Evaluation of Dacryodes edulis (native pear) seed biomass for Pb (II) sorption from aqueous solution

Dacryodes edulis (Native pear) seed is herein evaluated as a promising biomass for Pb(II) removal from aqueous solution. The Pb(II) adsorption onto Dacryodes edulis seed biomass was influenced by the solution pH, time, biomass dose and initial adsorbate concentration. The Freundlich model fitted better than the Langmuir model which also gave a good fit when the experimental data were represented on both isotherm models. The kinetic data clearly established the pseudo – second order model as a more appropriate model for describing the Pb(II) ion sorption onto pulverized seed of Dacryodes edulis. This investigation shows that at pH 5, biomass concentration, 50 mg/L; temperature 28 oC and contact time 90 minutes, a Langmuir monolayer adsorption capacity of 10.42 mg/g was obtained. This is an indication that the native peer seed is an efficient biosorbent for Pb(II) ions removal from aqueous environment.Keywords: Dacryodes edulis, kinetics, isotherms, uptake and adsorption efficienc

Concentrations of Selected Metals In Some Ready-To-Eat-Foods Consumed in Southern Nigeria: Estimation of Dietary Intakes and Target Hazard Quotients

Concentrations of selected metals (Cu, Cd, Ni, Pb, Mn, Fe, Zn, Cr and Co) in some ready-to-eat-foods consumed in Nigeria were investigated with a view providing information on the risk associated with the consumption of these products. The concentrations of metals (mg.kg-1) in these ready-to-eat-foods are in the ranges of 2.4 – 5.2 for Cu; 0.1– 0.8 for Cd; 0.7 – 4.0 for Ni; 8.1 – 53.7 for Fe; 8.9 – 20.0 for Zn; 0.1 – 3.8 for Pb; 5.1 – 14.4 for Mn; 0.83 – 21.4 for Cr and 0.20 – 1.32 for Co. The concentrations and estimated intakes of Cd, Ni and Pb in some of these food types exceeded the permissible limits and tolerable daily intake respectively. The target hazard quotients (THQ) for the individual metals indicate levels of concern for Ni, Cd, and Co in some of the ready-to-eat-foods. The combined THQ values for the metals in the examined samples ranged from 1.7 to 10 with significant contributions from Cd, Ni and Co.</jats:p