Characterization of contaminants in the streams and the agricultural lands through residual dispersal from a derelict gold mine

The abandoned Kubong gold mine has been an active source of acidity and trace metals to the adjacent agricultural lands throughout drainage and sediment loading resulting from severe erosion during the summer for approximately 30 yeas. This study was to conduct to characterize the distribution patterns of the heavy metals in surface and subsurface soils to better understand the potential threat local ground and surface water quality. The result shows that the amounts of heavy metals are in the order of a upland soil, a paddy soil, while mine wastes and sediment along the streams are sampled and analyzed for heavy metals by extracting with different solutions. The pH’s are 5.3, 4.9, 8.2 for a paddy soils, upland soils, and stream sediment, respectively. It is our belief that the conditions of pH may affect the mobility. However, the distribution of the heavy metals vary with depth and ionic species, resulting in that the flooding during the growth period in a paddy soils influence the transport of these heavy metals, as well as a competitive adsorption for sorption sites among the heavy metals. Therefore, we may conclude that the distribution pattern of the heavy metals observed are influenced by the soil pH, plant establishment, water flow characteristics, and competition among cations in this derelict gold mine.