The origin of high bicarbonate and fluoride concentrations in waters of the Main Ethiopian Rift Valley, East African Rift system

Gizaw, Berhanu

doi:10.1016/0899-5362(96)00029-2

Cited by 204 publications

(121 citation statements)

References 16 publications

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“…The F -concentration in groundwater depends upon the following factors like climate, relief, evaporation, precipitation, geology, and geomorphology of the area. It is generally accepted that groundwater is enriched in F -due to prolonged water-rock interactions (Saxena and Ahmed 2001;Gizaw 1996;Frengstad et al 2001;Carrillo-Rivera et al 2002). The present study area represents granitic aquifers affected by very high amount of fluoride content with a maximum of 2.2 mg L -1 .…”

Section: Discussionmentioning

confidence: 99%

Contamination of fluoride in groundwater and its effect on human health: a case study in hard rock aquifers of Siddipet, Telangana State, India

2016

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Hydrogeochemical investigation has been carried out in the granitic terrain of Siddipet area, Medak district, Telangana State, India with an aim to understand the distribution of fluoride in the groundwater and to understand the relationship of fluoride with other major ions, and also to identify the high fluoride-bearing groundwater zones. 104 groundwater samples were analyzed in the study area for fluoride and other major ions like calcium, magnesium, chloride, carbonate, bicarbonate, sodium, potassium, sulfate, and nitrate in addition to pH and electrical conductivity. The studies revealed that the concentration of fluoride in groundwater is ranging from 0.2 to 2.2 mg L -1 with a mean of 1.1 mg L -1 . Nearly 22 % of groundwater has more than the permissible limit of fluoride (1.5 mg L -1 ), which is responsible for the endemic dental fluorosis in the area concerned. Geochemical classification of groundwater shows that Na-HCO 3 , Ca-Cl, and Ca-HCO 3 -Na are the dominant hydrochemical facies. Gibbs diagram shows rock-water interaction dominance and evaporation dominance, which are responsible for the change in the quality of water in the hard rock aquifer of the study area. The groundwater in villages and its environs are affected by fluoride contamination, and consequently majority of the population living in these villages suffer from dental fluorosis. Hence, they are advised to consume drinking water which has less than 1.5 mg L -1 fluoride to avoid further fluorosis risks.

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Section: Discussionmentioning

confidence: 99%

Contamination of fluoride in groundwater and its effect on human health: a case study in hard rock aquifers of Siddipet, Telangana State, India

2016

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“…The study was performed in 20 rural communities located in the Ziway-Shala lake basin of the Main Ethiopian Rift (MER) region. Across this zone, large rural populations are chronically exposed to a range of naturally-occurring contaminants in groundwater (Gizaw, 1996;Kilham and Hecky, 1973;Rango et al, 2009Rango et al, , 2010aRango et al, , 2010bReimann et al, 2003), which is one of the main sources for drinking and cooking water.…”

Section: Introductionmentioning

confidence: 99%

The effect of non-fluoride factors on risk of dental fluorosis: Evidence from rural populations of the Main Ethiopian Rift

Kravchenko

Rango

Akushevich

et al. 2014

Science of The Total Environment

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“…In terms of minor elements and considering that some water samples have elevated concentrations of F − (N40 mg/L) typical of other areas in the EARS (Gizaw, 1996), as shown in the Cl − vs. F − diagram of Fig. 6 the Cl/F ratio varies from 1.5 for the northernmost sample of Dimtu to about 40 for some thermal springs of Chawkare.…”

Section: Geochemistry Of Watersmentioning

confidence: 99%

Geothermal potential and origin of natural thermal fluids in the northern Lake Abaya area, Main Ethiopian Rift, East Africa

Minissale

Corti

Tassi

et al. 2017

Journal of Volcanology and Geothermal Research

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In this study, the occurrence, chemical composition, origin and geothermal significance of thermal springs and fumaroles naturally discharging in the area located north of the Lake Abaya (western margin of the Main Ethiopian Rift, East Africa) are reviewed in relation with recent tectonics. All thermal springs showed a dominantly Na-HCO 3 composition, consistent with observations dating from at least 1972, and most of them displayed a narrow range of δD and δ 18 O isotopic compositions for water similar to regional meteoric origins. These observations suggest that water-rock interaction processes occur in all aquifers and dominate the contributions of water that actively circulate within thermal fluids, and also suggest a similar elevation of groundwater recharge throughout the study area. Most of the thermal springs are dominated by a CO 2 -rich gas phase and discharge along the active faults bordering the western edge of the Main Ethiopian Rift valley. The δ 13 C values of CO 2 and the 3 He/ 4 He isotopic ratios are consistent with the presence of mantle-derived fluids similar to what is observed in many other areas along the kinematically active African Rift, especially within Ethiopia. The application of geothermometric techniques in the liquid and the gas phases suggests the presence of a deep reservoir in which the fluids equilibrated at a maximum temperature of approximately 180°C. Additionally, the presence of fumaroles at boiling temperatures and water/mud boiling pools in several places suggests that the geothermal reservoir is positioned at a relatively shallow depth and likely located in the western side of the study area. The analysis of data collected throughout time reveals that the waters of Lake Abaya have experienced an increase in salinity of 20% paralleled contemporaneously with a decrease in pH and δ 18 O and δD of water in the last 40 years; these changes do not appear to be related to climate changeinduced increases in temperature or evaporation at the global scale.

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The origin of high bicarbonate and fluoride concentrations in waters of the Main Ethiopian Rift Valley, East African Rift system

Cited by 204 publications

References 16 publications

Contamination of fluoride in groundwater and its effect on human health: a case study in hard rock aquifers of Siddipet, Telangana State, India

Contamination of fluoride in groundwater and its effect on human health: a case study in hard rock aquifers of Siddipet, Telangana State, India

The effect of non-fluoride factors on risk of dental fluorosis: Evidence from rural populations of the Main Ethiopian Rift

Geothermal potential and origin of natural thermal fluids in the northern Lake Abaya area, Main Ethiopian Rift, East Africa

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