%0 Journal Article
%T Hydrochemical and stable isotopic characterization of shallow groundwater system in the crystalline basement terrain of Ekiti area, southwestern Nigeria
%A Abel O. Talabi
%A Moshood N. Tijani
%J Applied Water Science
%@ 2190-5495
%D 2013
%I Springer
%R 10.1007/s13201-013-0076-3
%X Assessments of hydrochemical quality and recharge source are critical components of sustainable groundwater resources evaluation and management, especially in complex weathered/fractured crystalline bedrock terrains. Assessment of the weathered/fractured basement aquifer of Ekiti area, SW-Nigeria was undertaken with emphasis on hydrochemical quality and stable isotope characterization of shallow groundwater system. The study approach involved field sampling and in situ measurements of physico-chemical parameters followed by hydrochemical and stable isotope analyses of the water samples. In situ measurements revealed EC value of 43¨C995 ¦ÌS/cm (av 431.96 ¦ÌS/cm) and total hardness of 31.3¨C295.1 mg/L. The pH of the water sample ranged from 7.0 to 8.9 (av 8.00). The concentrations of the major cations are in the order of Ca2+ > K+ > Na+ > Mg2+ with their respective average values of 33.35, 25.61, 24.91 and 8.7 mg/L respectively while that of the anions are in the order of HCO3   > Cl  > SO4 2  > NO3   with their respective average values of 165.44, 31.85, 21.27 and 5.44 mg/L respectively. However, the results of stable isotope analyses revealed ¦Ä18O value of  4.2 to  2.1 ¡ë and ¦ÄD of  22.3 to  10.2 ¡ë, suggesting meteoric water source (recent precipitation water recharging the associated shallow basement aquifer) while the estimated deuterium excess of 6.80¨C11.00 ¡ë (av 9.6 ¡ë) suggested little or no imprint of kinetic evaporation. Furthermore, the overall hydrochemical profiles revealed the main hydrochemical facies as Ca(Mg)-HCO3 (dominant) and Na(K)-HCO3 (minor) water types which can be attributed to dissolution of minerals in the various rock units in the study area. Conclusively, the overall hydrochemical and stable isotope evaluations revealed a recharge predominantly derived from meteoric (rainfall) source while the corresponding low TDS is a reflection of low water¨Crock interaction and limited migratory history of the shallow groundwater system in the study area.
%K Shallow groundwater
%K Basement terrain
%K Hydrochemical facies
%K Stable isotope
%K Meteoric water
%U http://link.springer.com/article/10.1007/s13201-013-0076-3