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Metal Contamination of an Underground Gold Picking Zone in the Department of Djekanou, Cote D’Ivoire

2021; Science Publishing Group; Volume: 9; Issue: 1 Linguagem: Inglês

10.11648/j.ijema.20210901.11

2328-7659

Ouattara Bakary, Aka Ané Maurice, Yao Kouakou Alphonse, Seka Yapoga Jean, Gnagne Essoh Jean Eudes Yves, Yapo Ossey Bernard,

Mining and Resource Management

Illegal gold mining has developed in recent years in the department of Djékanou with the rising cost of gold on the world market, due to the slump in local agricultural products and the unemployment of young people of working age. It has become an essential activity along with agriculture and farming in rural areas. It is an effective way to fight poverty. However, this practice is likely to cause significant environmental damage. Thus, to assess the environmental quality of this region prone to gold mining activity, the determination of the level of metallic contamination of environmental matrices (soils and sediments) was carried out. Four (4) soil and sediment sampling campaigns took place in dry and rainy seasons on the illegal gold mining site and near the dam, all located at about 685 m from Yobouékro, on the gold washing site of Taffissou at 3,425 m from Djékanou and at Groudji in the department of Djékanou. The sediment sampling was carried out by Strahler's method, while that of the soils was taken at random over the extent of the gold washing sites. The total concentrations of metals in the different matrices were determined by atomic absorption spectrophotometry (AAS). The analytical results show that the metal contents are lower than the natural content of each element in the earth's crust (UCC). Gold mining activities are not currently a source of metallic contamination of the environment. Also, the contamination factors recorded from the concentrations of metals are all less than 1, indicating low contamination of sediments and soils by trace metal elements despite intense gold mining activity. Notwithstanding, the evaluation of the environmental quality from the concentrations of the metals Cd, Co, Cr, Hg and Pb compared to the American guide values SQGs (TEC and PEC), it is noted that the receiving environment is contaminated only by mercury, cadmium and cyanide; the values of the other parameters studied being lower than the guide values. The two matrices mentioned above were also assayed with cyanide and the results revealed that the sites of Groudji and Taffissou are contaminated.