Fluoride Genesis in Groundwater of Butajira _Koshe _Ziway Transects Areas Using Integrated Hydrochemistry and Isotope Techniques, in Central Ethiopia
| dc.contributor.advisor | Azagegn, Tilahun (PhD) | |
| dc.contributor.author | Admas, Temesgen | |
| dc.date.accessioned | 2018-06-20T07:23:56Z | |
| dc.date.accessioned | 2023-11-09T14:09:22Z | |
| dc.date.available | 2018-06-20T07:23:56Z | |
| dc.date.available | 2023-11-09T14:09:22Z | |
| dc.date.issued | 2001-06 | |
| dc.description.abstract | This research is conducted to investigate fluoride problems with it genesis in groundwater of Butajira_Koshe_Ziway transect of central main Ethiopian rift by using integrated hydro chemical and isotope analysis techniques. The hydrochemical analysis result reveals that groundwater type of the area evolves from Ca(Mg)-HCO3water type of early geochemical evolution in the western highlands and escarpments to Na-HCO3 water type of highly geochemical evolution in the rift floor (i.e. towards lake Ziway) of the study area. Groundwater supplied from the highlands is typically characterized by low conductivity, low TDS, and a calcium bicarbonate facies. The water geochemistry (i.e fluoride content) within the study area is widely (extremely) variable due to meteoric water recharge from the surrounding highlands is affected by different degrees of water–rock interaction ,evaporation processes, rock type, depth variation, chemical and physical characteristics of the aquifer and acidity of soil and rock, concentration of ion present in the water. The high F geochemical anomaly is associated with high Na (R2=0.37), alkalinity (R2=0.25), TDS, EC (R2=0.3), shallow depth and low calcium content. In general, from correlation matrix of collected and analyzed water sample, there is a negative correlation between calcium, magnesium and fluoride concentrations and positive correlation between bicarbonate, TDS, EC and fluoride concentration in groundwater. Saturation indices (SI) were calculated (using PHREEQC) for the different water groups, highlighting that the studied waters are super saturated with respect to calcite and under saturated with respect to fluorite. Groundwater is supersaturated with respect to calcite, which promotes the removal of Ca and HCO3 from solution. As a result, groundwater is generally under saturated with respect to fluorite, the mineral that typically controls the upper limit of fluoride concentrations. The stable isotopes result reveals that highly enriched water from hand dug well, few borehole well and lake itself were observed in the downstream part of the study area surrounding the lake Ziway due to evaporation effect and recharged from the lake water rather than precipitation from highlands while the deep ground water located in the highland and escarpment of the study area reveal that slightly to highly depleted due to it recharged at lower temperature/from local meteoric water directly infiltrated rainfall through long subsurface flow from Guragae highland. The general trend for groundwater flow observed from groundwater contour map, hydro chemical evolution and isotopic signature indicates that from western highlands toward the rift floor in the direction of NW to SE of the study area. Keywords: Fluoride genesis; Ground water flow; Hydrochemistry; Stable isotope (δ18O, δ2H) | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/2052 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | : Fluoride genesis; Ground water flow; Hydrochemistry; Stable isotope (δ18O, δ2H) | en_US |
| dc.title | Fluoride Genesis in Groundwater of Butajira _Koshe _Ziway Transects Areas Using Integrated Hydrochemistry and Isotope Techniques, in Central Ethiopia | en_US |
| dc.type | Thesis | en_US |