HEAVY METAL AND METALLOID UPTAKE IN FORAGE PLANTS GROWN ON WASTEWATER CONTAMINATED VERTISOL AND FLUVISOL IN AKAKI, ETHIOPIA: A FIELD EXPERIMENT

Due to irrigation with Untreated Wastewater from several Industrial, Commercial, and Domestic Discharges for some decades, Vertisol and Fluvisol accumulated an assortment of Heavy Metals and Metalloids. Consequently, assessment of Potential Environmental Risks and Phytoremediation of the Soils entail information on their simultaneous Uptake and Translocation. The Study, thus, assessed concomitant Soil-to-Shoot transfer of Cr, Co, Ni, Cu, Zn, Cd, Pb, Hg, Se, V, and As employing Oat (Avena sativa), Alfalfa (Medicago sativa), Rhodes (Chloris gayana), Clover [Red] (Trifolium pratense), and Setaria (Setaria sphacelata) under Field Conditions. The Soil Type, Species and Soil Variables (Soil Fractions, CEC and pH: R2 adj., 67?94.2%) significantly (p < 0.05) influenced Shoot Heavy Metal/Metalloid Levels. The levels of most Heavy Metals/Metalloids in the Plants were not only higher than the Natural (Whole-Plant) Contents but also were comparable to or even higher than some Plants from Soils with Polymetallic Pollution. The Soil to Shoot Transfer Coefficients (TC) reached up to 1.25, with higher values observed for most Heavy Metals and Metalloids in Clover and Oat (Vertisol) as well as Setaria and Rhodes (Fluvisol). Generally, the TC values decreased in the order of Cd > Cu > Zn > Se > Cr > As > Ni > Hg > Pb > V > Co, with higher values on Vertisol. Therefore, the data suggest Potential Health Risk for Humans and Livestock via their introduction to the Food Chain that may proceed from the use of Fodder and Vegetables grown on the Soils.