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Bottom sediment samples were collected from pools of watercourses, and soil samples were collected from the surface horizon at different areas of the tailing dump. All samples were placed in clean plastic bags, labelled, and dried to dry-air condition. In the lab, the bottom sediment and tailing samples were sieved, and the fraction less than 0.1 mm was separated. Weighed quantities of 0.2 g were collected in triplicate, dissolved in 5 ml of high purity nitric acid, and mineralized in a Mars Express microwave oven (CEM Corporation, USA).