastern and northwestern flanks of Mount Meru inside Arusha National Park. These springs are extracted for drinking purposes. An ecohydrological study is required for the management of these springs and their potential enhanced exploitation to ensure the sustainability of this water extraction practice. Another strategy for obtaining safe drinking water could be to use a large-scale filtering system to remove F− from the groundwater.

scholarly journals Estimation and impact of carbon dioxide capture on drinking water: Tillmans equilibrium diagram

2019 ◽  
Vol 11 (2) ◽  
pp. 380-389
Author(s):  
C. Alvarez-Bastida ◽  
M. Solache-Ríos ◽  
I. Linares-Hernández ◽  
G. Vázquez-Mejía ◽  
G. Fonseca-Montes de Oca ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Drinking Water ◽  
Carbonic Acid ◽  
Carbon Dioxide Capture ◽  
Equilibrium Diagram ◽  
Cation Composition ◽  
Bicarbonate Ions ◽  
Different Seasons ◽  
User Friendly ◽  
The Impact

Abstract The increase of CO2 in the atmosphere may produce some effects on drinking water because water tends to naturally capture CO2 species. The main purpose was the study of the impact of capture of free CO2 and its transformation to carbonic acid (H2CO3) and bicarbonate ions (HCO−3). The study used a Tillmans equilibrium diagram obtained from the modified Mojmir Mach model as a function of water temperature and considered the effects on anion and cation composition. Three wells located in different zones were selected, with similar characteristics (capture of CO2). Samples were taken in different seasons of the year and the amount of CO2 in the drinking water was calculated. It was found that with increasing concentrations of free CO2 the pH decreases, and this process makes the water acid and susceptible to dissolve some elements (Ca, Na, K, Si) and other species (HCO−3). The capture of CO2 has important effects on the anion and cation composition of drinking water and on the variation of pH by more than one unit, which may affect the health of consumers. The method presented in this study is an excellent user-friendly alternative to determine the impact of natural capture of total CO2 by water.

scholarly journals Impact of pressure dissipation on fluid injection into layered aquifers

2019 ◽  
Vol 877 ◽  
pp. 214-238
Author(s):  
Luke T. Jenkins ◽  
Martino Foschi ◽  
Christopher W. MacMinn
Keyword(s):  
Large Scale ◽  
Water Pressure ◽  
Gravity Current ◽  
Fluid Injection ◽  
Sharp Interface Model ◽  
Two Phase ◽  
Vertical Pressure ◽  
Aquifer System ◽  
Mitigate Climate Change ◽  
The Impact

Carbon dioxide ($\text{CO}_{2}$) capture and subsurface storage is one method for reducing anthropogenic $\text{CO}_{2}$ emissions to mitigate climate change. It is well known that large-scale fluid injection into the subsurface leads to a buildup in pressure that gradually spreads and dissipates through lateral and vertical migration of water. This dissipation can have an important feedback on the shape of the $\text{CO}_{2}$ plume during injection, but the impact of vertical pressure dissipation, in particular, remains poorly understood. Here, we investigate the impact of lateral and vertical pressure dissipation on the injection of $\text{CO}_{2}$ into a layered aquifer system. We develop a compressible, two-phase model that couples pressure dissipation to the propagation of a $\text{CO}_{2}$ gravity current. We show that our vertically integrated, sharp-interface model is capable of efficiently and accurately capturing water migration in a layered aquifer system with an arbitrary number of aquifers. We identify two limiting cases – ‘no leakage’ and ‘strong leakage’ – in which we derive analytical expressions for the water pressure field for the corresponding single-phase injection problem. We demonstrate that pressure dissipation acts to suppress the formation of an advancing $\text{CO}_{2}$ tongue during injection, reducing the lateral extent of the plume. The properties of the seals and the number of aquifers determine the strength of pressure dissipation and subsequent coupling with the $\text{CO}_{2}$ plume. The impact of pressure dissipation on the shape of the $\text{CO}_{2}$ plume is likely to be important for storage efficiency and security.

scholarly journals Infiltration processes in karst aquifers affected by large-scale forest disturbances

2021 ◽  
Author(s):  
Urša Vilhar ◽  
Mitja Ferlan ◽  
Janez Kermavnar ◽  
Erika Kozamernik ◽  
Aleksander Marinšek ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Balance ◽  
Large Scale ◽  
Karst Aquifer ◽  
Karst Water ◽  
Forest Disturbances ◽  
Forest Development ◽  
Development Phases ◽  
The Impact ◽  
Infiltration Processes

<p>Karst systems represent 10–15% of land surface in the world and supply around 25% of the global demand for drinking water. In Slovenia karst areas are merely covered by forest and important for their rich and unique ecosystems. However, prevailing beech and mixed fir-beech forests in the region have been exposed to severe large-scale disturbances in the past few years, e.g., ice storms and heavy snow, windthrow, severe and prolonged periods of droughts and secondary insect damage, which have caused episodes of forest decline. Modification of the vegetation cover indirectly impacts the water balance. Despite the important role of karst water resources for supplying the population with drinking water, few studies exist that adequately evaluate the impact of predicted global changes on their quantity and quality. The effects of large-scale forest disturbances have been only marginally addressed, despite evaporation of water from the soil and epikarst being recognized as a significant process affecting hydrological cycle in karst regions. In many hydrological studies, the role and importance of vegetation in infiltration mechanisms, in particular the effect of trees and their root networks, has been widely neglected. In this study we present a holistic approach to infiltration processes research. An in-situ environmental monitoring network of the atmosphere-vegetation-soil-unsaturated zone of the aquifer has been designed to better understand infiltration in different compartments of the karst aquifer. Special focus is given to different forest development phases after large-scale disturbances and karst terrain morphology. The amount of precipitation in the open, canopy interception in mature forest and in canopy gaps with varying forest development phases, soil moisture and soil temperature are measured on the surface and subsurface. These measurements are performed in the area of an eLTER site Postojna-Planina cave system, i.e., on the top and bottom of karst depressions, while in the underground water discharge and electrical conductivity are measured in cave drips. By observing the time lag of the measured parameters to the recharge events, the effective infiltration of precipitation into the aquifer is evaluated and quantified. The results enabled to distinguish the recharge conditions under different forest development phases after large-scale disturbances and under different geomorphological conditions. The findings will in the later stage of the research serve as an input information for coupled vegetation-hydrological modelling of recharge conditions. Upscaling the modelling results from local to entire catchment scale would be useful for the evaluation of impacts of large-scale forest disturbance on the water balance of the entire karst aquifer system.</p>

scholarly journals GEOLOCATION SUPPORT FOR WATER SUPPLY AND SEWERAGE PROJECTS IN AZERBAIJAN

2016 ◽  
Vol XLI-B4 ◽  
pp. 777-781
Author(s):  
M. H. Qocamanov ◽  
Ch. Z. Gurbanov
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Large Scale ◽  
Detailed Examination ◽  
Drinking Water Supply ◽  
Sewerage System ◽  
Large Cities ◽  
Geodetic Measurements ◽  
Reliable Performance ◽  
The Impact

Drinking water supply and sewerage system designing and reconstruction projects are being extensively conducted in Azerbaijan Republic. During implementation of such projects, collecting large amount of information about the area and detailed investigations are crucial. Joint use of the aerospace monitoring and GIS play an essential role for the studies of the impact of environmental factors, development of the analytical information systems and others, while achieving the reliable performance of the existing and designed major water supply pipelines, as well as construction and exploitation of the technical installations. With our participation the GIS has been created in “Azersu” OJSC that includes systematic database of the drinking water supply and sewerage system, and rain water networks to carry out necessary geo information analysis. GIScreated based on “Microstation” platform and aerospace data. <br><br> Should be mentioned that, in the country, specifically in large cities (i.e. Baku, Ganja, Sumqait, etc.,) drinking water supply pipelines cross regions with different physico-geographical conditions, geo-morphological compositions and seismotectonics.Mains water supply lines in many accidents occur during the operation, it also creates problems with drinking water consumers. In some cases the damage is caused by large-scale accidents. Long-term experience gives reason to say that the elimination of the consequences of accidents is a major cost. Therefore, to avoid such events and to prevent their exploitation and geodetic monitoring system to improve the rules on key issues. Therefore, constant control of the plan-height positioning, geodetic measurements for the detailed examination of the dynamics, repetition of the geodetic measurements for certain time intervals, or in other words regular monitoring is very important. During geodetic monitoring using the GIS has special significance. Given that, collecting geodetic monitoring measurements of the main pipelines on the same coordinate system and processing these data on a single GIS system allows the implementation of overall assessment of plan-height state of major water supply pipeline network facilities and the study of the impact of water supply network on environment and alternatively, the impact of natural processes on major pipeline.

scholarly journals Impact of Solid Waste Dumpsite on Groundwater Quality in the Neighbouring Communities

2019 ◽  
pp. 1-12
Author(s):  
O. V. Ajibade ◽  
P. O. Ogungbile ◽  
M. K. C. Sridhar ◽  
A. O. Coker
Keyword(s):  
Drinking Water ◽  
Solid Waste ◽  
World Health ◽  
Chemical Parameters ◽  
Drinking Water Contamination ◽  
Groundwater Aquifer ◽  
Physico Chemical ◽  
Groundwater Samples ◽  
Local Ecosystem ◽  
The Impact

Leachate seepages into groundwater aquifer from solid waste dumpsites is likely to release toxic pollutants in groundwater which are hazardous to human health and local ecosystem. A study was conducted on the Physico-chemical parameters of dumpsite leachate and surrounding groundwater from Awotan Solid Waste Dumpsite, in Ibadan, Oyo State. The study was aimed at assessing the impact of the leachate from the dumpsite. The physicochemical analyses of the water samples were carried by standard analytical methods. The results obtained were compared with the WHO (World Health Organization) permissible limit of those parameters in drinking water. The Physico-chemical values obtained for the dumpsite leachate were generally higher than those of groundwater samples, suggesting that a source of contamination could be from the dumpsite leachate. The pH of groundwater samples ranged between 5.03 to 6.94, indicating that the groundwater was acidic. Results of Physico-chemical parameters of dumpsite leachate for Cl-, NO3, TH, Alk, BOD, COD exceeded the WHO limits for drinking water. The BOD and COD of dumpsite leachate and groundwater samples exceeded the WHO limits and hence not safe for drinking. The concentration of Cl- and TH in the groundwater closer to the dumpsite were higher than WHO permissible limits for drinking water. Also, concentrations of the analyzed parameters decreased with increasing distance from the dumpsite, thus implicating leachate seepage from the dumpsite into the groundwater. It is therefore recommended that dumpsites be located away from the human settlements to avoid drinking water contamination and local ecosystem & biodiversity degradation.

scholarly journals Prospecting for safe (low fluoride) groundwater in the eastern African Rift: a multidisciplinary approach in the Arumeru District (northern Tanzania)

2009 ◽  
Vol 6 (6) ◽  
pp. 7321-7348 ◽  
Author(s):  
G. Ghiglieri ◽  
R. Balia ◽  
G. Oggiano ◽  
D. Pittalis
Keyword(s):  
Multidisciplinary Approach ◽  
Methodological Approach ◽  
Water Shortage ◽  
The North ◽  
Northern Tanzania ◽  
Electrical Sounding ◽  
High Fluoride ◽  
African Rift ◽  
Arusha National Park ◽  
Semi Arid

Abstract. This research was aimed at finding fresh and safe groundwater easily deliverable to an area, located in northern Tanzania, within the western branch of the Rift Valley. The study area suffers from water shortage, moreover, due to widespread alkaline volcanism, high fluoride contents (F− up to 70 mg/l) affects the groundwater. The achievement of this goal has been pursued through a multidisciplinary research consisting of geological, hydrogeological, hydro-chemical, geophysical and hydrological investigations. The study area stretches over 440 km2 and lies in the northern part of the Arumeru District, approximately 50 km from Arusha, the capital of the region. The Mount Meru (4565 m a.s.l.) and the Arusha National Park mark the boundary of the area, which includes 9 villages belonging to the Oldonyo Sambu and Ngarenanyuki Wards. The climate is semi-arid, with dry and relatively rainy seasonal alternance. Four principal hydrogeological complexes have been identified within different lithologies. They occur within volcanic formations, singularly or superimposed on each other. Subordinate perched aquifers are present in sedimentary formations with local occurrence. The groundwater flow system has been interpreted on the basis of springs spatial distribution combined with lithological and the geometrical reconstruction of the aquifers. The dominant pattern, consisting of multidirectional flow from the higher elevation area in the south towards the lower area in the north, is complicated by the occurrence of structures such as grabens, faults, lava domes and tholoids. After the identification of the main fluoride source, an interference pattern among groundwater and high F surface water was drawn. Finally, some VES (Vertical Electrical Sounding) were performed that allowed an aquifer to be individuated within a structural high where the fluoride input is prevented. The drilling of a well, able to supply at least 3.8 l/s of low fluoride, drinkable water, successfully concluded the methodological approach for prospecting safe water in a semi-arid, naturally fluoride polluted region.

scholarly journals Trends in Nitrate Pollution of Groundwater in Denmark

1984 ◽  
Vol 15 (4-5) ◽  
pp. 177-184 ◽  
Author(s):  
Kurt Overgaard
Keyword(s):  
Time Series ◽  
Drinking Water ◽  
Regional Differences ◽  
Mean Value ◽  
Maximum Admissible Concentration ◽  
Groundwater Samples ◽  
Geological Conditions ◽  
Nitrate Concentrations ◽  
The Impact

A nation-wide investigation of nitrate concentrations in groundwater in Denmark has been carried out. The investigation is based on analyses of groundwater samples from app. 11,000 wells and drinking water from 2,800 groundwaterworks spread equally all over the country, 43,000 km2. Furthermore the trends in nitrate concentrations have been investigated on the basis of time-series of nitrate concentrations for 184 waterworks. The investigation shows that: - the overall mean level of nitrate concentrations in the groundwaters has trebled within the last 20-30 years, - there are pronounced regional differences in the nitrate concentrations of the groundwaters and in the trends of the nitrate concentrations, - in the western parts of the country the groundwaters are more seriously affected than in the eastern parts and rising trends are significantly more pronounced, - 36% of the investigated time-series of nitrate concentrations in drinking water from 184 groundwaterworks show a rising trend of 1 to 6 mg NO3/1 per year with a mean value of 3.3, and there is no sign of levelling off, - drinking water from 8% of the waterworks exceed the EEC maximum admissible concentration for nitrate of 50 mg/1 and 18% EEC guide level of 25 mg/1. The causes of the general rising trends in the nitrate concentrations in the groundwaters and the regional differences of the trends are discussed. In particular, the impact of agricultural activities and the role of the geological conditions are considered.

Impact of COVID-19 on Nuclear Medicine in Germany, Austria and Switzerland: An International Survey in April 2020

2020 ◽  
Vol 59 (04) ◽  
pp. 294-299 ◽  
Author(s):  
Lutz S. Freudenberg ◽  
Ulf Dittmer ◽  
Ken Herrmann
Keyword(s):  
Nuclear Medicine ◽  
Health Systems ◽  
Personal Protective Equipment ◽  
Large Scale ◽  
Diagnostic Procedures ◽  
Protective Equipment ◽  
Current Crisis ◽  
Web Based ◽  
Public Versus Private ◽  
The Impact

Abstract Introduction Preparations of health systems to accommodate large number of severely ill COVID-19 patients in March/April 2020 has a significant impact on nuclear medicine departments. Materials and Methods A web-based questionnaire was designed to differentiate the impact of the pandemic on inpatient and outpatient nuclear medicine operations and on public versus private health systems, respectively. Questions were addressing the following issues: impact on nuclear medicine diagnostics and therapy, use of recommendations, personal protective equipment, and organizational adaptations. The survey was available for 6 days and closed on April 20, 2020. Results 113 complete responses were recorded. Nearly all participants (97 %) report a decline of nuclear medicine diagnostic procedures. The mean reduction in the last three weeks for PET/CT, scintigraphies of bone, myocardium, lung thyroid, sentinel lymph-node are –14.4 %, –47.2 %, –47.5 %, –40.7 %, –58.4 %, and –25.2 % respectively. Furthermore, 76 % of the participants report a reduction in therapies especially for benign thyroid disease (-41.8 %) and radiosynoviorthesis (–53.8 %) while tumor therapies remained mainly stable. 48 % of the participants report a shortage of personal protective equipment. Conclusions Nuclear medicine services are notably reduced 3 weeks after the SARS-CoV-2 pandemic reached Germany, Austria and Switzerland on a large scale. We must be aware that the current crisis will also have a significant economic impact on the healthcare system. As the survey cannot adapt to daily dynamic changes in priorities, it serves as a first snapshot requiring follow-up studies and comparisons with other countries and regions.

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