MIGRATION OF HEAVYMETALS IN THE UPPER HORIZONS OF MININGSOIL: THE CASE OF THE FORMER POURA MINE (BURKINA FASO)

The presence of contaminants in an environment and their mobility depend greatly on the nature of the environment, climatic and geological conditions,and anthropogenic influences. Soil contamination by these heavy metals poses a significant public health risk due to the various diseases they can cause. The objective of this study was to examine the migration of heavy metals through their concentrations in the upper horizons of a mining soil. Soil profiles were taken between the two piles of mining waste known as tailings 1 and tailings 2, as well as between these tailings and a cyanide tank, all located on the mine site. The soil profiles had four layers or horizons identified by color. The dimensions were 1,5 m deep, 0,90 m wide, and 1,5 m high. The results show that profile 1 was generally the least contaminated with metals. Cadmium (Cd) stands out due to its accumulation in profile 2 (74,07 mg/kg). Arsenic (As) has very low levels in all profiles. It is practically zero in profiles 1 and 2, while a low average value of 0,33 mg/kg is observed in profile 3. Chromium (Cr) concentrations are high in all three profiles, with 87,62 mg/kg in profile 1, 134,09 mg/kg in pit 2, and 133,88 mg/kg in profile 3. Zinc (Zn) levels are very low in all profiles, with a measurable value only in profile 2 (0,09 mg/kg).