Heavy metal analysis in the soils of in and around Robe town, Bale zone, South Eastern, Ethiopia

摘要

The purpose of this study was to assess physicochemical parameter and heavy metal concentration of the soil in and around Robe town, Bale zone, Ethiopia. Seven soil samples (three from dump sites and four from farm lands) were collected and analyzed through different methods for analyzing the physicochemical parameters like, pH Sand/Silt/Clay Content, MC, OM. and the heavy metals including Cr, Cd, Cu, Fe, Zn and Pb, were investigated using Flame atomic absorption spectrophotometer (FAAS). The analyzed result of all sites revealed that, high moisture content % (14.83 ± 2.57to 19.96 ± 0.72), pH slightly acidic except S2 which is slightly basic, (5.77 ± 0.08 to 7.60 ± 0.33),high organic matter % (13.83 ± 0.49 to 16.60 ± 0.90), sand % (53.00 ± 4.51 to 65.33 ± 2.42), silt % (19.33 ± 1.03 to 24.84 ± 4.62), clay % (11.33 ± 1.03 to 19.50 ± 2.50) sandy nature of soil were observed and the concentration of heavy metals such as: Cr (32.53 ± 3.51 to 41.81 ± 1.06) ppm, Cd (0.57 ± 0.21 to 0.93 ± 0.24) ppm, Cu (26.54 ± 0.68 to 37.44 ± 2.72) ppm, Zn (66.98 ± 1.09 to 170.48 ± 1.51) ppm Fe (33483.55 ± 1470.02 to 49012.18 ± 2692.20) ppm and Pb (18.04 ± 0.37 to 20.77±0.46) ppm were obtained. The results showed that all of the assessed heavy metals below maximum permissible limit except Fe, which is above maximum permissible limit that recommended by Ewers, Based on the results obtained from the study the level of metals concentrations safe for agricultural activities. But different measures must be taken to minimize additional soil pollution.