| dc.description.abstract | A study was carried out to assess the efficiency of Pleurotus ostreatus in the mycoremediation of soil contaminated with three heavy metals (nickel, copper and cobalt) in Kilembe, Kasese District, Western Uganda. The initial concentrations of the metals were measured in five 5 kg soil samples obtained 10m from tailing dams. After disinfection, the soil was placed in sacks A, B, C, D, and E. To sacs A and B, about 2kg of wet sawdust was added as the growth substrate while to sacs C and D 2 kg of wet millet straw was added. No substrate was added to E. After 28 days the mushrooms had grown out the bags, a soil sample was then collected from each of the five sacs for analysis of the remaining metal concentrations of (nickel, copper and cobalt). The concentrations of three elements Cu, Co, Ni before and after the experiment were determined using Flame Atomic Absorption Spectrophotometer. The soils collected before the experiment tailings contained high concentrations of Cu, Co and Ni which were significantly higher than the world crust average in the order of Cu> Ni> Co. The initial average concentration of Cu in the soil analyzed was in the range of 110mg/kg to 5270mg/kg compared to world crust average of 20-75mg/kg as described by Kabata-Pendias (2011). The initial average concentration of Co was in the range of 46 mg/kg to 82mg/kg as compared to the world crust average 1–15 mg/kg (Kabata-Pendias, 2011). The initial average concentration of Ni was in the range of 64mg/kg to 113 mg/kg as compared with world crust mean of 20 mg/kg (Kabata-Pendias (2011). Analysis of the soils after the growth of the mushrooms showed that Ni was the most adsorbed metal followed by Cu and then Co. After the harvest the concentration range of Ni was 54mg/kg to 104mg/kg while that of Cu and Co was 98mg/kg to 4690mg/kg and 45mg/kg to 75mg/kg respectively. The statistical analysis was done using the R package software, a paired t-test was done and it showed that there was a significant reduction in the concentration of copper at p-value = 0.07777, no significant reduction in the concentration of cobalt after the experiment at p-value = 0.04136 and a significant reduction in the concentration of nickel at p-value = 0.07882 and 95% confidence interval. The ability of Pleurotus Ostreatus to decrease heavy metal concentration in soil is a matter of fact as explained in the report below. The growth morphology in soil (i.e., extended hyphal network), the low specificity of extracellular enzymatic complexes and the possibility to use toxic compounds as the growth substrate make filamentous fungi more advantageous in bioremediation processes when compared to other microorganisms. | en_US |
