Evaluation of Environmental Aspects of Artisanal Gold Mining at the Tchaga Site in the Batha Province (in the East of Chad)

In the east of Chad, precisely in Tchaga, gold is mined in an artisanal manner. This gold panning activity contributes to the income of rural populations. However, this activity uses chemical processes involving mercury and cyanide which cause impacts on surface water and groundwater. In a context of favorable gold prices, the number of artisanal mines is increasing and it is interesting to dwell on the question, also understanding that few studies have been carried out, until now, on gold panning in relationship with environmental aspects. The present study then consists of evaluating the impacts of gold panning on the environment on the Tchaga sites. To understand the phenomenon and quantify it, it was necessary to carry out a combinatorial analysis of the surface and underground waters of the study area. The results obtained indicate that the negative impacts of gold panning on soils range from moderate to high with a reduction in arable land. The methodology used consists of water sampling, measuring physical parameters and using methods to determine the concentrations of cations and anions. After analyzing the results of ETM analysis in the water, it appears that the water is not very loaded with ETM and heavy metals. The water contains average concentrations (0.001 mg/l in As, 0.003 mg/l in Pb and 0.001 mg/l in Zn or even zero for mercury) which are generally lower than WHO standards. In surface waters, the concentration of Hg is 0.000 mg/l and that of Zn is 0.002 mg/l. Values below the limit values set by the WHO do not indicate any presence of apparent contamination by gold panning activities at least for the moment. In groundwater, the mercury concentration is zero compared to the limit value set by the WHO, this is due either to the quantity of the product, the sampling, or the time of contamination. On the other hand, zinc has a low value compared to the limit value set by the drinking water standards in Chad. While the arsenic concentration (0.002 mg/l) does not reach the limit value set by the WHO (0.01 mg/l).