Evaluation of Metals in Soils used for Cultivation of Rhamnus prinoides (Gesho) at Bako Tibe District, Oromiya, Ethiopia

Abstract

This study was carried out with the objective of determining the quantity of selected essential and non-essential metals; K, Na, Mg, Ca, Cu, Mn, Cr, Cd, Fe and Zn in the soil. Samples were collected from the low and medium altitudes of Bako (9°N latitude and 37.17°E). Wet acid-digestion using a mixture of aqua regia (1:3 HNO3 to HCl) and H2O2 (6:1 mL) was used. K and Na were analyzed using flame photometry, Ca and Mg were determined titrimetrically and the other metals with flame atomic absorption spectrometry (FAAS) after appropriate quality control measures were undertaken to verify and maintain the quality of the data generated. The results of the study showed that the average concentrations of K, Ca, Mg, Na, Cu, Mn, Fe, Zn, Cr and Cd were 2401.38, 8920, 633.19, 628.13, 125.79, 39.66, 38.51, 7.28 and 2.41 mg kg-1 and below method detection limit, respectively in the low-altitude; and 3347.38, 10544, 1935.32, 758.13, 113.12, 25.41, 79.94, 50.95 and 3.52 mg kg-1 and below method detection limit, respectively in the medium-altitude. The metals such as K, Ca, Mg, Na and Cu were generally found to be in higher concentrations than other metals in both samples.