title: Tracing stable isotopes (δ²H and δ¹⁸O) from meteoric water to groundwater in the Densu River basin of Ghana.
abstract: This study represents the first attempt to study soil water δ(18)O profiles in Ghana using a mechanical auger. In this paper, the characteristics of δ(18)O and δ(2)H in rain water, surface water, soil water and groundwater have been used to understand the transformation mechanism of rain water to groundwater. Rain waters were sampled in Koforidua and Accra. Surface water and groundwater were sampled from the Densu River and selected boreholes in the basin, respectively. Soil waters were taken from three typical sites, namely, Potroase (POT), Teacher Mante (TM) and Ayikai Doblo (AD) in the northern, middle and southern zone from 0.00- to 6-m depth. The soil water was extracted using vacuum distillation method. The distribution of the stable isotopes of rain water is influenced by rainfall amount with minimal temperature effect. In general, the soil water is of meteoric origin undergoing fractionation-controlled evaporation. In the middle zone, the soil water shows some evidence of recharge from enriched source. The three profiles show similar trend of enriched values in the upper depths with gradual depletions of δ(18)O with depth. The POT profile showed relatively more depleted values suggesting a fast infiltration. In all the three profiles, soil waters below 3 m were found to contribute to groundwater recharge with piston flow as the dominant mechanism. The study also revealed that there is a significant contribution of enrich source to the groundwater system leading to the dilution of the infiltrating water by the large aquifer.
authors.affiliation: Nuclear Chemistry and Environmental Research Centre, National Nuclear Research Institute, Ghana Atomic Energy Commission, Box LG 80, Kwabenya-Accra, Ghana.
authors.forename: Dickson
authors.initials: D
authors.lastname: Adomako
authors.forename: Abass
authors.initials: A
authors.lastname: Gibrilla
authors.forename: Piotr
authors.initials: P
authors.lastname: Maloszewski
authors.forename: Samuel Yao
authors.initials: SY
authors.lastname: Ganyaglo
authors.forename: Shive Prakash
authors.initials: SP
authors.lastname: Rai
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D005869:Ghana; D060587:Groundwater / Q000737:chemistry*; D006859:Hydrogen / Q000032:analysis; D007554:Isotopes; D010103:Oxygen Isotopes / Q000032:analysis; D011891:Rain / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D012987:Soil; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D007554:Isotopes; D010103:Oxygen Isotopes; D012987:Soil; D014874:Water Pollutants, Chemical; D006859:Hydrogen