Assessment of Microbial Community and Physio-Chemical Properties of Topsoil Stockpiled During Open-Pit Mining

An extensive study was carried out to investigate the changes in the soil microbial community brought about by topsoil storage at Itapke iron-ore deposit, Okene, Nigeria. Experiments on the effect of stockpiling soil at the open-pit iron ore mine at Itakpe showed that there were significant changes in the microbial community. Numbers of aerobic bacteria in stores soils ranged from 0.5 top 12.8 x 177 colony-forming-units (CFU) g-1 with the smallest values being in the deepest parts of the oldest stores, whereas an adjacent undisturbed soil contained 6.6 x 105 CFU g-1 – soil; all less than 10 .x 105 CFU g-1 recorded for undisturbed control soil. The number of fungal spores in the deepest part of the older soil stores was only 1/100 of the number in the undisturbed soil. This was mirrored by the biomass values as determined by Adenosine triphosphate (ATP) assay. Values of ATP ranged from 0.38 to 13.13n mol g-1 as compared to 5.8n mol g-1 in the undisturbed soil. All three of these microbiological properties decreased in value with both age and depth of storage. The pH value tended toward neutrality in the deeper parts of the soil stores and there was less organic matter in the older stores