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Vol.8, Issue 3; May - June 2023; 

ISSN: 2837-2964 

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9 | A c a d e m i c  J o u r n a l  o f  S c i e n c e ,  E n g i n e e r i n g  a n d  T e c h n o l o g y  

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ENVIRONMENTAL IMPACT OF MINING IN SOUTHWEST 

BURKINA FASO: A COMPREHENSIVE ANALYSIS 

 

Marie-Claire Diarra 

École Nationale Supérieure Université Ouagadougou Canada 

 

ABSTRACT: The intensification of mining activities in Burkina Faso, driven by increased global 

demand for minerals and metals, particularly gold, has raised significant economic prospects for the 

nation. This transformation from a traditionally agrarian economy to a burgeoning mining hub has 

positioned Burkina Faso among the leading gold-producing countries in Africa. This transition is 

marked by the operation of seven active gold mines within the country, ushering in newfound 

opportunities and challenges. 

One notable player in this landscape is the Poura Gold mine, historically the pioneer industrial gold 

mine in Burkina Faso. This mine, managed by the state-owned mining company SOREMIB from 1985 

to 1999, played a pivotal role in shaping the country's mining sector. During its operational years, Poura 

Gold mine contributed significantly, yielding approximately 15 tons of gold. 

In 2012, an American mining company, Newmont, reopened the Poura Gold mine, primarily focusing 

on exploration and prospection activities. However, the remnants of the earlier mining era (1985-1999) 

still linger, manifesting as substantial volumes of mine wastes accumulated at the site. 

This study delves into the evolving dynamics of Burkina Faso's mining landscape, with a particular 

focus on the Poura Gold mine's historical significance and its implications for the present and future of 

mining in the region. It explores the environmental and socioeconomic ramifications of mining activities 

in Burkina Faso, shedding light on the challenges and opportunities that come with this transition. 

 

Keywords: Burkina Faso, mining, Poura Gold mine, gold production, environmental impact. 

  

 

INTRODUCTION   

Due to the high mineral and metal demand of emerging economies such as India and China, the prices of 

these commodities have increased on the international market, leading to intensive mining worldwide. 

Burkina Faso, a landlocked country, has been long considered as a least developed backward 

agricultural country that may benefit from the "mining boom". Since 2010, the country has become the 

fourth largest African gold producing country after South Africa, Ghana and Mali. Nowadays Burkina 

Faso has seven active gold mines (Taparko, Essakane, Mana, Youga, Inata, Kalsaka, Sabcé).  

The Poura Gold mine (Figure 1) was the first industrial gold mine of the country. The mine was 

operated from 1985 to 1999 by the state owned mining company "Société de Recherches Minières du 

Burkina Faso (SOREMIB)". During this period, Poura Gold mine produced approximately 15 tons of 

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gold. In 2012 the mine was reopened by Newmont, an American mining company, but the activities are 

currently limited to exploration and prospection. The previous mining (i.e., 1985-1999) has generated 

several tons of mine wastes which are still piled up on the site.   

These mine wastes consist of overburden, waste rock dumps, tailings and usually various sulfide and 

iron minerals. In the nature the interaction between these minerals and oxygen and/or water lead to their 

oxidation, a process known as acid rock drainage (ARD). However, an exacerbated ARD through 

mining is known as acid mine drainage (AMD).   

AMD is characterized (Kawatra and Natarajan, 2001) by high acidity (low pH) and high concentrations 

of sulfate and metals and metalloids such as iron (Fe), manganese (Mn), aluminum (Al), zinc (Zn), 

copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd) and arsenic (As). As a result, AMD represents, by far, 

the most serious threat to the ecosystem adjacent to mining sites. Thus, AMD acidifies the receiving 

environment through a release of sulfuric acid, and also maintains in solution highly reactive and toxic 

metals (US-EPA, 2000; Naicher 2003; Galvez-Cloutier and Lefrancois 2005). Thus, AMD enhances the 

mobility and bioavailability of potentially toxic metals in the ecosystem.   

The main metals released into the environment due to mining are: Fe, Mn, Pb, Zn, Cd, Cr and Ni. 

Increased solubilization of these metals following AMD generation can enter food web, and pose serious 

threats to human health through consumption, for example, of contaminated seafood. In humans, the 

metals are stored in most soft tissues, particularly the liver and kidneys as well as in the bone, Collon 

(2003). The ingested metals are therefore bioaccumulative and non-biodegradable in human body, and 

thus highly toxic even at very low doses (trace amounts).  

The aim of this paper is to assess the spread of potentially harmful elements (PHE), e.g. heavy metals 

associated to mine wastes and tailings, and its impacts on the environment.   

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Figure 1: Geological map of Burkina Faso with the location of Poura gold mine.  

Acid Mine Drainage (AMD)  

By definition, acid mine drainage is an effluent produced during mining or after the mine closure which 

physic-chemical characteristics differ from the original water (Collon, 2003).  In the deposits and in 

particular metalliferous deposits, minerals are usually associated with sulfur or iron minerals (pyrite, 

chalcopyrite, arsenopyrite, galena, sphalerite, pyrrothite, covelite). Consequently, these sulfide minerals 

are found in tailings or waste rock piles. Exposure of tailings to air and water leads to sulfate and iron 

oxidation and production of acid mine drainage known as AMD. The kinetics of this oxidation reaction 

is enhanced in the presence of thiobacillus  ferrooxidan bacteria, that can speed up the reaction rate 

about 105 time compared to abiotic reaction.   

The acidification will impact the release of metals from various minerals.  An orange-brown color of 

insoluble Fe (OH)3 usually characterizes this acidic drainage.  

Assuming the presence of pyrite in tailings (Kleinman et al., 1981; Aubertin et al., 2002a; Bussière et 

al., 2005), interaction between tailing seeping or highly acidic process waters and a receiving 

environment (e.g., surface water) with  a pH close to neutral (5<pH<7), oxygen will directly oxidize 

pyrite as illustrated in reaction 1.  

FeS2 + 7/2O2 + H2O → Fe2+ + 2SO4
2- + 2H+            [1]  

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Ferrous iron, released from the oxidation of pyrites, can be oxidized to ferric iron according to the 

following reaction:  

Fe2+ + 1/4O2 + H+ → Fe3+ + 1/2H2O              [2]  

At relatively high pH (pH> 4), the ferric iron precipitates as ferric hydroxide releasing more acid in 

water (reaction 3).  

Fe3+ + 3H2O → Fe(OH)3 + 3H+               [3]  

The ferrous iron can also be precipitated as iron hydroxide and produce acid as shown in reaction 4.  

Fe2+ +1/4O2 + 3/2H2O → FeOOH + 2H+             [4]  

When the pH is sufficiently low (pH <4), ferric iron remains in solution, and thus playing the role of a 

highly reactive oxidant (the so-called indirect reaction). The indirect oxidation of pyrite produces more 

protons, and thus exacerbates acidification of the receiving environment (reaction 5).    

FeS2 + 14Fe3+ + 8H2O → 15Fe2+ + 2SO42- + 16H+          [5]  

The overall pyrite oxidation reaction can be expressed as follows:  

FeS2 +15/4O2 + 7/2H2O → Fe (OH)3 + 2H2SO4          [6]  

These equations show that the oxidation of one mole of pyrite produces two moles of sulfuric acid in the 

environment.  

METHODOLOGY   

Samples of surface water, groundwater (hand-pumped boreholes and wells), soil and mine wastes were 

collected at Poura old gold mine.Water concerned surface water and groundwater to assess their 

chemical parameters. The pH and water temperature have been measured in the field; geographic 

coordinates of sampling site have been recorded. For ground water, the depth (of the well) is recorded.  

Each sample of mine wastes and soil is a composite of three sub-samples collected from sampling sites 

located at the distance of 10-20 m from each other. About, 3 kg have been dried, sieved and 

homogenized. The < 2mm fraction (about 5g), have been taken for analysis.  

All samples (water, mine wastes, and soil) were shipped to Johannesburg (South Africa) to the 

laboratory "Acmelabs" for analysis.  

Water samples have been the subject of the determination of F, pH, conductivity, alkalinity and Hg.  

Samples of mine waste, and soil were subjected to aqua regia digestion and a full suite of 36 elements 

have been analyzed.  

RESULTS   

Sampling  

All collected samples are reported in Figure 2. A total of 10 groundwater samples, 14 of surface water, 

16 of soil and 11 of mine wastes were collected.  

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Figure 2: Location of sampling sites on the satellite map (Google imaging © 2014)  

Groundwater and surface water  

Results of chemical analyses of the groundwater and surface water are given in Tables 1a and 1b.  

Table 1a: Chemical analyses of groundwater  

   Physical parameters    Miscellaneous inorganics (mg/l)   

Sample  Depth 

(m)  

Temperature 

 Conductivity  

(°C)  (µS/cm)  

pH  Fluoride  Alkalinity  Bicarbonate 

 Carbonate  

Total  HCO3  CO3  

CaCO3  

Hydroxide 

OH  

GW1  *HPB  31.50  340  8.45  0.190  189  221  4.82  <0.50  

GW2  *HPB  32.30  239  8.35  0.120  133  158  2.22  <0.50  

GW3  25  23.40  157  8.02  0.096  78.6  95.9  <0.50  <0.50  

GW4  *HPB  30.70  357  8.39  0.250  197  232  4.03  <0.50  

GW5  30  28.60  169  7.73  0.098  58.9  71.9  <0.50  <0.50  

GW6  *HPB  30.80  365  8.37  0.240  155  184  2.87  <0.50  

GW7  *HPB  30.80  339  8.38  0.200  145  170  3.04  <0.50  

GW8  *HPB  31.00  455  8.32  0.063  193  230  2.42  <0.50  

GW9  10  29.40  153  7.49  0.045  17.8  21.7  <0.50  <0.50  

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GW10  *HPB  28.40  456  8.67  0.130  244  271  13.10  <0.50  

*HPB: Hand-pumped borehole  

  

  

  

 Table 1b: Chemical analyses of surface water  

 Physical  parameters      Miscellaneous 

inorganics 

(mg/l)   

   

Sample   Temperature  

(°C)   

Conductivity  

(µS/cm)   

pH   Fluoride   Alkalinity  

Total 

CaCO3   

Bicarbonate   

HCO3   

Carbonate   

CO3   

Hydroxide  

OH   

SW1   28.3   234   8.03   0.076   60.70   74.10   <0.50   <0.50   

SW2   29.1   233   7.88   0.065   61.80   75.40   <0.50   <0.50   

SW3   29.0   454   8.33   0.380   165   197   2.12   <0.50   

SW4   27.6   60.4   6.61   0.064   8.29   10.10   <0.50   <0.50   

SW5   34.2   146   8.07   0.110   70.00   85.40   <0.50   <0.50   

SW6   28.3   45.6   7.44   0.058   16.30   19.80   <0.50   <0.50   

SW7   32.2   45.7   7.54   0.072   16.70   20.30   <0.50   <0.50   

SW8   29.3   225   7.95   0.059   59.50   72.60   <0.50   <0.50   

SW9   28.6   287   8.13   0.670   150   183   <0.50   <0.50   

SW10   27.9   624   8.51   0.400   290   336   8.99   <0.50   

SW11   30.2   112   8.06   0.090   47.10   57.50   <0.50   <0.50   

SW12   27.9   556   8.27   0.160   191   233   <0.50   <0.50   

SW13   34.2   8810   2.23   0.027   <0.50   <0.50   <0.50   <0.50   

SW14   32.2   48.0   7.23   0.076   15.50   18.90   <0.50   <0.50   

Mine wastes and soil   

The contents of some potentially harmful elements are shown in Table 2a and 2b. This table shows for 

arsenic, copper, nickel, lead and zinc relatively much higher contents in the mine wastes than in soils. 

Concentrations in mine wastes are: arsenic (4 to more than 10000 ppm), lead (2 to 1339.6 ppm), zinc (14 

to 604 ppm), copper (7 to 534.8 ppm), cobalt (3 to 40 ppm), chromium (5 to 304 ppm), nickel (3 to 

101.3) and cadmium (0.1 to 5 ppm). These contents in the soil are: arsenic (0.5 to 335.2 ppm), lead (3.8 

to 49 ppm), zinc (7 to 130 ppm), copper (7 to 49.7 ppm), cobalt (4 to 35.8 ppm), and chromium (41 to 

299 ppm), nickel (6 to 133.6 ppm) and cadmium (for the most less than the detection limit).  

Table 2a: Contents of some potentially harmful elements in the mine waste samples  

Element   As   Cd   Co   Cr   Cu   Pb   Zn   Ni   Hg   Fe   

Unit   PPM   PPM   PPM   PPM   PPM   PPM   PPM   PPM   PPM   %   

*LOD   0.5   0.1   0.1   1   0.1   0.1   1   0.1   0.01   0.01   

W1   198.6   <0.1   3.4   5   7.7   21.9   21   5.8   0.24   0.70   

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W2   4.2   <0.1   39.0   87   80.9   2.3   84   68.3   <0.01   7.23   

W3   563.7   0.1   35.6   39   41.6   11.9   69   47.4   0.05   3.37   

W4   44.0   <0.1   4.7   14   17.8   1.3   14   3.2   <0.01   1.50   

W5   4025.5   5.2   38.1   70   534.8   948.0   588   75.0   2.25   5.12   

W6   549.8   <0.1   6.3   18   11.4   10.9   24   10.9   0.04   1.92   

W7   151.5   <0.1   38.5   64   44.3   4.9   42   33.8   0.09   3.75   

W8   141.8   <0.1   19.7   10   26.6   2.6   23   13.8   0.06   1.84   

W9   309.6   1.7   28.7   304   253.8   804.0   604   101.3   0.26   12.88   

W10   >10000.0   0.9   24.4   15   251.3   1339.6   107   60.2   4.08   9.24   

W11   >10000.0   2.8   40.0   24   329.1   1069.8   364   83.3   3.68   10.97   

*LOD: Li mit of detectio n   

  

        

Table 2b: Contents of some potentially harmful elements in the  soil 

sampl es   

   

Element   As   Cd   Co   Cr   Cu   Pb   Zn   Ni   Hg   Fe   

Unit   PPM   PPM   PPM   PPM   PPM   PPM   PPM   PPM   PPM   %   

*LOD   0.5   0.1   0.1   1   0.1   0.1   1   0.1    0.01   

S1   1.3   <0.1   16.3   52   23.7   11.8   28   24.4   
 

2.92   

S2   335.2   0.2   35.8   51   49.7   49.0   130   28.7   1.04   4.36   

S3   9.9   <0.1   16.2   83   29.0   4.4   20   36.6   <0.01   3.37   

S4   7.3   <0.1   25.8   141   27.1   5.6   34   74.6   0.01   3.86   

S5   0.5   <0.1   4.8   25   7.6   6.8   7   6.6   <0.01   1.37   

S6   3.6   <0.1   16.8   67   17.7   4.6   16   36.8   <0.01   2.23   

S7   20.8   <0.1   17.9   55   19.0   4.9   11   11.7   0.02   2.38   

S8   11.5   <0.1   22.0   299   23.8   3.8   21   133.6   0.01   3.63   

S9   64.2   <0.1   24.6   70   31.5   16.2   73   21.4   0.84   4.16   

S10   33.9   <0.1   20.3   50   23.9   4.6   35   25.2   0.05   3.52   

S11   105.6   <0.1   30.7   283   42.0   30.2   47   22.5   1.18   12.89   

S12   4.5   <0.1   16.6   103   18.1   4.8   17   30.8   <0.01   2.55   

S13   19.0   <0.1   18.5   41   18.9   4.9   12   14.8   <0.01   2.17   

S14   5.2   <0.1   14.1   57   11.6   5.6   15   12.1   0.02   2.92   

S15   4.5   <0.1   12.2   43   14.3   4.1   13   16.7   <0.01   2.67   

SNC1   17.7   <0.1   20.0   70   15.7   5.9   13   15.2   <0.01   2.43   

*LOD: Limit of detection  

DISCUSSION   

All samples were collected in August (rainy season), which justifies the relatively high temperatures of 

water samples. Ground water is characterized by a pH close to neutrality (7.49-8.67) and relatively low 

conductivity values compared to the surface water (153-456 µS/cm). The surface water samples SW4 

and SW13 show lower values of pH which are respectively 6.61 and 2.23. Sample SW13 with high 

conductivity (8810 uS / cm) and high acidity (low pH) confirms the presence of AMD resulting from the 

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oxidation of tailings stored there. These values indicate that oxidation is local and very advanced in that 

the pH value is below the minimum 6.5 required for the protection of aquatic life and even below the 

acute toxicity of 5.0 (Berryman et al. 2003). According to the standards in force in Burkina Faso 

guideline values for fluoride are 0.07 to 1.5 mg/l. Concentrations of fluoride are higher in groundwater 

than in surface water. However, these values are consistent with the guideline values.  

The alkalinity values are highly variable from one sample to another, and are higher in groundwater than 

in surface water. The acidification of SW13 is confirmed by its alkalinity which is less than the detection 

limit (0.50 mg /l CaCO3). According to the "Ministère du développement durable, de l’environnement, 

de la faune et des parcs" (MDDEFP, 2013) the sensitivity of a medium to the acidification varies with 

alkalinity: high sensitivity, alkalinity < 10 mg /l CaCO3; mean sensitivity, alkalinity ranges from 10 to 

20 mg /l CaCO3; low sensitivity alkalinity > 20 mg /l CaCO3. The anions HCO3
-, CO3

2- and OH- have 

also been analyzed. Bicarbonate, carbonate and hydroxide form alkalinity, however, natural waters 

usually contain no carbonate or hydroxide.   

The results given in Tables 2a and 2b show that the concentrations of various analyzed elements are 

higher in mine tailings than in soils. This is due to the mineralogy of the host rocks of the 

mineralization. Indeed, at Poura geology comprise mainly volcanic rocks (andesite-dacite), volcano-

sedimentary (tuffs, agglomerates) and detrital sedimentary rocks (pelitic to conglomerate rocks) which 

are intruded by mafic to felsic intrusions (granites gabbroic). Gold is associated with quartz veins whose 

cracks are filled by sulfides: pyrite (FeS), arsenopyrite (FeAsS), sphalerite (ZnS), galena (PbS), 

chalcopyrite (CuFeS). High levels in some soil samples (arsenic: S2, S11; lead: S2 and zinc: S2) would 

come from contamination through leaching, solubilization (due to the decline in pH) and migration of 

elements from tailings stockpiles. This means enrichment for these elements. Sampling site S2 is the 

most contaminated and mainly by arsenic, lead and zinc.  

For soils there are no guideline values from Burkina Faso. But according to Canadian soil quality 

guidelines for the protection of environmental and human health (Canada, ATSDR, 2005), and taking 

into account the fact that these soils used for agriculture, some sites are polluted by arsenic, chromium, 

copper, lead, nickel and zinc.  

To assess the level of contamination, the index of geo-accumulation (Igeo), (Muller, 1969; Krzysztof et 

al, 2003) was calculated for soil samples and mine wastes, to assess the presence and levels of 

contamination (Table 3a, 3b).   

Igeo   

Cm = concentration of a given element in the tested soil;  

BV = concentration of the element in the Earth’s crust (background value); the background values after 

Levinson (1974) after Lar et al. (2003).  

1.5 = a constant accounting for fluctuations in the content of a given substance in the environment. The 

negative of geo-accumulation indexes for some elements indicates the absence of contamination.  

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The use of the index of geo-accumulation is based on seven descriptive classes for increasing Igeo 

values shown in Table 4.   

Table 3a: Igeo values for some elements in the soil  

Element  Igeo   As   

  

Co   

  

Cr   

  

Cu   

  

Pb   

  

Zn   

  

Ni   

  

S1   -0.24   1.04   0.84   1.20   0.90   -0.03   0.51   

S2   2.17   1.38   0.83   1.52   1.51   0.04   0.58   

S3   0.64   1.03   1.04   1.29   0.47   -0.18   0.69   

S4   0.51   1.24   1.27   1.26   0.57   0.05   1.00   

S5   -0.65   0.51   0.52   0.70   0.66   -0.63   -0.06   

S6   0.20   1.05   0.95   1.07   0.49   -0.27   0.69   

S7   0.97   1.08   0.87   1.10   0.51   -0.44   0.19   

S8   0.71   1.17   1.60   1.20   0.40   -0.15   1.25   

S9   1.46   1.21   0.97   1.32   1.03   0.39   0.46   

S10   1.18   1.13   0.82   1.20   0.49   0.07   0.53   

S11   1.67   1.31   1.58   1.45   1.30   0.19   0.48   

S12   0.30   1.04   1.14   1.08   0.51   -0.25   0.61   

S13   0.93   1.09   0.74   1.10   0.51   -0.40   0.30   

S14   0.36   0.97   0.88   0.89   0.57   -0.30   0.21   

S15   0.30   0.91   0.76   0.98   0.44   -0.36   0.35   

SNC1   0.90   1.12   0.97   1.02   0.59   -0.36   0.31   

  

Table 3b: Igeo 

v 

alues for 

some  

 elements in th e mine 

wastes   

    

Element  As   

Igeo     

Co   

  

Cr   

  

Cu   

  

Pb   

  

Zn   

  

Ni   

  

W1  1.95   0.36   -0.18   0.71   1.16   -0.15   -0.11   

W2  0.27   1.41   1.06   1.73   0.19   0.45   0.96   

W3  2.40   1.38   0.72   1.44   0.90   0.36   0.80   

W4  1.29   0.50   0.27   1.07   -0.06   -0.33   -0.37   

W5  3.25   1.40   0.97   2.55   2.80   1.29   1.00   

W6  2.39   0.62   0.38   0.88   0.86   -0.10   0.16   

W7  1.83   1.41   0.93   1.47   0.51   0.15   0.65   

W8  1.80   1.12   0.12   1.25   0.24   -0.12   0.26   

W9  2.14   1.28   1.61   2.23   2.73   1.30   1.13   

W10  >3.65   1.21   0.30   2.22   2.95   0.55   0.90   

W11  >3.65   1.43   0.51   2.34   2.85   1.08   -0.11   

  

  

Table 4: Igeo classes with 

ct to soil 

quality   

    

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res pe 

Igeo value  Igeo class   Designation of soil 

quality   

  

> 5  6   Extremely contaminated     

4-5  5   Strongly to extremely contaminated    

3-4  4   Strongly contaminated    

2-3  3   Moderately to strongly contaminated    

1-2  2   Moderately contaminated    

0-1  1   Uncontaminated to moderately contaminated    

0  0   Uncontaminated    

According to these classes, soils are uncontaminated to moderately contaminated (class 1) by arsenic, 

cobalt, chromium, copper, lead, zinc and nickel. They are moderately contaminated (class 2) by arsenic, 

cobalt, chromium, copper, lead and nickel. The Igeo class 3, i.e.  

moderately to strongly contaminated sites concerns only arsenic.  

  

Concerning mine wastes, Igeo classes 1 and 2, i.e. respectively uncontaminated to moderately 

contaminated and moderately contaminated concern both element in table 4 (arsenic, cobalt, chromium, 

copper, lead, zinc and nickel). The highest degrees of contamination are caused by arsenic, copper and 

lead (class 3: moderately to strongly contaminated sites) and by arsenic (class 4: strongly contaminated 

sites). So, in soils and mine wastes, the most harmful element is arsenic. Arsenic, copper and lead are 

the main constituents of sulfides (arsenopyrite: FeAsS, chalcopyrite: CuFeS, galena: PbS) encountered 

in the mineralized host rocks at Poura. This explains their high concentrations in mine wastes that 

resulted from the ore treatment or waste rocks.  

According to Smedley et al (2007), the source of arsenic in Burkina Faso, is likely to be the oxidized 

sulfide minerals and secondary iron oxides in the mineralized zones. For these authors, high-As 

groundwater observed derive from zones of gold mineralization in Birimian (Lower Proterozoic) 

volcano-sedimentary rocks, the gold occurring in vein structures along with quartz and altered sulfide 

minerals (pyrite, chalcopyrite, arsenopyrite). This is consistent with the assumption mentioned above. 

Therefore, the high arsenic concentrations in soils and groundwater would be the host rocks of gold 

mineralization. At Poura, soil contamination in arsenic would come from mine wastes stockpiles stored 

for many years.  

Indeed, in the problems of environmental pollution, the main parameters to consider are the source, 

intensity, extent and vulnerability. If the source (oxidation of mine waste or AMD), the intensity (Igeo 

and Igeo classes) and extent (contaminated sites) can be established, it is not the same the vulnerability 

without analyzes e.g. of plants, crops, blood, urine or hair.  

So, concerning vulnerability, despite the lack of analysis of plants and crops, heavy metals released into 

the environment through the oxidation of mine wastes can be absorbed by plants. Indeed, several studies 

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e.g. Álvarez et al (2003), Huang (2007), Zhang et al (2009), Lar et al (2013), Park and Choi (2013), 

Kalagbor and Diri (2014) have shown that plants can absorb heavy metals that will be eventually 

encountered in their fruits, leaves and tubers. In addition, heavy metals and potentially harmful element 

released by the oxidation of mine wastes can be transported in the Mouhoun River which is the main 

river in the region. The populations will be contaminated as a result in the consumption of fishes that 

have ingested these different toxic elements.  

CONCLUSIONS  

This study shows that mine wastes stockpiles at Poura, are oxidized in some places, due to their 

exposure during several years to water and atmospheric agents. This oxidation is the source of acidic pH 

of surface water or acidic effluents known as acid mine drainage (AMD). This acid mine drainage 

results in the solubilization of potentially harmful elements (arsenic, cobalt, chromium, copper, lead, 

zinc and nickel) that are subsequently released into the environment.   

The index of geo-accumulation (Igeo) and the descriptive classes for increasing Igeo values indicate that 

arsenic, copper and lead are the most harmful elements. The soil is moderately contaminated (class 2) by 

arsenic, cobalt, chromium, copper, lead and nickel, then moderately to strongly contaminated (class 3) 

by arsenic. For mine wastes, moderately contaminated sites (class 2) are due to arsenic, cobalt, 

chromium, copper, lead, zinc and nickel; moderately to strongly contaminated (class 3) by arsenic 

copper and lead; strongly contaminated (class 4) by arsenic which appears to be the most polluting 

element.   

The source of these elements that cause the phenomenon of contamination would be sulfides and other 

metallic minerals which constitute the host rocks of the mineralization and are encountered in mine 

wastes.  

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ISSN: 2837-2964 

Impact Factor: 6.67 

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