keywords: Heavy metals, Ricinus communis, phytoextraction, poultry manure, chelants
Pot experiments were designed to investigate the response of R. communis to heavy metals phytoextraction tested under single or mixed chelants and poultry manure assisted scenarios. This was achieved when a moderately contaminated sandy loamy soil was stressed with a 500 mgkg-1 conjointly metal (Cd, Cu, Pb), blended with; single or mixed chelant (EDTA and oxalic acid) and poultry manure. After growth, the maximum heights and leaf breadths of R. communis were; 5.01-69.0 and 1.90-38.4 cm, with plants typically luxuriant and greenish. pH, bulk density, electric conductivity, organic carbon, of the parent soil were determined. The results revealed that pH (6.21), (9.30 cmol Kg-1), BD (1210 kg/m3), OM (8.63 %) were found in the parent soil used. Pseudo-total metal concentration (mgkg-1) of the metals (Cd, Cu and Pb) were; 10.2, 8.93 and 5.22, respectively. Maximum tissue metal concentrations in the various potting media were: soil-metal-PM-EDTA+OX (436.0-490.6 mg Cd/kg; 453.2-475.5 mg Cu/kg; 452.3-469.8 mg Pb/kg. Maximum values for Cd, Cu and Pb root bioaccumulation factor (RBf), shoot bioaccumulation factor (SBf), and translocation factor (Tf) were; 0.68, 0.29 and 0.42; 0.67, 0.28 and 0.42; and 0.66, 0.27 and 0.41, respectively. Pot experiments revealed high metal transferabilities with no apparent phytotoxic symptoms in R. communis at the doses applied, suggesting some degree of tolerance to the metals. Overall, the binary chelant treatments were less toxic for R. communis growth and enhanced metal accumulation in shoots to a greater extent than the single chelant scenarios, but more so when EDTA was present in the binary combination.