scholarly journals Geochemical Evolution of Fluoride and Implication for F− Enrichment in Groundwater: Example from the Bilate River Basin of Southern Main Ethiopian Rift

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1799 ◽  
Author(s):  
Muhammed Haji ◽  
Dongdong Wang ◽  
Lu Li ◽  
Dajun Qin ◽  
Yi Guo
Keyword(s):  
River Basin ◽  
Fluoride Concentration ◽  
World Health ◽  
Ethiopian Rift ◽  
Deep Groundwater ◽  
Main Ethiopian Rift ◽  
Deep Aquifers ◽  
Deep Wells ◽  
High Concentrations ◽  
Fluoride Enrichment

Groundwater is the most important source of drinking water. Fluoride was found in high concentrations in the groundwater from deep wells of the water supply in the southern main Ethiopian rift. The high concentration of fluoride is dominantly geogenic rather than anthropogenic in origin, as the agricultural area was not found to be contaminated with NO3−. Knowledge of fluoride enrichment will help to provide management plans for developing deep groundwater and minimizing the health risks of exposure to fluoride. The chemical processes of fluoride were investigated in the waters in the Bilate River basin using hydrochemical and isotopic tools. The F− concentration ranged from 0.5 to 1.29 mg/L in water from shallow wells and from 0.48 to 5.61 mg/L in water from deep wells. Seventy percent of deep well samples had F− > 1.5 mg/L higher than the World Health Organization potable guideline. The high fluoride concentration in the groundwater was mainly situated in the rift valley of the Bilate River basin, in contrast with low F− groundwater in the highland. The concentration of fluoride was lowest in Ca-Mg-HCO3 type groundwater and highest in Na-HCO3 type groundwater. Moreover, F− was positively correlated with HCO3−, Na+, Na+/Ca2+ and pH in groundwater and Na+/Ca2+ ratios were increased along the flow path. Hydrogeological, hydrodynamic and hydrochemical conditions are responsible for fluoride accumulation in the deep aquifers. Strong dynamic flow in highland areas flush away weathered chemical components (e.g., F−). Thus, surficial weathering is not a major controlling factor for high concentrations of Fluoride in deep groundwater but the combination of silicate hydrolysis and ion exchange mainly control fluoride enrichment in stagnant flow environments.

scholarly journals Groundwater Resources in the Main Ethiopian Rift Valley: An Overview for a Sustainable Development

2021 ◽  
Vol 13 (3) ◽  
pp. 1347
Author(s):  
Sabrina Maria Rita Bonetto ◽  
Chiara Caselle ◽  
Domenico Antonio De Luca ◽  
Manuela Lasagna
Keyword(s):  
Water Resources ◽  
Rift Valley ◽  
Local Governments ◽  
Local Development ◽  
Fluoride Concentration ◽  
Shallow Aquifer ◽  
World Health ◽  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Health And Economic Development

In arid and semi-arid areas, human health and economic development depend on water availability, which can be greatly compromised by droughts. In some cases, the presence of natural contaminants may additionally reduce the availability of good quality water. This research analyzed the water resources and hydrochemical characteristics in a rural area of the central Main Ethiopian Rift Valley, particularly in the districts of Shashemene, Arsi Negelle, and Siraro. The study was developed using a census of the main water points (springs and wells) in the area and the sampling and physico-chemical analysis of the water, with particular regard to the fluoride concentration. In many cases, fluoride content exceeded the drinking water limits set by the World Health Organization, even in the absence of anthropogenic contamination. Two different aquifers were recognized: A shallow aquifer related to the eastern escarpment and highlands, and a deep aquifer in the lowland areas of the rift valley on the basis of compositional changes from Ca–Mg/HCO3 to Na–HCO3. The distribution of fluoride, as well as pH and EC values, showed a decrease from the center of the lowlands to the eastern highlands, with similar values closely aligned along an NNE/SSW trend. All these data contribute to creating awareness among and sharing information on the risks with rural communities and local governments to support the adequate use of the available water resources and to plan appropriate interventions to increase access to fresh water, aimed at the sustainable human and rural local development of the region.

Fluoride enrichment mechanism and geospatial distribution in the volcanic aquifers of the Middle Awash basin, Northern Main Ethiopian Rift

2011 ◽  
Vol 60 (5) ◽  
pp. 315-327 ◽  
Author(s):  
Wakgari Furi ◽  
Moumtaz Razack ◽  
Tamiru Alemayehu Abiye ◽  
Tenalem Ayenew ◽  
Dagnachew Legesse
Keyword(s):  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Middle Awash ◽  
Fluoride Enrichment

scholarly journals Origin of Fluoride and Arsenic in the Main Ethiopian Rift Waters

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 453
Author(s):  
Gianluca Bianchini ◽  
Valentina Brombin ◽  
Chiara Marchina ◽  
Claudio Natali ◽  
Tewodros Rango Godebo ◽  
...  
Keyword(s):  
Hot Spring ◽  
Anthropogenic Activities ◽  
Volcanic Rocks ◽  
Lacustrine Sediments ◽  
Volcanic Glass ◽  
Spring Water ◽  
World Health ◽  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Health Organization

In the Main Ethiopian Rift (MER) area, rural populations often use water that exceeds the World Health Organization thresholds for fluoride (F–) and arsenic (As), two elements that are hazardous for human health. In this study, twenty-nine water samples were collected from lakes and hot and cold springs in southern MER to investigate source(s) and health-risk of the F– and As contamination. According to major ion and trace element analyses, only cold spring water is safe for consumption, whereas hot spring water is the most contaminated. Leaching tests performed with the MER rhyolitic volcanic rocks and their weathered products (fluvio-lacustrine sediments) demonstrate that the main cause of the F– and As release is geogenic, i.e., not related to anthropogenic activities. The weathering of volcanic glass and minerals (apatites, clays, hydro-oxides) by CO2-bearing alkaline water induces the mobilisation of F– and As from solid to liquid phase. This process is particularly fast, when fluvio-lacustrine sediments are involved, and can be further enhanced by hot groundwater leaching. This study, investigating the distribution, sources, and mechanisms of F– and As release in MER water, could be of interest also for other sectors of the East African Rift and other similar volcano-tectonic settings.

scholarly journals Installation of Deep Groundwater Wells as Solution to Water Resources Problem in Panggang Subsystem, Gunungsewu Karst Area, Indonesia

2019 ◽  
Vol 125 ◽  
pp. 01009 ◽  
Author(s):  
Indra Agus Riyanto ◽  
Ahmad Cahyadi ◽  
Dwi Sismoyo ◽  
Muhammad Naufal ◽  
Fajri Ramadhan ◽  
...  
Keyword(s):  
Karst Area ◽  
Karst Region ◽  
Deep Groundwater ◽  
Deep Aquifers ◽  
Deep Wells ◽  
Hydrogeological Properties ◽  
Dry Seasons ◽  
Water Provision ◽  
Groundwater Wells ◽  
Geophysical Measurements

The karst area in Panggang Subsystem, Gunungsewu has specific hydrogeological properties, including predominant epikarst springs with minimal discharge in dry seasons. Since this situation inevitably leads to drought, the installation of deep wells to extract water from deep aquifers is proposed as an alternative solution to water provision. This study determined the location of these wells using general geological and geomorphological surveys, followed by analyzing the results of geophysical measurements. The results showed potential aquifers in the sand layer of tertiary volcanic aquifers under the limestone formation that makes the karst region. Although three borewells were constructed at three different points, only two of them succeeded and are ready for use to meet the clean water needs of the population at the research site.

scholarly journals The effect of hydrogeological and hydrochemical dynamics on landslide triggering in the central highlands of Ethiopia

2021 ◽  
Vol 29 (3) ◽  
pp. 1239-1260
Author(s):  
Tesfay Kiros Mebrahtu ◽  
Andre Banning ◽  
Ermias Hagos Girmay ◽  
Stefan Wohnlich
Keyword(s):  
Hydrostatic Pressure ◽  
Groundwater Flow ◽  
Volcanic Rocks ◽  
Chemical Characterization ◽  
Unconsolidated Sediments ◽  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Groundwater Level Fluctuations ◽  
Landslide Mass ◽  
Landslide Triggering

AbstractThe volcanic terrain at the western margin of the Main Ethiopian Rift in the Debre Sina area is known for its slope stability problems. This report describes research on the effects of the hydrogeological and hydrochemical dynamics on landslide triggering by using converging evidence from geological, geomorphological, geophysical, hydrogeochemical and isotopic investigations. The chemical characterization indicates that shallow to intermediate aquifers cause groundwater flow into the landslide mass, influencing long-term groundwater-level fluctuations underneath the landslide and, as a consequence, its stability. The low content of total dissolved solids and the bicarbonate types (Ca–Mg–HCO3 and Ca–HCO3) of the groundwater, and the dominantly depleted isotopic signature, indicate a fast groundwater flow regime that receives a high amount of precipitation. The main causes of the landslide are the steep slope topography and the pressure formed during precipitation, which leads to an increased weight of the loose and weathered materials. The geophysical data indicate that the area is covered by unconsolidated sediments and highly decomposed and weak volcanic rocks, which are susceptible to sliding when they get moist. The heterogeneity of the geological materials and the presence of impermeable layers embodied within the highly permeable volcanic rocks can result in the build-up of hydrostatic pressure at their interface, which can trigger landslides. Intense fracturing in the tilted basalt and ignimbrite beds can also accelerate infiltration of water, resulting to the build-up of high hydrostatic pressure causing low effective normal stress in the rock mass, giving rise to landslides.

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