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Vulnerability of groundwater to pollution at the Dabiss bauxite mining area, Boké Prefecture, Republic of Guinea

Vulnerability of groundwater to pollution at the Dabiss bauxite mining area, Boké Prefecture,... GEOLOGY, ECOLOGY, AND LANDSCAPES INWASCON https://doi.org/10.1080/24749508.2022.2138012 RESEARCH ARTICLE Vulnerability of groundwater to pollution at the Dabiss bauxite mining area, Boké Prefecture, Republic of Guinea a,b a,b a,b c,d Alpha Mamoudou Diallo , Ahmed Amara Konaté , Fassidy Oularé and Muhammad Zaheer Laboratoire de Recherche Appliquée en Géoscience et Environnement, Institut Supérieur des Mines et Géologie de Boké, Boké, Republic of Guinea; Centre Emergent Africain Mines et Société, Institut Supérieur des Mines et Géologie de Boké, Boké, Republic of Guinea; c d Department of Earth & Environmental Sciences, Hazara University, Mansehra, Pakistan; Department of Civil Engineering and Mechanics, Lanzhou University, Chengguan District, Lanzhou, Gansu, China ABSTRACT ARTICLE HISTORY Received 23 February 2022 Boké Prefecture has become a popular mining location, with various extractive corporations Accepted 13 October 2022 competing for bauxite extraction. Water samples were obtained from eighteen water wells across the Dabiss study area. All Physico-chemical parameters and major ions of groundwater KEYWORDS were compared with World Health Organization (WHO) standard. Furthermore, using Excel and Groundwater vulnerability; the Inverse Distance Weighted (IDW) interpolation technique in Arc GIS software, bi-plots of groundwater pollution; Physico-chemical parameters and spatial variations of water quality maps were generated Dabiss bauxite mining; respectively. A vulnerability study of groundwater pollution by mining activities was conducted Prefecture of Boké; Republic of Guinea by applying the standard DRASTIC method. It was found that the drinking water samples of the study areas were usually within the water quality standards of WHO. According to physico- chemical analysis, most of the groundwater in the study area appears to be acidic. An equilibrium was set up in the aquifer between the chemical composition of the water and that of the rocks. The DRASTIC method enabled us to show a low vulnerability index to groundwater pollution. The results of this study could prevent diseases linked to the consump- tion of water contaminated and improve the quality of life of the population and will serve as a reference document in other mining areas. Introduction drinking water quality and their resources (Shahab Water is associated with approximately every type of et al., 2018). In recent years, the negative impact of mining company, whether as groundwater, surface bauxite mining on the environment has been stated by water, or wastewater, and consequently, there is an several authors such as (Chen et al., 2022; Keita & important need to evaluate water quality and quantity Traore, 2020; Lad & Samant, 2012; Rao et al., 2016; conditions in all phases of mining: exploration, pro- Souare, 2019). duction, and decommissioning. Changes in water Preserving the quality of groundwater is most quality can lead to many types of impacts and the important because it may lead to a danger for con- mining company unfortunately creates various such sumption (Ewodo Mboudou et al., 2016), and people problems. One of the standard impacts comes from who use using this contaminated groundwater as groundwater for domestic use. Contaminated water drinking water is at risk of illness in the future may affect human health, animals, and plants. Metal (Bakouan et al., 2017). Consequently, water, which is mining can be linked with some environmental degra- considered a source of life, may become a source of dation even though being a vital source for mineral disease within a large population, due to the mining exploration. This can be associated with the impact on activities which are in full expansion, with the indus- water due to water acidification and the impact of trial revolution. Based on the various challenges of heavy metals (Affandi et al., 2018). Bauxite mining pollution, conformation with drinking water quality activities are a main open cast mining interest that standards is a major concern. reflects substantial adverse effects on the environment Lack of groundwater vulnerability studies in such as dust pollution and negative effects on water mining areas, as well as inadequate infrastructure, resources (Kusin et al., 2017). In bauxite mining areas contributes to the development of waterborne diseases the major sources of water pollution are Al and Fe. (malaria, yellow fever, typhoid fever, cholera, filariasis, Further that when the natural ecosystem is disturbed meningitis, hepatitis A and B, and diarrhea), which are and excavated then other pollutants such as As, Ni, currently responsible for the deaths of more than Hg, Cd, Pb, and other heavy metals may also affect 2.2 million people worldwide each year (Moe & CONTACT Ahmed Amara Konaté konate77@yahoo.fr Laboratoire de Recherche Appliquée en Géoscience et Environnement, Institut Supérieur des Mines et Géologie de Boké, BP 84, Baralandé, Boké, Republic of Guinea © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the International Water, Air & Soil Conservation Society(INWASCON). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 2 A. M. DIALLO ET AL. Rheingans, 2006). Compared to the natural environ- Guinea bauxite reserves are likely at over 40 billion ment, the mining area has specific hydrology which tons and out of them, 23 billion tons are situated in the must be considered when estimating the vulnerability Boké region (Keita & Traore, 2020). Bauxite mining of groundwater; and also, when evaluating the risks of and alumina production offer about 80% of Guinea’s contamination that the exploitation of bauxite has on foreign exchange (Keita & Traore, 2020). Guinea aquifer resources (Ducommun, 2010). The notion of bauxite now makes up a huge amount of the Al used vulnerability of groundwater to pollution is a prime across the world in aero plane, car parts, and consu- concern with hydrogeological parameters which mer products like tin foil and beverage cans. With include lithology, depth to groundwater level, geo- numerous more international companies preparing chemistry, soil, and geomorphology of the investigated to begin exports from Guinea which has the world’s area (Mali et al., 2020). leading bauxite deposits, may soon turn out to be the The DRASTIC method of vulnerability assessment, leading global producer (Knierzinger, 2014). of the parametric type, was developed in the 1980s by The Prefecture of Boké became a mining site where the US Environmental Protection Agency (Batchi several mining companies are competing for bauxite et al., 2017). Because of its practical and intuitive (Dresse et al., 2021). Open-pit mining often consists of approach, the DRASTIC method has been used to the removal of natively vegetated areas and is so one of estimate the vulnerability of groundwater resources. the most environmentally destructive types of mining, For example, (Ducommun, 2010; Singh et al., 2010; especially within tropical forests. All the sub- Xin et al., 2011; Neha Gupta, 2014; Shahab et al., 2018; prefectures of Boké with a bauxite plateau are affected, Machiwal et al., 2018; He et al., 2018; Barbulescu, particularly Dabiss (Knierzinger, 2014). 2020; Mali et al., 2020; Nurroh, 2020; Satouh et al., Dabiss is a sub-prefecture in the Boké Prefecture in 2021; Taazzouzte et al., 2021). The DRASTIC method the Boké Region of western Guinea and it had is still an extremely simple and quick method to use a population of31947people (Institut National de la and perfectly fulfills its role as a preliminary approach Statistique (INS), 2016). Figure 1 shows the presenta- for estimating the vulnerability of an aquifer. This tion of Dabiss. Dabiss has a total area of bare plateau of makes it a practical tool, as it requires little hydrogeo- 5580.860 ha or 55,808,600 m (Knierzinger, 2014) and logical data, but by no means sufficient for the protec- mining activities began in 2015 by the Boké Mining tion of groundwater resources (Barbulescu, 2020). Company (SMB). SMB is a group project that includes Groundwater pollution is now and will increasingly a Chinese company that is the largest aluminum pro- be a major concern for various water specialists in ducer in the world. The SMB group has experienced developing countries. tremendous growth since its creation in 2015; it is now The global bauxite resource has been estimated at the country’s main exporter (Human Rights Watch, more than 70 billion tons, with the largest concentra- 2018). There is an intense need to study the quality of tion in Guinea, where an estimated 25 billion tons of water in and around mining areas to help prevent bauxite might be present (Lee et al., 2017). Guinea is disease and improve the quality of life (Bakouan endowed with extraordinarily rich but underexploited et al.,). subsoil. However, over the past decade, foreign invest- In our study area, mining is carried out in ments in the mining sector increased thanks to open pits, where the vegetation cover is comple- the second wave of liberalization of mining codes tely stripped before reaching the ore. This process (Campbell & Hatcher, 2019). This increased Guinean leads to a vulnerability of the groundwater aqui- production, especially of bauxite. The country thus fers, which helps the pollution of water resources. becomes the second largest producer of this mineral It should be noted that several studies have been in the world, just behind Australia (Frost-Killian et al., conducted on the environmental impact (Dresse 2016). et al., 2021; Keita & Traore, 2020; Souare, 2019) The contribution of the mining sector to Guinea’s and very few on the search for groundwater for GDP rose from 4.2% in 2010 to 7% in 2020 (Frost- drinking water supply (Knierzinger, 2014). Killian et al., 2016). Indeed, the Guinean economy was Despite this work on groundwater in the study supported since independence by the mining sector, area, to our knowledge, no groundwater vulner- which in 2018 represented more than 98% of export ability study in the Dabiss area was conducted. revenues (Soumah, 2009). Mining development The overall aim is to study the impact of bauxite should not only see the short-term economic benefits mining on groundwater in the Dabiss area. but go beyond, by considering all the social and envir- Firstly, to analyze the Physico-chemical para- onmental issues, which were medium to long term. It meters and major elements of groundwater; sec- is widely shown that mines affect the agricultural and ondly, to establish a groundwater vulnerability livestock space of local populations, water resources, map to obtain a solution for protecting aquifers soil fertility, air quality, etc (Kitula, 2006). in the study area. GEOLOGY, ECOLOGY, AND LANDSCAPES 3 Figure 1. The presentation of sub-prefecture of dabiss. This research could prevent diseases linked to the c) Devonian Suite Faro (Dfr): Devonian deposits consumption of water contaminated by bauxite outcrop in the east and northeast of the study area. mining and improve the quality of life of the popula- They are represented by aleurolites, argillites, and tion and will serve as a reference document in other sandstones; brachiopod fossils are found. The end of mining areas. this period was affected by Mesozoic dolerite intrusions. d) The Cenozoic formations: they are essentially Geology, geomorphology, and hydrogeology of represented by undifferentiated deposits (clayey the site sands and alluvial sandy silts with gravels, pebbles, and gravels, clayey sands with angular arena and The sub-prefecture of Dabiss is in the north-west of pebbles, deluvial-proluvial, marine silts, clays, and the Prefecture of Boké, between 11°00’ and 11°50’ sands. Figure 2 shows the geological map of the North latitude, 14°50’ and 14°75’ West longitude. It study area. is situated 37 km from the town of Boké, as the crow Tectonically, the study area is part of the sedimen- flies. According to Mamedov et al. (2010), Dabiss tary cover of the West African Craton and occupies consists of Paleozoic formations, which are repre- the entire part of the Bowé synclise. It has been sented by the Ordovician Pita suite (Opt), the affected by a fault that runs from southwest to north- Silurian Télemilé suite (Stl), and the Devonian Faro east (Bah, 2013). suite (Dfr). From a geomorphological point of view, the study a) Ordovician-Suite Pita (Opt): Ordovician deposits area belongs to two major geomorphological zones outcrop in the southwest of the Dabiss sub-prefecture (the coastal plain and the Fouta Djallon massif; in the coastal plain. They are represented by quartz Samozvantsev & Diallo, 1976): and oligomeric sandstones, often with oblique bed- a) The coastal plain: this occupies the western part ding, aleurolite lenses, gravelites and conglomerates. of the territory and constitutes a relatively flat surface. In the Republic of Guinea this suite is subdivided into It slopes slightly to the west and southwest and is five (5) sub-suites: Opt1; Opt2; Opt3; Opt4 and Opt5. formed by the valleys of the Cogon-Tinguilinta and The difference between the sub-suites is due to the their tributaries. granulometry. The grain size decreases from Opt1 to b) The Fouta Djallon massif: it forms a plateau Opt5. separated by the river valleys of Cogon and Tinguilinta b) The Silurian Suite Télemilé (Stl): Silurian depos- From a hydrogeological point of view, Dabiss pre- its outcrop in the southeast, center, and northwest of sents several types of aquifers. According to their the study area. They are represented by argillites and mode of recharge, it can be found (Togba, 1977): aleurolites. They have graptolite fossils. 4 A. M. DIALLO ET AL. Figure 2. Geological map of the study area. - The sandy-clay aquifers, allumino-feriginous, are Material and methods linked to the alteration crust. Field data collection - Silt-sand, sandy, and gravelly aquifers, linked to alluvial deposits. Sampling was carried out at eighteen (18) water - Dolerite aquifers and fissured gabbro-dolerite points in October 2018 across the villages. These aquifers linked to magmatic intrusions. drinking water samples were carried out and Figure 3. The localization of the study zone. (a) Localization of Dabiss area in Guinea; (b) localization of the study area in the Sub- Prefecture of Dabiss; (c) Presentation of the study area. GEOLOGY, ECOLOGY, AND LANDSCAPES 5 Table 1. Inventory of groundwater sampling points in the Dabiss study area. Geographical coordinates Well identification Villages X Y Well depth (m) PF1 Kaferé 14° 26’ 00,9” 11° 08’ 07,8” 73,07 PF2 Sambala 14° 27’ 31,6” 11° 04’ 55,3” 89,95 PF3 Kamsenhet 14° 26’ 18,7” 11° 04’ 19,9” 78,82 PF4 Togmaye 14° 31’ 31,4” 11° 02’ 22,4” 61,82 PF5 Kalounka Missidé 14° 30’ 04,3” 11° 06ʹ06,4” 72,91 PF6 Kamandé 14° 30’ 13,3” 11° 10’ 46,9” 67,23 PF7 Dikawé 14° 31’ 47,5” 11° 09’ 43,7” 63,46 PF8 Dabiss F2 AEP 14° 32’ 20,9” 11° 11’ 33,5” 50,55 PF9 Dapopo 14° 33’ 25,4” 11° 12’ 38,8” 84,20 PF10 Dabon 14° 35’ 53,3” 11° 06’ 33,4” 56,15 PF11 Thiankoun foulbé 14° 38’ 36,3” 11° 15’ 23,8” 61,90 PF12 Yenguekounia 14° 36’ 11,3” 11° 11’ 40,8” 56,10 PF13 Tomboya 14° 36’ 53,2” 11° 09’ 57,9” 73,06 PF14 Tambindjé 14° 33’ 16,1” 11° 14’ 09,1” 84,40 PF15 Wenseng II 14° 34’ 44,0” 11° 16’ 36,1” 67,49 PF16 Hafia 14° 36’ 31,0” 11° 17’ 17,2” 56,23 PF17 Mangodjé 14° 40’ 01,6” 11° 21’ 55,0” 56,20 PF18 Silibonty 14° 37’ 18,5” 11° 18’ 24,8” 56,29 analyzed in the laboratory by the National Water ID ¼ Dp� Dcþ Rp� Rcþ Ap� Acþ Sp� Sc Point Service (SNAPE). Figure 3 shows the locali- þTp� Tcþ Ip� Icþ Cp� Cc zation of the study zone. To facilitate data hand- (1) ling, a sample number was assigned to each sampling point as can be seen in Table 1. The Where Physico-chemical parameters (pH, temperature, D water depth, R effective recharge, A aquifer type, electrical conductivity, turbidity) were measured S soil type, T topography, I vadose zone, and in situ using a multi-parameter probe. Dissolved C hydraulic conductivity of the aquifer medium (Let oxygen was determined by the Winkler method D, R, A, S, T, I and C be the seven parameters of the (Rodier et al., 2009). The water levels were mea- DRASTIC method: p being the weight of the para- sured using a piezometric probe. The chemical meter and c the associated score). The results obtained analyzes of the major elements (cations and anions) from the DRASTIC index are presented in Table 2. were conducted by ion chromatography. Results Reference method A reference method is an official method recognized Physico-chemical parameters by international bodies that gives the most accurate Hydrogen potential (pH) result such as the closest to the true value of the The pH is one of the most significant parameters in concentration of a constituent under analysis. The acid-base geochemical water quality parameters. It is reference method usually gives the most accurate truly a measure of the relative quantity of free hydro- results, by composition with other methods of analysis gen and hydroxyl ions in the water. Water that holds of the constituent. In this study, we used the reference more free hydrogen ions is acidic and more free method. The results of the Physico-chemical analysis hydroxyl ions are basic. As pH can be affected by are interpreted by graphs concerning the World chemicals in the water, pH is a vital indicator of Health Organization (WHO) standard. In addition, water that is changing chemically. the bi-plot of Physico-chemical parameters, and the Figure 4 shows the pH of the groundwater in the spatial variations of water quality maps were generated study area. A total of 18 borehole samples were mea- using Excel and Inverse Distance Weighted (IDW) sured; out of them, 12 boreholes’ pH values were not interpolation technique using Arc GIS software, in the range recommended by WHO (6.5–8). Only 6 respectively. wells were within the pH range recommended by The DRASTIC method The method assesses vertical vulnerability based on 7 Table 2. DRASTIC vulnerability classification (Traore et al., different physical parameters that are involved in the 2016). transport and attenuation of contaminants. The Degree of vulnerability Vulnerability index Very low 0–84 DRASTIC vulnerability index (ID) is calculated as Low 85–114 the sum of the products of the scores and the weights Medium 115–145 of the corresponding scores (Panagopoulos et al., High 146–175 Very high 176–226 2006): 6 A. M. DIALLO ET AL. PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10PF11PF12PF13PF14PF15PF16PF17PF18 wells Variation of groundwater pH in the study area Figure 4. Variation of groundwater pH in the study area. Figure 5. The spatial variation of pH in the study area. WHO and exhibited the spatial variation of pH in the et al. (2014), Massally et al. (2017), and Dwirama Putra study area, as can be seen in Figure 5. et al. (2018), and Mali et al. (2020).The acidity of the Generally, groundwater in the study area is acidic. Low Dabiss groundwater was probably due to the acid-base pH groundwater favors the dissolution of metals into the reactions that resulted in the chemical composition of the groundwater system with remarkably high levels. The rocks that host the water. As a result of the action of groundwater, consequently, turns out to be unsafe for meteoric waters originally rich in carbonic acid HCO3, human drinking (Kortatsi, 2006; Shafiq et al., 2021). through the excavation, oxidation, and retention zones of Similar results of low pH values were also found by the lateritic clay cover, the capillary fringe receives acid several authors such as Ayantobo et al. (2013), Akil rainwater directly. This increased the H+ ion content and pH GEOLOGY, ECOLOGY, AND LANDSCAPES 7 weakens the pH, which becomes increasingly acidic. & Ayenew, 2016). From Figure 8, the current study Acidity in water is not in itself harmful to health. The showed that the EC value was between 15 µS/cm and concern for acidity in drinking water is that even mildly 567 µs/cm. acidic water can dissolve metals and other substances. From the spatial distribution of EC in Figure 9, it Consequently, acidic waters can negatively impact health can be viewed in general that EC values are low (low through the long-term development of respiratory alka- mineralization) in the study area. Comparing the EC losis, metabolic alkalosis, acido-respiratory and diabetic values obtained with the values in Table 3, it may say ketoacidosis pathologies (CIRA, 2018).Figure 6 shows the that, 7 wells (PF2; PF6; PF9; PF13; PF14; PF15, and relationship between Physico-chemical parameters in the PF16) were below 100 µS/cm, which indicates very low study area. There is an observable pattern of relationship mineralization; 8 other wells (PF1; PF4; PF5; PF8; between pH and Electrical Conductivity (EC; Figure 6b). PF10; PF12; PF17 and PF18) were in the range of The moderate positive correlation (r = 0.62) between pH 100–200 µS/cm, which shows low mineralization; and EC indicated that the EC decreases when the pH and 2 wells (PF7 and PF11) were ionized (in the decreases, but moderately. This interpretation should be range of 400–600 µS/cm) and were the level of ionic taken with caution because these two concepts are not concentration activity due to moderate dissolved related, and it is open to debate. Again, from Figure 6, the solids. This moderate mineralization in PF11 and pattern of the relationship between pH and other para- PF7 can be additionally observed in Figure 9. meters is not clear. From Table 1, the depths of the well (PF11 and PF7) were relatively deep; hence there will not be much contamination due to percolation. The average- Temperature (moderate) mineralization value in PF11 and PF7 Figure 7 shows the temperature of the groundwater in was possibly due to the presence of mineral salts in the study area, and it was relatively high during the the rocks crossed where they are dissolved by the sampling session, a period corresponding to the end of water during the transition, before reaching the the rainy season in the Republic of Guinea. These aquifer. temperatures were not showing great variations from one point to another, and this indicator is a function of the amount of dissolved oxygen. The minimum value Dissolved Oxygen (DO) was 26.5°C and the maximum value was 33.9°C for all Dissolved Oxygen (DO) level has a vital effect on samples. In general, the temperature in this study area groundwater quality by regulating the valence state was found within the permissible limit of WHO of trace metals and by constraining the bacterial meta- (30°C). A similar observation about temperature var- bolism of dissolved organic species (Rose & Long, iations was also as reported by Massally et al. (2017); 1988). DO levels provide important information and Dwirama Putra et al. (2018). Increased tempera- about the stability of many organic and inorganic ture values released a change in density, reduction in contaminants in groundwater. For these reasons, DO viscosity, and a decrease in the solubility of gases. It concentrations should be determined as part of most should be noted that water temperature has no direct groundwater quality monitoring surveys (Rose & impact on human health. Long, 1988). From Figure 6e, there is a visible pattern of relation- According to the WHO, DO levels should be main- ship between EC and temperature. EC was relatively tained as close to saturation as possible. There is no dependent on temperature (r = 0.42). As mentioned guidance value on health criteria (Prasad et al., 2014). by Mali et al. (2020), EC is affected by geology and In the absence of a Guinean and WHO standard, temperature, the warmer the water the higher the the Moroccan and French potability standards (70 and conductivity (Mali et al., 2020). Temperature affects 75% respectively) were used to qualify the water qual- the EC of water, because of the effect it has on the ity. Figure 10 shows the DO of the groundwater in the viscosity of water and the nature of ions (Saito et al., study area. The percentage of DO saturation in the 2016). Again, from Figure 6, the temperature did not wells of the study area is within the potability stan- show a clear relationship with other parameters. dards. From Figure 10, it was found that all DO values were low and their vary between 1.5 and 6.1%. DO Electrical conductivity (EC) shows a pattern of a relationship with temperature EC measures the ability of water to transmit an electric which is weak(r = 0.35; Figure 6h). It can be deduced current. Pure water is a poor electrical conductor. that temperature does not have a direct influence However, the ability of water to transmit electricity on DO. increases as the amount of dissolved solutes increases. Figure 8 shows the EC of the groundwater in the study Turbidity area. Table 3 shows the relationship between EC and Turbidity measurement is used to clarify visual informa- water mineralization. Referring to WHO standards, tion about the water. Turbidity reflects the presence of the EC value should not exceed 400 μS/cm (Meride suspended particles in the water for example, organic 8 A. M. DIALLO ET AL. (a) (b) (c) 7 8 7 1 1 0 5 10 0 500 1000 0 500 1000 PH EC (μs/cm) EC (μs/cm) (d) (e) (f) 140 40 20 5 5 0 500 1000 0 100 200 0 200 400 600 EC (μs/cm) Turbidity (NTU) EC (μs/cm) (g) (h) (i) 140 40 140 120 120 100 100 80 80 60 60 20 20 0 5 10 0 5 10 0 5 10 DO (mg/L) PH DO (mg/L) (j) 0 5 10 PH Figure 6. Relationship between physico-chemical parameters. (a) DO vs pH; (b); (b) pH vs EC; (c) DO vs EC; (d) Turbidity vs EC; (e) Temperature vs EC; (f) Temperature vs Turbidity; (g) Turbidity vs DO; (h) Temperature vs DO; (i)Turbidity vs pH; (j) Temperature vs pH. Turbidity (NTU) Turbidity(NTU) DO Temperature (C°) PH Temperature (C°) Temperature (C°) Temperature (C°) DO Turbidity (NTU) GEOLOGY, ECOLOGY, AND LANDSCAPES 9 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Wells Figure 7. Variation of groundwater temperature in the study area. PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Wells Electrical conductivity of the groundwater in the study area. Figure 8. Electrical conductivity of the groundwater in the study area. suspended particles in the water (turbid water). The sig- Table 3. Relationship between electrical conductivity and nificant presence of suspended particles is probably water mineralisation (Courtois & Béchennec, 1999). related to the geological nature of the subsoil, which is Conductivity in µs/cm, at 20°C Water mineralisation partly made up of bauxite mineralization. From <100 Very low mineralization Figure 6g, turbidity shows a pattern of a relationship 100–200 Low mineralization 200–400 Increased mineralisation with DO which is weak(r = 0.39; Figure 6h). It can be 400–600 Average mineralization said that turbidity does not have a direct influence on DO. 600–1000 High mineralization 1000 > Excessive mineralisation The results regarding the presence of anions and cations in the groundwater of the investigation area are summarized in Table 5. debris, clays, and microscopic organisms. Table 4 shows Major ions the common turbidity classification. According to the Anions WHO standard for turbidity of drinking water is 5 3- NTU. Figure 11 shows the turbidity of the study area. It Phosphates (PO ) was found that the turbidity values in 11 boreholes cor- In groundwater, various oxidized forms of phos- respond to the WHO values. Six (6) boreholes were phorus can be attached to ortho-phosphate, and the slightly turbid water and borehole PF6 contained a very analytical method did not allow them to be separated. high turbidity value. This means the presence of The ortho-phosphatic acid H PO can ionize in 3 4 Conductivity (μS/cm) Temperature (°C) 10 A. M. DIALLO ET AL. Figure 9. The spatial variation of electrical conductivity based on .Table 3 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Drilling wells Figure 10. Dissolved oxygen of the groundwater in the study area. Table 4. Common turbidity classification (NTU nephelometry levels in groundwater are often linked with turbidity unit). a natural decomposition of rocks and minerals, NTU < 5 Clear water and anthropogenic sources include; fertilizers, was- 5 < NTU < 30 Slightly cloudy water tewater and septic system effluent, and animal NTU > 50 Cloudy water waste (Fadiran et al., 2008). Deep groundwater suggests that natural geologic sources might have − −2 3- a greater influence on concentrations in ground- different ways. H PO ↔H PO ↔HPO ↔PO 3 4 2 4 4 4 water than anthropogenic sources (Welch et al., (Courtois, 2000). 3- 2010). Besides, the study area population is agro- PO concentrations, as shown in Table 5, vary 3- pastoral. The presence of significant amounts of from 0 to 1.34 mg/l. It was found that PO values 3- PO4 in PF3 may indicate the recent contamina- were lower than the WHO standard of 0.5 mg/l. tion resulting from natural and/ or anthropogenic Except for well PF3 (1.34 mg/l), which exceeds the 3- 3- sources. Naturally occurring levels of PO4 in WHO standard. PO are not very mobile in soils groundwater body is not dangerous to human and they are only moderately soluble. Its enhanced dissolved O (mg/l) 2 GEOLOGY, ECOLOGY, AND LANDSCAPES 11 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Drilling wells Figure 11. Turbidity of groundwater in the study area. Table 5. Major anion and cation ions present in the groundwater of the study area. 3 + 2 3+ 3+ 2+ Identifier PO₄ ⁻ (mg/L) NH₄ (mg/L) SO₄ ⁻ (mg/L) F⁻ (mg/L NO₃⁻ (mg/L) Al (mg/L) Cr (mg/L) Zn (mg/L) PF1 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF2 0,315 <1,0 <40 <0,1 <5 >0,5 0,048 <0,02 PF3 1,340 10,200 203 <0,1 <5 <0,02 <0,03 <0,02 PF4 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 0,046 PF5 <0,2 <1,0 <40 <0,1 <5 0,047 <0,03 <0,02 PF6 <0,2 <1,0 <40 <0,1 <5 0,049 <0,03 <0,02 PF7 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF8 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF9 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF10 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF11 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF12 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 0,087 PF13 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF14 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF15 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF16 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF17 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF18 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 0,285 OMS 0,5 2 250 1,5 50 0,2 0,03 3 mg/l 3- health. On the contrary, very high levels of PO4 250 mg/l, than the WHO standard for the quality of can cause digestive problems (Fadiran et al., 2008). water intended for consumption. Nitrate (NO ) Fluoride (F ) Nitrate is an important parameter in water and it is One of the most important elements in drinking water a naturally occurring inorganic ion present in our related to health is fluoride. This is in the form of environment. NO comes from the complete oxida- fluoride ions (F ). Fluoride in water comes mainly tion of organic nitrogen under the action of nitrifying from the dissolution of natural minerals in rocks and bacteria and nitrates from the incomplete oxidation soils with which the water reacts. Fluoride concentra- under the action of Nitrosomonas (Hamsatou, 2005). tions below 0.5 mg/l in drinking water can promote NO in groundwater is a primary indicator of anthro- tooth decay. At very high concentrations exceeding pogenic pollution. In the study area, low values of 1.5–2 mg/l, fluoride in drinking water can cause dental NO than that of the WHO standard of 50 mg/l or bone fluorosis and other skeletal (Matini et al., (Table 5) and indicated the absence of nitrogenous 2009). fertilization in the land surrounding the points stu- According to the result of the analysis of our sam- died. Consequently, these waters were not polluted ples in Table 5, the fluoride levels vary from 0 to with NO . 0.1 mg/l and are below than the WHO standard (1.5 mg/l). This showed that the waters were not 2- −. Sulphates (SO ) polluted with F Similar results were found by Sulfate is a major anion in most groundwater. Ayantobo et al. (2013); Massally et al. (2017) and According to the results of the samples analyzed as they stated that groundwater might be due to its acidic can be seen in Table 5, the values were not exceeded nature which renders it immobile. The F in the Turbidity (NTU) 12 A. M. DIALLO ET AL. analyzed waters could come from the dissolution of PF2 could be explained by the acidity of the water silicates. Since the F-ion has the same ionic radius as (acid water can increase the solubility of heavy the OH-ion, it could therefore be substituted for it in metals). Note that; Figure 4 showed that the pH of these minerals (Matini et al., 2009). the water in the well PF2 was 4.2 lower than 5. In other words, the Al-rich ground through which the well was drilled could be the cause of this high concentration. Cation Ammoniacal nitrogen (NH ) 3+ Chromium (Cr ) Ammoniacal nitrogen is present in toxic form (NH ). 4 3+ Cr which is one of the so-called toxic substances can Its presence in water usually reflects a process of be found in the water table due to human activities incomplete degradation of the organic matter. NH , such as the textile industry. Tanneries and explosives is transformed rather quickly into nitrite by oxidation 3+ are also anthropogenic sources of Cr , as well as (Hamsatou, 2005). In the study area, NH levels vary domestic waste buried in the subsoil without (Table 5) from 0 to 10.2 mg/l. Comparing these values 3+ a protective perimeter. Cr has two oxidation states to the WHO permissible value of 2 mg/l, borehole PF3 (+III and +IV) of which the more soluble, mobile form shows a value (10.2 mg/l) higher than the norm. Note and therefore the most toxic is hexavalent chromium 3- that, Well PF3 showed higher PO concentration. (Matini et al., 2009). 3- High PO concentrations in groundwater are gener- As can be seen in Table 5, the analysis shows low ally linked with high ammonia, near neutral pH, and 3+ levels of Cr and below than the WHO standard of anoxic conditions (Griffioen, 2006). Agricultural 3+ 0.03 mg/l. The Cr values of the sampled boreholes activity is a potential source of NH4. The population were between 0 and 0.048 mg/l. In this sense, it may in Dabiss is essentially agro-pastoral. The presence of conclude here that the groundwater in the study area the high NH + value in the well PF3 may be due to 4 3+ was away from Cr pollution. farmer activity. Interpretation of DRASTIC parameters and 2+ Zinc (Zn ) production of vulnerability maps 2+ Zn , like copper, is a trace metal element in magmatic The DRASTIC map presents a view of the relative rocks. It can be found in oxygenated waters rich in degree of vulnerability of a study area. The potential 2+ iron and manganese. Zn , can be of anthropogenic for pollution increases with the index (Latifi & Chaab, origin, through leaching from urbanized and indus- 2017). The partial index maps were obtained from trialized areas (Courtois, 2000). geological, topographical, hydrogeological, pedologi- 2+ The Zn , content of all the water varied from 0 to cal, hydrodynamic, and hydroclimatic data (Latifi & 0.28 mg/l (Table 5). All the values found in this ana- Chaab, 2017). This allowed the definition of the seven lysis were within the WHO standard (3 mg/l). This can (7) DRASTIC parameters. The distribution of index be explained by the geological nature of the terrain values for each parameter (weight×highest) is repre- through which the water flows. The presence of this sented on a map. Sectors with a high risk of pollution metallic element in the study area groundwater is not have strong coastlines and those with less risk have dangerous for consumption. a low value. The synthesis map of the vulnerability to pollution of the aquifer was obtained by making the 3+ weighted sum of the partial index values of the seven Aluminium (Al ) (7) DRASTIC parameters. There are several possible reasons for the contamina- 3+ tion of groundwater by Al : the soil through which 3+ 3+ the water flows are rich in Al and Al of industrial Depth to water table parameter “D” 3+ origin (Kholtei et al., 2003). On the other hand, Al is a trace element that only exists in solution in the The depth to water table defines the thickness of the 3+ exchangeable form Al , when the acid pH is below 5 aeration zone materials through which a contaminant (Courtois, 2000). The 18 water samples in the study percolates before reaching the groundwater. area were analyzed and found that only borehole PF2 Generally, attenuation capacity increases with depth shows a value above than the WHO drinking water (Latifi & Chaab, 2017). standard (0.2 mg/l). This result can be seen in Table 5. In the case of the present study, the depth of the 18 A similar finding was reported by Ayantobo et al. boreholes drilled varies from 50.55 to 89.95 m above (2013); Kusin et al. (2017). Bauxite is an aluminous 31 m, giving us a partial vulnerability index of order 5 rock that contains hydrated aluminium oxide as (Table 6). The index calculated in this way was used to 3+ a major constituent. The high Al value in borehole draw up the corresponding map (Figure 12). GEOLOGY, ECOLOGY, AND LANDSCAPES 13 Figure 12. Map of the depth parameter “D.” Figure 13. Map of net recharge parameter “R.” Parameter of the net recharge “R” The observation of the recharge map (Figure 13) shows that the infiltration was the same over the whole The recharge of the water table comes mainly from the study area. The calculation of the water balance gave direct infiltration of rainwater through the permeable an average value of effective infiltration estimated at layers and runoff water, or floods in the beds of tribu- 89.93 cm, in a range above 25 cm with a partial index taries (Latifi & Chaab, 2017). of 36. This parameter is reported in Table 7. 14 A. M. DIALLO ET AL. Table 8. Aquifer type parameter. Table 6. Parameter of the depth of the water table. Nature of the aquifer “A” Depth of the water table “D” Nature of the aquifer environment Score Partial index Interval (m) Score Partial index Shale 2 6 >31 01 05 Weight: 03 Weight: 05 an index of 18; Silts soils have an index of 8; and Clay an index of 6 (see, Table 9). Table 7. Recharge parameter. Net recharge “R” Interval (cm) Score Partial index Topographical parameter “T” >25 09 36 The slope of the land has a direct influence on the con- Weight: 04 centration time of the pollutants. It controls some para- meters such as infiltration (Latifi & Chaab, 2017). Parameter of the nature of the aquifer “A” Examination of the topographic map of the region reveals three (3) types of slope (Figure 16). The Topographic The determination of this parameter results from the parameters can be seen in Table 10. borehole data (Latifi & Chaab, 2017). The nature map of the aquifer (Figure 14) is characterized by shale, throughout the study area. The index calculated in Parameter impact of the unsaturated zone “I” Table 8 is equal to 6. The impact of the unsaturated zone (aeration zone) is a very important parameter in the application of the DRASTIC method. This parameter was studied based Parameter nature of soil type “S” on the nature of the lithology of the study area (Traore This parameter has an impact on the fringe of water that et al., 2016). The nature and thickness of the part penetrates through the soil to reach the water table. In between the soil surface and the aquifer control to other words, it is the vertical migration of pollutants some extent the vulnerability to groundwater pollu- through the saturated zone (Latifi & Chaab, 2017). The tion (Latifi & Chaab, 2017). The map of the unsatu- soil type map (Figure 15) shows sand, silts, and clay soils. rated zone (Figure 17) shows clay and shale. The Sand soils have corresponding index is mentioned in Table 11. Figure 14. Map of aquifer nature parameter. GEOLOGY, ECOLOGY, AND LANDSCAPES 15 Figure 15. Soil type parameter map. Table 9. Soil type parameter. Hydraulic conductivity parameter “C” Soil type parameter The permeability coefficient map is drawn up by Nature of the soil Score Partial index pumping tests in the different boreholes. The perme- Sand 9 18 Silts 4 8 ability coefficient reflects the speed at which water, Clay 3 6 transports the pollutant by dispersion in the subsoil Weight: 02 (Latifi & Chaab, 2017). The index of this parameter is Figure 16. Topographic parameter map. 16 A. M. DIALLO ET AL. Figure 17. Unsaturated zone parameter map. Table 10. Topographic parameter. indices (Latifi & Chaab, 2017). With the application of Topographic parameter the DRASTIC method, we obtained a vulnerability index equal to ninety-four (94). According to the Intervals (%) Score Partial index classification of the US Environmental Protection 2–6 9 9 6–12 5 5 Agency, as shown in Table 2, the vulnerability index 12–18 3 3 of our study area is in the range of 85–114. Weight: 01 A reading of the vulnerability map (Figure 19) shows that the groundwater in the study area has Table 11. Unsaturated zone parameter. a low vulnerability. This is explained by the reduction Impact of the unsaturated zone “I” in the propagation of the pollutant due to the texture and structure of the rocks in the vadose zone, the Nature of the unsaturated zone Score Partial index Clay 1 5 depth of the aquifer, the slopes, and the permeability Shale 3 15 of the overlying layers. Weight:05 Limitations and future work reported in Table 12. The observation of the hydraulic conductivity map (Figure 18) shows that the conduc- It is important to emphasize that the results of this tivity was the same over the whole area. study are only generalized to the Dabiss South area in and around the mine concession. Despite the study exposing good water quality for most para- The vulnerability map meters, all areas of Dabiss were not investigated which is noted to be one of the limitations of the The vulnerability map of the water table allows visua- investigation. The limitation is also due to a lack of lizing the main risk areas which are related to high hydrogeochemical data over a long period based on advanced analytical chemical methods such as the Table 12. Hydraulic conductivity parameter. Inductively Coupled Plasma-Mass Spectrometer Hydraulic conductivity “C” (ICP-MS). Intervals (m/s) Score Partial index However, the results gained from this research −7 −5 4,72 × 10 -4,01 × 10 1 3 for the first time would be a guideline for future Weight: 03 research in the prefecture of Boke. For a depth GEOLOGY, ECOLOGY, AND LANDSCAPES 17 Figure 18. Hydraulic conductivity parameter map. Figure 19. Vulnerability map of the study area. analysis of water quality in the Dabiss area, the research. Different sampling campaigns should be monitoring and analysis should be done for carried out in all Dabiss areas. Test samples (raw a longer period of time. The minimum time for ore, soils, discharges, surface water, and ground- such monitoring should be one year to obtain water) should be collected for analysis and bauxite a series of data that confirm the reliability of the mining tests in the laboratory. 18 A. M. DIALLO ET AL. Volume13/4-Water-Quality-Evaluation-of-Hand-Dug. Conclusion pdf Bah, I. L. (2013) Etude des fossiles caracteristiques de la In this work, we analyzed groundwater vulnerability to feuille Kandiafara. Mémoire de diplôme de fin d’etude pollution in the sub-prefecture of Dabiss, one of the superieure, Institut Superieur des Mines et Geologie de bauxite mining areas of the Boké Prefecture. In sum- Boke. ISMGB. mary, the following observations were made when Bakouan, C., Guel, B., & Hantson, A.-L. (2017). Caractérisation physico-chimique des eaux des forages analyzing the Physico-chemical parameters of the des villages de Tanlili et Lilgomdé dans la région Nord water samples and the DRASTIC vulnerability map. du Burkina Faso - Corrélation entre les paramètres phy- The majority of the groundwater in the study area sico-chimiques. Afrique SCIENCE, 13(6), 325–337. seems to be acidic. In our case, the acidity of these https://www.afriquescience.net/PDF/13/6/27.pdf waters is probably explained by an in-situ Barbulescu, A. (2020). Assessing Groundwater phenomenon. Vulnerability: DRASTIC and DRASTIC-Like Methods: A Review. Water, 12(5), 1356. https://doi.org/10.3390/ In the study area, most of the groundwater from w12051356 drinking wells analyzed is complying with WHO stan- Batchi, M., Al Kalkouri, J., Fenjiro, I., & El Maaqili, M. dards. It was found that a low vulnerability of ground- (2017). Etude comparative de deux modèles (DRASTIC water in the study area. et SI) pour l'évaluation de la sensibilité de la nappe The outcomes gained from this research may be phréatique de Mnasra (Nord-Ouest Marocain) à la pollu- tion d'origine agricole. Physio-Géo, 11, 43–64. https://doi. improved by incorporating other social, and ecological org/10.4000/physio-geo.5213 factors, as well as the use of mathematical modeling to Campbell, B., & Hatcher, P. (2019). Neoliberal reform, con- improve the model efficiency. testation and relations of power in mining: Observations From the above, the study recommends that the from Guinea and Mongolia. The Extractive Industries and SMB mining company should develop water- Society, 6(3), 642‑653. https://doi.org/10.1016/j.exis.2019. monitoring programs by collecting water samples for 06.010 Chen, X., 1, Li, X., 2, Wu, P., 3, Xuefang, Z., 4, Yabin, L., 5, laboratory analysis or by using probes so that mine Tao, W., 6, & Wenrui, R. (2022). The development and operators can gauge the impact that their mine was utilization of bauxite resources in the Guizhou Province having on the local environment. It will reveal the and relevant challenges to the ecology and the quality and composition of groundwater and surface environment. Gospodarka Surowcami Mineralnymi - water over time, as well as over weeks, months, and Mineral Resources Management, 38(2), 5–30. https://doi. org/10.24425/gsm.2022.141667 years. Besides, SMB should grant agricultural inputs CIRA. (2018). Étude de caractérisation environnementale et free of persistent organic pollutants to a farmer, and sociale des activités minières en cours. Rapport du Projet also train them in agricultural techniques up to the d'Alimentation en Eau Potable et d'Assainissement dans marketing of products from their plains. Finally, SMB les Préfectures de Boké et de Télimélé (PAEPA-BT). and the entire community should be educated on the Courtois, N. (2000). Ressources en eaux soutet~aincs en zone health risk linked with human exposure to water de socle de la Vendée -. Aspects qualitatifs. BRGM. http:// infoterre.brgm.fr/rapports/RP-50394-FR.pdf pollution. Courtois, N., & Béchennec, F. (1999). Groundwater resources in the Vendée basement zone. BRGM. Dresse, A., Nielsen, J. Ø., & Fischhendler, I. (2021). From Disclosure statement corporate social responsibility to environmental peace- building: The case of bauxite mining in Guinea. Resources No potential conflict of interest was reported by the Policy, 74, 102290. https://doi.org/10.1016/j.resourpol. author(s). 2021.102290 Ducommun, R., 2010. Estimation and mapping of ground- References water vulnerability in urban areas (PhD Thesis). University of Neuchâtel. Dwirama Putra, R., Apriadi, T., Suryanti, A., Irawan, H., Affandi, F. N. A., Kusin, F. M., Sulong, N. A., & Madzin, Z. Said Raja, T., & Yulianto, T.(2018) Preliminary study of (2018). Hydrogeochemical assessment of mine-impacted heavy metal (Zn,Pb, Cr, As, Cu, Cd) contaminations on water and sediment of iron ore mining. IOP Conference different soil level from post-mining bauxite production Series: Earth and Environmental Science, 140 (1), 012023. for aquaculture, SCiFiMaS 2018, E3S Web of Conferences IOP Publishing.https://doi.org/10.1088/1755-1315/140/ 47, 02008, https://doi.org/10.1051/e3sconf/20184702008 1/012023 Ewodo Mboudou, G., Auguste, O., Bon, A. F., Ntep, F., & Akil, A., Hassan, T., Fatima, E.H., Lahcen, B., Abderrahim, Bineli, E. (2016) Apport des méthodes paramétriques L., (2014). Etude de la qualité physico-chimique et con- DRASTIC, GOD et SI à l’évaluation de la vulnérabilité tamination métallique des eaux de surface du bassin ver- intrinsèque dans les aquifères du bassin versant de sant de guigou, maroc. European Scientific Journal, ESJ, l’abiergué (région de Yaoundé). Science de la vie, de la 10(23). https://doi.org/10.19044/esj.2014.v10n23p%p terre et agronomie,Revue CAMES, 4, 67–78. ISSN 2424- Ayantobo, O. O., Oluwasanya, G. O., Idowu, O. A., & 7235 file:///C:/Users/p/Downloads/R%C3%A9sum%C3% Eruola, O. A., (2013). Water quality evaluation of hand- A9.%20Abstract.%20EWODO%20MBOUDOU% dug wells in ibadan, oyo state, Nigeria. Global Journal of 20Guillaume%201,%202_,%20OMBOLO%20Auguste% Science Frontier Research Agriculture and Veterinary, 13 201,%20BON%20Andr%C3%A9%20Firmin%202,%203, (10) Version 1.0. https://globaljournals.org/GJSFR_ GEOLOGY, ECOLOGY, AND LANDSCAPES 19 %20NTEP%20Fran%C3%A7ois%202,%20BINELI% Dist-Kolhapur, Maharashtra State, India. International 20Etienne%203.pdf. ,%4_,%20OMBOLO%20Auguste% Research Journal of Environment Sciences, 4, 77–83. 201,%20BON%20Andr%C3%A9%20Firmin%202,%203, Latifi, S., & Chaab, S. (2017). Evaluation and mapping of %20NTEP%20Fran%C3%A7ois vulnerability to groundwater pollution, using DRASTIC Fadiran, A. O., Dlamini, S. C., & MavusoBull, A. (2008). and GOD methods, in the alluvial plain of Guelma, A comparative study of the phosphate levels in some North-East Algeria. Reviesed Science Technolgy Synthese, surface and groundwater bodies of Swaziland Chem. 34, 48–62. https://www.ajol.info Society of Ethiopia, 22(2), 197–206. https://doi.org/10. Lee, K. Y., Ho, L. Y., Tan, K. H., Tham, Y. Y., Ling, S. P., & 4314/bcse.v22i2.61286 Qureshi, A. M. (2017). Environmental and occupational Frost-Killian, S., Master, S., Viljoen, R. P., & Wilson, M. G. health impact of bauxite mining in Malaysia: A Review. (2016). The great mineral fields of Africa introduction. IIUM Medical Journal Malaysia, 16(2). https://doi.org/10. Episodes Journal of International Geoscience, 39(2), 85– 31436/imjm.v16i2.346 103. https://doi.org/10.18814/epiiugs/2016/v39i2/95770 Machiwal, D., Jha, M. K., Singh, V. P., & Mohan, C. (2018). Griffioen, J. (2006). Extent of immobilization of phosphate Assessment and mapping of groundwater vulnerability to during aeration of nutrient-rich, anoxic groundwater. pollution: Current status and challenges. Earth-Science Journal of Hydrology, 320(3–4), 359–369. https://doi. Reviews, 185, 901–927. https://doi.org/10.1016/j.ear org/10.1016/j.jhydrol.2005.07.047 scirev.2018.08.009 Hamsatou, M. M. D., 2005. University of Bamako, p. 135. Mali, S. C., Thabaj, K. A., & Purandara, B. K. (2020). He, H., Li, X., Li, X., Cui, J., Zhang, W., & Xu, W. (2018). Evaluation of geochemical characteristics of groundwater Optimizing the DRASTIC method for nitrate pollution in in parts of ghataprabha sub-basin using DRASTIC groundwater vulnerability assessments: a case study in indices. Journal of the Geological Society of India, 95(5), China. Polish Journal of Environmental Studies, 27(1), 513–519. https://doi.org/10.1007/s12594-020-1470-8 95–107. https://doi.org/10.15244/pjoes/75181 Mamedov, V. I., Bouféév, Y. V., Nikitine, Y. A., & Human Rights Watch., 2018 « Quels bénéfices en tirons-nous Mamedov, A. I. (2010). database of useful mineral deposits ? » Impact de l’exploitation de la bauxite sur les droits and indices/Ministry of Mines and Geology Rep. of Guinea. humains en Guinée. https://www.hrw.org/sites/default/ GEOPROSPECTS Ldt; Univ. e of Moscow State files/report_pdf/guinea1018fr_web.pdf Lomonosov (Fac. Geol)-Conakry-Moscow. Institut National de la Statistique (INS)., 2016. Annuaire Massally, R.-E. M., Sheriff, A. B., Kaitibi, D., Abu, A., statistique, République de Guinée, p. 50. Barrie, M., & Taylor, E. T. (2017). Comprehensive assess- Keita, M., & Traore, O. (2020). Environmental impact of ment of groundwater quality around a major mining Open PIT Mining: Case of Bauxite Mining in Guinea - company in Southern Sierra Leone. Journal of Water A Review -. International Journal of Applied Resource and Pro- Tection, 9(6), 601–613. https://doi. Environmental Sciences, 15 (2), 167–177. https://www. org/10.4236/jwarp.2017.96040 ripublication.com/ijaes20/ijaesv15n2_01.pdf 09736077 Matini, L., Moutou, J. M., & Kongo-Mantono, M. S. (2009). 09736077 Hydro-chemical evaluation of groundwater in an urban Kholtei, S., Bouzidi, A., Bonini, M., Fekhaoui, M., Sbai, K., environment in the southwest of Brazzaville, Congo. Anane, R., & Creppy, E. E. (2003). Contaminations des African Journal of Science and Technology, 5. https://doi. eaux souterraines de la plaine de Berrechid dans la région org/10.4314/afsci.v5i1.61709 de Chaouia, au Maroc, par des métaux présents dans les Meride, Y., & Ayenew, B. (2016). Drinking water quality eaux usées : Effet de la pluviométrie. Eaux Souterraines. assessment and its effects on residents health in Wondo Vecteur Environ, 36, 68. https://www.researchgate.net/ genet campus, Ethiopia. Environmental Systems Research, profile/Fekhaoui-Mohamed/publication/259674788_arti 5(1). https://doi.org/10.1186/s40068-016-0053-6 cle_kholti_et_al/links/0046352d48c8d82403000000/arti Moe, C. L., & Rheingans, R. D. (2006). Global challenges in cle-kholti-et-al.pdf water, sanitation and health. Journal of Water and Health, Kitula, A. G. N. (2006). The environmental and 4(S1), 41–57. https://doi.org/10.2166/wh.2006.0043 socio-economic impacts of mining on local livelihoods Neha Gupta. (2014). Groundwater Vulnerability in Tanzania: A case study of Geita District. Journal of Assessment using DRASTIC Method in Jabalpur Cleaner Production, 14(3‑4), 405‑414. https://doi.org/10. District of Madhya Pradesh. International Journal of 1016/j.jclepro.2004.01.012 Recent Technology and Engineering (IJRTE), 3(3). 2277– Knierzinger, J. (2014). The socio-political implications of 3878. https://www.ijrte.org/wp-content/uploads/papers/ bauxite mining in Guinea: A commodity chain v3i3/C1133073314.pdf \ perspective. The Extractive Industries and Society, 1(1), Nurroh, S., Totok gunawan, and Andri Kurniawan 20–27. https://doi.org/10.1016/j.exis.2014.01.005 Assessment of groundwater pollution risk potential Kortatsi, B. K. (2006). Concentration of trace metals in using DRASTIC Model in Yogyakarta City, Indonesia, boreholes in the Bassin d’Ankobra, Ghana. West African E3S Web of Conferences 200, 02002 (2020) DOI: https:// Journal of Applied Ecologyis, 10, 73–87. https://doi.org/10. doi.org/10.1051/e3sconf/202020002002 4314/wajae.v10i1.45706 Panagopoulos, G. P., Antonakos, A. K., & Lambrakis, N. J. Kusin, F. M., Rahman, M. S. A., Madzin, Z., Jusop, S., (2006). Optimization of the DRASTIC method for Mohamat-Yusuff, F., Ariffin, M., & Z, M. S. M. (2017). groundwater vulnerability assessment via the use of sim- The occurrence and potential ecological risk assessment ple statistical methods and GIS. Hydrogeology Journal, 14 of bauxite mine-impacted water and sediments in (6), 894–911. https://doi.org/10.1007/s10040-005-0008-x Kuantan, Pahang, Malaysia. Environmental Science and Prasad, B. S. R. V., Srinivasu, P. D. N., Varma, P. S., Pollution Research, 24(2), 1306–1321. https://doi.org/10. Raman, A. V., & Ray, S. (2014). Dynamics of dissolved 1007/s11356-016-7814-7 oxygen in relation to saturation and health of an aquatic Lad, R. J., & Samant, J. S. (2012). Impact of bauxite mining body: A case for Chilka Lagoon, India. Journal of Ecosystems, on soil: A case study of bauxite mines at Udgiri, 2014, 1–17. https://doi.org/10.1155/2014/526245 20 A. M. DIALLO ET AL. Rao, M. J., Prasad, C. H., Mohammad, M., Kakkassery, A. I., Journal of Agricultural and Biological Engineering, 11(2), et al. (2016). Bauxite mining in Eastern Ghats of Andhra 115–121. https://doi.org/10.25165/j.ijabe.20181102.2747 Pradesh, possible environmental implications and mea- Singh, V. S., Prasad, R. K., & Banerjee, P. (2010). sures for environmentally friendly mining. International Vulnerability of groundwater in an industrial (Bauxite) Journal of Science and Research, 5, 1434–1437. valley of Lanjigarh (Orissa), India. Environmental Earth Rodier, J., Legube, B., Merlet, N., & Brunet, R. (2009). Sciences, 60(8), 1739–1751. https://doi.org/10.1007/ L'analyse de l'eau - 9ème édition - Eaux naturelles, eaux s12665-009-0311-2 résiduaires, eau de mer: Eaux naturelles, eaux résiduaires, Souare, S. (2019). Bauxite mining in the Boké Region eau de mer (Technique et ingénierie). DUNOD Edition. (Western Guinea): method used and impacts on physical Rose, S., & Long, A. (1988). Monitoring dissolved oxygen in environment. European Journal of Sustainable ground water: some basic considerations. Groundwater Development Research, 3 (3), em0087. https://doi.org/10. Monitoring & Remediation, 8(1), 93–97. https://doi.org/ 29333/ejosdr/5735 10.1111/j.1745-6592.1988.tb00981.x Soumah, I. (2009). The future of mining industry in Guinea Saito, T., Hamamoto, S., Ueki, T., Ohkubo, S., Moldrup, P., (HARMATTAN), (January 1, 2009). Kawamoto, K., & Komatsu, T. (2016). Temperature Taazzouzte, M., Ghafiri, A., Lemacha, H., El Moutaki, S., & change affected groundwater quality in a confined marine Haidara, I. (2021). Mapping intrinsic vulnerability to aquifer during long-term heating and cooling. Water pollution using the DRASTIC method in the Temara Research, 94, 120–127. https://doi.org/10.1016/j.watres. Groundwater. Systems (IJAEIS), 12(4), 1–18. http://doi. 2016.01.043 org/10.4018/IJAEIS.293753 Samozvantsev, V., & Diallo, H. (1976). Etude géologique des Togba, M. (1977). Projet de prospection préalable des pla- feuilles Kandiafara et Koumbia à l’échelle 1/200000. teaux bauxitiques d’Aye-Koye (Boké). Mémoire de diplôme Société d’exploration géologique Féderation de Russie- de fin d’études supérieures. Institut Supérieur des Mines et Organisme de la recherche géologique. Géologie de Boké, ISMGB. Satouh, A., Boualem, B., Chellat, S., & Benaabidate, L. Traore, P. N., Djedi, H. M., & Khemmoudj, K. (Framer.), (2021). Determination of Groundwater Vulnerability 2016. Comparative study of groundwater vulnerability to Using the DRASTIC Method in Ouargla Shallow pollution in the commune of Souk El Tenine by DRASTIC Aquifer (Algerian Sahara). Journal of Ecological and GOD methods. Université A. MIRA. http://172.17.1. Engineering, 22(6), 12–19. https://doi.org/10.12911/ 105:8080/xmlui/handle/123456789/1022 (Accessed: 20 22998993/137680 January 2021) Shafiq, W., Ullah, H., Zaheer, M., Mehmood, M., Farooq, U., Welch, H. L., U, J. A. K., & Coupe, R. H. 2010 Occurrence of Khan, M. J., Ullah, S., & Ullah, S. (2021). Aquifer character- phosphorus in groundwater and surface water of north- ization and physiochemical analysis of District Dera Ghazi western Mississippi, Mississippi water resources conference Khan Punjab, Pakistan. Rudarsko-geološko-naftni zbornik, Xin, X., Wenxi, L., Leilei, Y., & Haibo, C., “Application 36(3), 47–57. https://doi.org/10.17794/rgn.2021.3.4 of DRASTIC method in groundwater vulnerability Shahab, A., Qi, S., Zaheer, M., Rashid, A., Talib, M. A., & assessment of Jilin City,” 2011 International Ashraf, U. (2018). Hydrochemical characteristic and water Symposium on Water Resource and Environmental quality assessment for drinking and agricultural purposes in Protection, 2011, pp. 286–289, https://doi.org/10.1109/ District Jacobabad, Lower Indus Plain, Pakistan. International ISWREP.2011.5893001. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Geology Ecology and Landscapes Taylor & Francis

Vulnerability of groundwater to pollution at the Dabiss bauxite mining area, Boké Prefecture, Republic of Guinea

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GEOLOGY, ECOLOGY, AND LANDSCAPES INWASCON https://doi.org/10.1080/24749508.2022.2138012 RESEARCH ARTICLE Vulnerability of groundwater to pollution at the Dabiss bauxite mining area, Boké Prefecture, Republic of Guinea a,b a,b a,b c,d Alpha Mamoudou Diallo , Ahmed Amara Konaté , Fassidy Oularé and Muhammad Zaheer Laboratoire de Recherche Appliquée en Géoscience et Environnement, Institut Supérieur des Mines et Géologie de Boké, Boké, Republic of Guinea; Centre Emergent Africain Mines et Société, Institut Supérieur des Mines et Géologie de Boké, Boké, Republic of Guinea; c d Department of Earth & Environmental Sciences, Hazara University, Mansehra, Pakistan; Department of Civil Engineering and Mechanics, Lanzhou University, Chengguan District, Lanzhou, Gansu, China ABSTRACT ARTICLE HISTORY Received 23 February 2022 Boké Prefecture has become a popular mining location, with various extractive corporations Accepted 13 October 2022 competing for bauxite extraction. Water samples were obtained from eighteen water wells across the Dabiss study area. All Physico-chemical parameters and major ions of groundwater KEYWORDS were compared with World Health Organization (WHO) standard. Furthermore, using Excel and Groundwater vulnerability; the Inverse Distance Weighted (IDW) interpolation technique in Arc GIS software, bi-plots of groundwater pollution; Physico-chemical parameters and spatial variations of water quality maps were generated Dabiss bauxite mining; respectively. A vulnerability study of groundwater pollution by mining activities was conducted Prefecture of Boké; Republic of Guinea by applying the standard DRASTIC method. It was found that the drinking water samples of the study areas were usually within the water quality standards of WHO. According to physico- chemical analysis, most of the groundwater in the study area appears to be acidic. An equilibrium was set up in the aquifer between the chemical composition of the water and that of the rocks. The DRASTIC method enabled us to show a low vulnerability index to groundwater pollution. The results of this study could prevent diseases linked to the consump- tion of water contaminated and improve the quality of life of the population and will serve as a reference document in other mining areas. Introduction drinking water quality and their resources (Shahab Water is associated with approximately every type of et al., 2018). In recent years, the negative impact of mining company, whether as groundwater, surface bauxite mining on the environment has been stated by water, or wastewater, and consequently, there is an several authors such as (Chen et al., 2022; Keita & important need to evaluate water quality and quantity Traore, 2020; Lad & Samant, 2012; Rao et al., 2016; conditions in all phases of mining: exploration, pro- Souare, 2019). duction, and decommissioning. Changes in water Preserving the quality of groundwater is most quality can lead to many types of impacts and the important because it may lead to a danger for con- mining company unfortunately creates various such sumption (Ewodo Mboudou et al., 2016), and people problems. One of the standard impacts comes from who use using this contaminated groundwater as groundwater for domestic use. Contaminated water drinking water is at risk of illness in the future may affect human health, animals, and plants. Metal (Bakouan et al., 2017). Consequently, water, which is mining can be linked with some environmental degra- considered a source of life, may become a source of dation even though being a vital source for mineral disease within a large population, due to the mining exploration. This can be associated with the impact on activities which are in full expansion, with the indus- water due to water acidification and the impact of trial revolution. Based on the various challenges of heavy metals (Affandi et al., 2018). Bauxite mining pollution, conformation with drinking water quality activities are a main open cast mining interest that standards is a major concern. reflects substantial adverse effects on the environment Lack of groundwater vulnerability studies in such as dust pollution and negative effects on water mining areas, as well as inadequate infrastructure, resources (Kusin et al., 2017). In bauxite mining areas contributes to the development of waterborne diseases the major sources of water pollution are Al and Fe. (malaria, yellow fever, typhoid fever, cholera, filariasis, Further that when the natural ecosystem is disturbed meningitis, hepatitis A and B, and diarrhea), which are and excavated then other pollutants such as As, Ni, currently responsible for the deaths of more than Hg, Cd, Pb, and other heavy metals may also affect 2.2 million people worldwide each year (Moe & CONTACT Ahmed Amara Konaté konate77@yahoo.fr Laboratoire de Recherche Appliquée en Géoscience et Environnement, Institut Supérieur des Mines et Géologie de Boké, BP 84, Baralandé, Boké, Republic of Guinea © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the International Water, Air & Soil Conservation Society(INWASCON). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 2 A. M. DIALLO ET AL. Rheingans, 2006). Compared to the natural environ- Guinea bauxite reserves are likely at over 40 billion ment, the mining area has specific hydrology which tons and out of them, 23 billion tons are situated in the must be considered when estimating the vulnerability Boké region (Keita & Traore, 2020). Bauxite mining of groundwater; and also, when evaluating the risks of and alumina production offer about 80% of Guinea’s contamination that the exploitation of bauxite has on foreign exchange (Keita & Traore, 2020). Guinea aquifer resources (Ducommun, 2010). The notion of bauxite now makes up a huge amount of the Al used vulnerability of groundwater to pollution is a prime across the world in aero plane, car parts, and consu- concern with hydrogeological parameters which mer products like tin foil and beverage cans. With include lithology, depth to groundwater level, geo- numerous more international companies preparing chemistry, soil, and geomorphology of the investigated to begin exports from Guinea which has the world’s area (Mali et al., 2020). leading bauxite deposits, may soon turn out to be the The DRASTIC method of vulnerability assessment, leading global producer (Knierzinger, 2014). of the parametric type, was developed in the 1980s by The Prefecture of Boké became a mining site where the US Environmental Protection Agency (Batchi several mining companies are competing for bauxite et al., 2017). Because of its practical and intuitive (Dresse et al., 2021). Open-pit mining often consists of approach, the DRASTIC method has been used to the removal of natively vegetated areas and is so one of estimate the vulnerability of groundwater resources. the most environmentally destructive types of mining, For example, (Ducommun, 2010; Singh et al., 2010; especially within tropical forests. All the sub- Xin et al., 2011; Neha Gupta, 2014; Shahab et al., 2018; prefectures of Boké with a bauxite plateau are affected, Machiwal et al., 2018; He et al., 2018; Barbulescu, particularly Dabiss (Knierzinger, 2014). 2020; Mali et al., 2020; Nurroh, 2020; Satouh et al., Dabiss is a sub-prefecture in the Boké Prefecture in 2021; Taazzouzte et al., 2021). The DRASTIC method the Boké Region of western Guinea and it had is still an extremely simple and quick method to use a population of31947people (Institut National de la and perfectly fulfills its role as a preliminary approach Statistique (INS), 2016). Figure 1 shows the presenta- for estimating the vulnerability of an aquifer. This tion of Dabiss. Dabiss has a total area of bare plateau of makes it a practical tool, as it requires little hydrogeo- 5580.860 ha or 55,808,600 m (Knierzinger, 2014) and logical data, but by no means sufficient for the protec- mining activities began in 2015 by the Boké Mining tion of groundwater resources (Barbulescu, 2020). Company (SMB). SMB is a group project that includes Groundwater pollution is now and will increasingly a Chinese company that is the largest aluminum pro- be a major concern for various water specialists in ducer in the world. The SMB group has experienced developing countries. tremendous growth since its creation in 2015; it is now The global bauxite resource has been estimated at the country’s main exporter (Human Rights Watch, more than 70 billion tons, with the largest concentra- 2018). There is an intense need to study the quality of tion in Guinea, where an estimated 25 billion tons of water in and around mining areas to help prevent bauxite might be present (Lee et al., 2017). Guinea is disease and improve the quality of life (Bakouan endowed with extraordinarily rich but underexploited et al.,). subsoil. However, over the past decade, foreign invest- In our study area, mining is carried out in ments in the mining sector increased thanks to open pits, where the vegetation cover is comple- the second wave of liberalization of mining codes tely stripped before reaching the ore. This process (Campbell & Hatcher, 2019). This increased Guinean leads to a vulnerability of the groundwater aqui- production, especially of bauxite. The country thus fers, which helps the pollution of water resources. becomes the second largest producer of this mineral It should be noted that several studies have been in the world, just behind Australia (Frost-Killian et al., conducted on the environmental impact (Dresse 2016). et al., 2021; Keita & Traore, 2020; Souare, 2019) The contribution of the mining sector to Guinea’s and very few on the search for groundwater for GDP rose from 4.2% in 2010 to 7% in 2020 (Frost- drinking water supply (Knierzinger, 2014). Killian et al., 2016). Indeed, the Guinean economy was Despite this work on groundwater in the study supported since independence by the mining sector, area, to our knowledge, no groundwater vulner- which in 2018 represented more than 98% of export ability study in the Dabiss area was conducted. revenues (Soumah, 2009). Mining development The overall aim is to study the impact of bauxite should not only see the short-term economic benefits mining on groundwater in the Dabiss area. but go beyond, by considering all the social and envir- Firstly, to analyze the Physico-chemical para- onmental issues, which were medium to long term. It meters and major elements of groundwater; sec- is widely shown that mines affect the agricultural and ondly, to establish a groundwater vulnerability livestock space of local populations, water resources, map to obtain a solution for protecting aquifers soil fertility, air quality, etc (Kitula, 2006). in the study area. GEOLOGY, ECOLOGY, AND LANDSCAPES 3 Figure 1. The presentation of sub-prefecture of dabiss. This research could prevent diseases linked to the c) Devonian Suite Faro (Dfr): Devonian deposits consumption of water contaminated by bauxite outcrop in the east and northeast of the study area. mining and improve the quality of life of the popula- They are represented by aleurolites, argillites, and tion and will serve as a reference document in other sandstones; brachiopod fossils are found. The end of mining areas. this period was affected by Mesozoic dolerite intrusions. d) The Cenozoic formations: they are essentially Geology, geomorphology, and hydrogeology of represented by undifferentiated deposits (clayey the site sands and alluvial sandy silts with gravels, pebbles, and gravels, clayey sands with angular arena and The sub-prefecture of Dabiss is in the north-west of pebbles, deluvial-proluvial, marine silts, clays, and the Prefecture of Boké, between 11°00’ and 11°50’ sands. Figure 2 shows the geological map of the North latitude, 14°50’ and 14°75’ West longitude. It study area. is situated 37 km from the town of Boké, as the crow Tectonically, the study area is part of the sedimen- flies. According to Mamedov et al. (2010), Dabiss tary cover of the West African Craton and occupies consists of Paleozoic formations, which are repre- the entire part of the Bowé synclise. It has been sented by the Ordovician Pita suite (Opt), the affected by a fault that runs from southwest to north- Silurian Télemilé suite (Stl), and the Devonian Faro east (Bah, 2013). suite (Dfr). From a geomorphological point of view, the study a) Ordovician-Suite Pita (Opt): Ordovician deposits area belongs to two major geomorphological zones outcrop in the southwest of the Dabiss sub-prefecture (the coastal plain and the Fouta Djallon massif; in the coastal plain. They are represented by quartz Samozvantsev & Diallo, 1976): and oligomeric sandstones, often with oblique bed- a) The coastal plain: this occupies the western part ding, aleurolite lenses, gravelites and conglomerates. of the territory and constitutes a relatively flat surface. In the Republic of Guinea this suite is subdivided into It slopes slightly to the west and southwest and is five (5) sub-suites: Opt1; Opt2; Opt3; Opt4 and Opt5. formed by the valleys of the Cogon-Tinguilinta and The difference between the sub-suites is due to the their tributaries. granulometry. The grain size decreases from Opt1 to b) The Fouta Djallon massif: it forms a plateau Opt5. separated by the river valleys of Cogon and Tinguilinta b) The Silurian Suite Télemilé (Stl): Silurian depos- From a hydrogeological point of view, Dabiss pre- its outcrop in the southeast, center, and northwest of sents several types of aquifers. According to their the study area. They are represented by argillites and mode of recharge, it can be found (Togba, 1977): aleurolites. They have graptolite fossils. 4 A. M. DIALLO ET AL. Figure 2. Geological map of the study area. - The sandy-clay aquifers, allumino-feriginous, are Material and methods linked to the alteration crust. Field data collection - Silt-sand, sandy, and gravelly aquifers, linked to alluvial deposits. Sampling was carried out at eighteen (18) water - Dolerite aquifers and fissured gabbro-dolerite points in October 2018 across the villages. These aquifers linked to magmatic intrusions. drinking water samples were carried out and Figure 3. The localization of the study zone. (a) Localization of Dabiss area in Guinea; (b) localization of the study area in the Sub- Prefecture of Dabiss; (c) Presentation of the study area. GEOLOGY, ECOLOGY, AND LANDSCAPES 5 Table 1. Inventory of groundwater sampling points in the Dabiss study area. Geographical coordinates Well identification Villages X Y Well depth (m) PF1 Kaferé 14° 26’ 00,9” 11° 08’ 07,8” 73,07 PF2 Sambala 14° 27’ 31,6” 11° 04’ 55,3” 89,95 PF3 Kamsenhet 14° 26’ 18,7” 11° 04’ 19,9” 78,82 PF4 Togmaye 14° 31’ 31,4” 11° 02’ 22,4” 61,82 PF5 Kalounka Missidé 14° 30’ 04,3” 11° 06ʹ06,4” 72,91 PF6 Kamandé 14° 30’ 13,3” 11° 10’ 46,9” 67,23 PF7 Dikawé 14° 31’ 47,5” 11° 09’ 43,7” 63,46 PF8 Dabiss F2 AEP 14° 32’ 20,9” 11° 11’ 33,5” 50,55 PF9 Dapopo 14° 33’ 25,4” 11° 12’ 38,8” 84,20 PF10 Dabon 14° 35’ 53,3” 11° 06’ 33,4” 56,15 PF11 Thiankoun foulbé 14° 38’ 36,3” 11° 15’ 23,8” 61,90 PF12 Yenguekounia 14° 36’ 11,3” 11° 11’ 40,8” 56,10 PF13 Tomboya 14° 36’ 53,2” 11° 09’ 57,9” 73,06 PF14 Tambindjé 14° 33’ 16,1” 11° 14’ 09,1” 84,40 PF15 Wenseng II 14° 34’ 44,0” 11° 16’ 36,1” 67,49 PF16 Hafia 14° 36’ 31,0” 11° 17’ 17,2” 56,23 PF17 Mangodjé 14° 40’ 01,6” 11° 21’ 55,0” 56,20 PF18 Silibonty 14° 37’ 18,5” 11° 18’ 24,8” 56,29 analyzed in the laboratory by the National Water ID ¼ Dp� Dcþ Rp� Rcþ Ap� Acþ Sp� Sc Point Service (SNAPE). Figure 3 shows the locali- þTp� Tcþ Ip� Icþ Cp� Cc zation of the study zone. To facilitate data hand- (1) ling, a sample number was assigned to each sampling point as can be seen in Table 1. The Where Physico-chemical parameters (pH, temperature, D water depth, R effective recharge, A aquifer type, electrical conductivity, turbidity) were measured S soil type, T topography, I vadose zone, and in situ using a multi-parameter probe. Dissolved C hydraulic conductivity of the aquifer medium (Let oxygen was determined by the Winkler method D, R, A, S, T, I and C be the seven parameters of the (Rodier et al., 2009). The water levels were mea- DRASTIC method: p being the weight of the para- sured using a piezometric probe. The chemical meter and c the associated score). The results obtained analyzes of the major elements (cations and anions) from the DRASTIC index are presented in Table 2. were conducted by ion chromatography. Results Reference method A reference method is an official method recognized Physico-chemical parameters by international bodies that gives the most accurate Hydrogen potential (pH) result such as the closest to the true value of the The pH is one of the most significant parameters in concentration of a constituent under analysis. The acid-base geochemical water quality parameters. It is reference method usually gives the most accurate truly a measure of the relative quantity of free hydro- results, by composition with other methods of analysis gen and hydroxyl ions in the water. Water that holds of the constituent. In this study, we used the reference more free hydrogen ions is acidic and more free method. The results of the Physico-chemical analysis hydroxyl ions are basic. As pH can be affected by are interpreted by graphs concerning the World chemicals in the water, pH is a vital indicator of Health Organization (WHO) standard. In addition, water that is changing chemically. the bi-plot of Physico-chemical parameters, and the Figure 4 shows the pH of the groundwater in the spatial variations of water quality maps were generated study area. A total of 18 borehole samples were mea- using Excel and Inverse Distance Weighted (IDW) sured; out of them, 12 boreholes’ pH values were not interpolation technique using Arc GIS software, in the range recommended by WHO (6.5–8). Only 6 respectively. wells were within the pH range recommended by The DRASTIC method The method assesses vertical vulnerability based on 7 Table 2. DRASTIC vulnerability classification (Traore et al., different physical parameters that are involved in the 2016). transport and attenuation of contaminants. The Degree of vulnerability Vulnerability index Very low 0–84 DRASTIC vulnerability index (ID) is calculated as Low 85–114 the sum of the products of the scores and the weights Medium 115–145 of the corresponding scores (Panagopoulos et al., High 146–175 Very high 176–226 2006): 6 A. M. DIALLO ET AL. PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10PF11PF12PF13PF14PF15PF16PF17PF18 wells Variation of groundwater pH in the study area Figure 4. Variation of groundwater pH in the study area. Figure 5. The spatial variation of pH in the study area. WHO and exhibited the spatial variation of pH in the et al. (2014), Massally et al. (2017), and Dwirama Putra study area, as can be seen in Figure 5. et al. (2018), and Mali et al. (2020).The acidity of the Generally, groundwater in the study area is acidic. Low Dabiss groundwater was probably due to the acid-base pH groundwater favors the dissolution of metals into the reactions that resulted in the chemical composition of the groundwater system with remarkably high levels. The rocks that host the water. As a result of the action of groundwater, consequently, turns out to be unsafe for meteoric waters originally rich in carbonic acid HCO3, human drinking (Kortatsi, 2006; Shafiq et al., 2021). through the excavation, oxidation, and retention zones of Similar results of low pH values were also found by the lateritic clay cover, the capillary fringe receives acid several authors such as Ayantobo et al. (2013), Akil rainwater directly. This increased the H+ ion content and pH GEOLOGY, ECOLOGY, AND LANDSCAPES 7 weakens the pH, which becomes increasingly acidic. & Ayenew, 2016). From Figure 8, the current study Acidity in water is not in itself harmful to health. The showed that the EC value was between 15 µS/cm and concern for acidity in drinking water is that even mildly 567 µs/cm. acidic water can dissolve metals and other substances. From the spatial distribution of EC in Figure 9, it Consequently, acidic waters can negatively impact health can be viewed in general that EC values are low (low through the long-term development of respiratory alka- mineralization) in the study area. Comparing the EC losis, metabolic alkalosis, acido-respiratory and diabetic values obtained with the values in Table 3, it may say ketoacidosis pathologies (CIRA, 2018).Figure 6 shows the that, 7 wells (PF2; PF6; PF9; PF13; PF14; PF15, and relationship between Physico-chemical parameters in the PF16) were below 100 µS/cm, which indicates very low study area. There is an observable pattern of relationship mineralization; 8 other wells (PF1; PF4; PF5; PF8; between pH and Electrical Conductivity (EC; Figure 6b). PF10; PF12; PF17 and PF18) were in the range of The moderate positive correlation (r = 0.62) between pH 100–200 µS/cm, which shows low mineralization; and EC indicated that the EC decreases when the pH and 2 wells (PF7 and PF11) were ionized (in the decreases, but moderately. This interpretation should be range of 400–600 µS/cm) and were the level of ionic taken with caution because these two concepts are not concentration activity due to moderate dissolved related, and it is open to debate. Again, from Figure 6, the solids. This moderate mineralization in PF11 and pattern of the relationship between pH and other para- PF7 can be additionally observed in Figure 9. meters is not clear. From Table 1, the depths of the well (PF11 and PF7) were relatively deep; hence there will not be much contamination due to percolation. The average- Temperature (moderate) mineralization value in PF11 and PF7 Figure 7 shows the temperature of the groundwater in was possibly due to the presence of mineral salts in the study area, and it was relatively high during the the rocks crossed where they are dissolved by the sampling session, a period corresponding to the end of water during the transition, before reaching the the rainy season in the Republic of Guinea. These aquifer. temperatures were not showing great variations from one point to another, and this indicator is a function of the amount of dissolved oxygen. The minimum value Dissolved Oxygen (DO) was 26.5°C and the maximum value was 33.9°C for all Dissolved Oxygen (DO) level has a vital effect on samples. In general, the temperature in this study area groundwater quality by regulating the valence state was found within the permissible limit of WHO of trace metals and by constraining the bacterial meta- (30°C). A similar observation about temperature var- bolism of dissolved organic species (Rose & Long, iations was also as reported by Massally et al. (2017); 1988). DO levels provide important information and Dwirama Putra et al. (2018). Increased tempera- about the stability of many organic and inorganic ture values released a change in density, reduction in contaminants in groundwater. For these reasons, DO viscosity, and a decrease in the solubility of gases. It concentrations should be determined as part of most should be noted that water temperature has no direct groundwater quality monitoring surveys (Rose & impact on human health. Long, 1988). From Figure 6e, there is a visible pattern of relation- According to the WHO, DO levels should be main- ship between EC and temperature. EC was relatively tained as close to saturation as possible. There is no dependent on temperature (r = 0.42). As mentioned guidance value on health criteria (Prasad et al., 2014). by Mali et al. (2020), EC is affected by geology and In the absence of a Guinean and WHO standard, temperature, the warmer the water the higher the the Moroccan and French potability standards (70 and conductivity (Mali et al., 2020). Temperature affects 75% respectively) were used to qualify the water qual- the EC of water, because of the effect it has on the ity. Figure 10 shows the DO of the groundwater in the viscosity of water and the nature of ions (Saito et al., study area. The percentage of DO saturation in the 2016). Again, from Figure 6, the temperature did not wells of the study area is within the potability stan- show a clear relationship with other parameters. dards. From Figure 10, it was found that all DO values were low and their vary between 1.5 and 6.1%. DO Electrical conductivity (EC) shows a pattern of a relationship with temperature EC measures the ability of water to transmit an electric which is weak(r = 0.35; Figure 6h). It can be deduced current. Pure water is a poor electrical conductor. that temperature does not have a direct influence However, the ability of water to transmit electricity on DO. increases as the amount of dissolved solutes increases. Figure 8 shows the EC of the groundwater in the study Turbidity area. Table 3 shows the relationship between EC and Turbidity measurement is used to clarify visual informa- water mineralization. Referring to WHO standards, tion about the water. Turbidity reflects the presence of the EC value should not exceed 400 μS/cm (Meride suspended particles in the water for example, organic 8 A. M. DIALLO ET AL. (a) (b) (c) 7 8 7 1 1 0 5 10 0 500 1000 0 500 1000 PH EC (μs/cm) EC (μs/cm) (d) (e) (f) 140 40 20 5 5 0 500 1000 0 100 200 0 200 400 600 EC (μs/cm) Turbidity (NTU) EC (μs/cm) (g) (h) (i) 140 40 140 120 120 100 100 80 80 60 60 20 20 0 5 10 0 5 10 0 5 10 DO (mg/L) PH DO (mg/L) (j) 0 5 10 PH Figure 6. Relationship between physico-chemical parameters. (a) DO vs pH; (b); (b) pH vs EC; (c) DO vs EC; (d) Turbidity vs EC; (e) Temperature vs EC; (f) Temperature vs Turbidity; (g) Turbidity vs DO; (h) Temperature vs DO; (i)Turbidity vs pH; (j) Temperature vs pH. Turbidity (NTU) Turbidity(NTU) DO Temperature (C°) PH Temperature (C°) Temperature (C°) Temperature (C°) DO Turbidity (NTU) GEOLOGY, ECOLOGY, AND LANDSCAPES 9 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Wells Figure 7. Variation of groundwater temperature in the study area. PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Wells Electrical conductivity of the groundwater in the study area. Figure 8. Electrical conductivity of the groundwater in the study area. suspended particles in the water (turbid water). The sig- Table 3. Relationship between electrical conductivity and nificant presence of suspended particles is probably water mineralisation (Courtois & Béchennec, 1999). related to the geological nature of the subsoil, which is Conductivity in µs/cm, at 20°C Water mineralisation partly made up of bauxite mineralization. From <100 Very low mineralization Figure 6g, turbidity shows a pattern of a relationship 100–200 Low mineralization 200–400 Increased mineralisation with DO which is weak(r = 0.39; Figure 6h). It can be 400–600 Average mineralization said that turbidity does not have a direct influence on DO. 600–1000 High mineralization 1000 > Excessive mineralisation The results regarding the presence of anions and cations in the groundwater of the investigation area are summarized in Table 5. debris, clays, and microscopic organisms. Table 4 shows Major ions the common turbidity classification. According to the Anions WHO standard for turbidity of drinking water is 5 3- NTU. Figure 11 shows the turbidity of the study area. It Phosphates (PO ) was found that the turbidity values in 11 boreholes cor- In groundwater, various oxidized forms of phos- respond to the WHO values. Six (6) boreholes were phorus can be attached to ortho-phosphate, and the slightly turbid water and borehole PF6 contained a very analytical method did not allow them to be separated. high turbidity value. This means the presence of The ortho-phosphatic acid H PO can ionize in 3 4 Conductivity (μS/cm) Temperature (°C) 10 A. M. DIALLO ET AL. Figure 9. The spatial variation of electrical conductivity based on .Table 3 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Drilling wells Figure 10. Dissolved oxygen of the groundwater in the study area. Table 4. Common turbidity classification (NTU nephelometry levels in groundwater are often linked with turbidity unit). a natural decomposition of rocks and minerals, NTU < 5 Clear water and anthropogenic sources include; fertilizers, was- 5 < NTU < 30 Slightly cloudy water tewater and septic system effluent, and animal NTU > 50 Cloudy water waste (Fadiran et al., 2008). Deep groundwater suggests that natural geologic sources might have − −2 3- a greater influence on concentrations in ground- different ways. H PO ↔H PO ↔HPO ↔PO 3 4 2 4 4 4 water than anthropogenic sources (Welch et al., (Courtois, 2000). 3- 2010). Besides, the study area population is agro- PO concentrations, as shown in Table 5, vary 3- pastoral. The presence of significant amounts of from 0 to 1.34 mg/l. It was found that PO values 3- PO4 in PF3 may indicate the recent contamina- were lower than the WHO standard of 0.5 mg/l. tion resulting from natural and/ or anthropogenic Except for well PF3 (1.34 mg/l), which exceeds the 3- 3- sources. Naturally occurring levels of PO4 in WHO standard. PO are not very mobile in soils groundwater body is not dangerous to human and they are only moderately soluble. Its enhanced dissolved O (mg/l) 2 GEOLOGY, ECOLOGY, AND LANDSCAPES 11 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PF8 PF9 PF10 PF11 PF12 PF13 PF14 PF15 PF16 PF17 PF18 Drilling wells Figure 11. Turbidity of groundwater in the study area. Table 5. Major anion and cation ions present in the groundwater of the study area. 3 + 2 3+ 3+ 2+ Identifier PO₄ ⁻ (mg/L) NH₄ (mg/L) SO₄ ⁻ (mg/L) F⁻ (mg/L NO₃⁻ (mg/L) Al (mg/L) Cr (mg/L) Zn (mg/L) PF1 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF2 0,315 <1,0 <40 <0,1 <5 >0,5 0,048 <0,02 PF3 1,340 10,200 203 <0,1 <5 <0,02 <0,03 <0,02 PF4 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 0,046 PF5 <0,2 <1,0 <40 <0,1 <5 0,047 <0,03 <0,02 PF6 <0,2 <1,0 <40 <0,1 <5 0,049 <0,03 <0,02 PF7 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF8 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF9 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF10 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF11 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF12 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 0,087 PF13 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF14 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF15 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF16 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF17 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 <0,02 PF18 <0,2 <1,0 <40 <0,1 <5 <0,02 <0,03 0,285 OMS 0,5 2 250 1,5 50 0,2 0,03 3 mg/l 3- health. On the contrary, very high levels of PO4 250 mg/l, than the WHO standard for the quality of can cause digestive problems (Fadiran et al., 2008). water intended for consumption. Nitrate (NO ) Fluoride (F ) Nitrate is an important parameter in water and it is One of the most important elements in drinking water a naturally occurring inorganic ion present in our related to health is fluoride. This is in the form of environment. NO comes from the complete oxida- fluoride ions (F ). Fluoride in water comes mainly tion of organic nitrogen under the action of nitrifying from the dissolution of natural minerals in rocks and bacteria and nitrates from the incomplete oxidation soils with which the water reacts. Fluoride concentra- under the action of Nitrosomonas (Hamsatou, 2005). tions below 0.5 mg/l in drinking water can promote NO in groundwater is a primary indicator of anthro- tooth decay. At very high concentrations exceeding pogenic pollution. In the study area, low values of 1.5–2 mg/l, fluoride in drinking water can cause dental NO than that of the WHO standard of 50 mg/l or bone fluorosis and other skeletal (Matini et al., (Table 5) and indicated the absence of nitrogenous 2009). fertilization in the land surrounding the points stu- According to the result of the analysis of our sam- died. Consequently, these waters were not polluted ples in Table 5, the fluoride levels vary from 0 to with NO . 0.1 mg/l and are below than the WHO standard (1.5 mg/l). This showed that the waters were not 2- −. Sulphates (SO ) polluted with F Similar results were found by Sulfate is a major anion in most groundwater. Ayantobo et al. (2013); Massally et al. (2017) and According to the results of the samples analyzed as they stated that groundwater might be due to its acidic can be seen in Table 5, the values were not exceeded nature which renders it immobile. The F in the Turbidity (NTU) 12 A. M. DIALLO ET AL. analyzed waters could come from the dissolution of PF2 could be explained by the acidity of the water silicates. Since the F-ion has the same ionic radius as (acid water can increase the solubility of heavy the OH-ion, it could therefore be substituted for it in metals). Note that; Figure 4 showed that the pH of these minerals (Matini et al., 2009). the water in the well PF2 was 4.2 lower than 5. In other words, the Al-rich ground through which the well was drilled could be the cause of this high concentration. Cation Ammoniacal nitrogen (NH ) 3+ Chromium (Cr ) Ammoniacal nitrogen is present in toxic form (NH ). 4 3+ Cr which is one of the so-called toxic substances can Its presence in water usually reflects a process of be found in the water table due to human activities incomplete degradation of the organic matter. NH , such as the textile industry. Tanneries and explosives is transformed rather quickly into nitrite by oxidation 3+ are also anthropogenic sources of Cr , as well as (Hamsatou, 2005). In the study area, NH levels vary domestic waste buried in the subsoil without (Table 5) from 0 to 10.2 mg/l. Comparing these values 3+ a protective perimeter. Cr has two oxidation states to the WHO permissible value of 2 mg/l, borehole PF3 (+III and +IV) of which the more soluble, mobile form shows a value (10.2 mg/l) higher than the norm. Note and therefore the most toxic is hexavalent chromium 3- that, Well PF3 showed higher PO concentration. (Matini et al., 2009). 3- High PO concentrations in groundwater are gener- As can be seen in Table 5, the analysis shows low ally linked with high ammonia, near neutral pH, and 3+ levels of Cr and below than the WHO standard of anoxic conditions (Griffioen, 2006). Agricultural 3+ 0.03 mg/l. The Cr values of the sampled boreholes activity is a potential source of NH4. The population were between 0 and 0.048 mg/l. In this sense, it may in Dabiss is essentially agro-pastoral. The presence of conclude here that the groundwater in the study area the high NH + value in the well PF3 may be due to 4 3+ was away from Cr pollution. farmer activity. Interpretation of DRASTIC parameters and 2+ Zinc (Zn ) production of vulnerability maps 2+ Zn , like copper, is a trace metal element in magmatic The DRASTIC map presents a view of the relative rocks. It can be found in oxygenated waters rich in degree of vulnerability of a study area. The potential 2+ iron and manganese. Zn , can be of anthropogenic for pollution increases with the index (Latifi & Chaab, origin, through leaching from urbanized and indus- 2017). The partial index maps were obtained from trialized areas (Courtois, 2000). geological, topographical, hydrogeological, pedologi- 2+ The Zn , content of all the water varied from 0 to cal, hydrodynamic, and hydroclimatic data (Latifi & 0.28 mg/l (Table 5). All the values found in this ana- Chaab, 2017). This allowed the definition of the seven lysis were within the WHO standard (3 mg/l). This can (7) DRASTIC parameters. The distribution of index be explained by the geological nature of the terrain values for each parameter (weight×highest) is repre- through which the water flows. The presence of this sented on a map. Sectors with a high risk of pollution metallic element in the study area groundwater is not have strong coastlines and those with less risk have dangerous for consumption. a low value. The synthesis map of the vulnerability to pollution of the aquifer was obtained by making the 3+ weighted sum of the partial index values of the seven Aluminium (Al ) (7) DRASTIC parameters. There are several possible reasons for the contamina- 3+ tion of groundwater by Al : the soil through which 3+ 3+ the water flows are rich in Al and Al of industrial Depth to water table parameter “D” 3+ origin (Kholtei et al., 2003). On the other hand, Al is a trace element that only exists in solution in the The depth to water table defines the thickness of the 3+ exchangeable form Al , when the acid pH is below 5 aeration zone materials through which a contaminant (Courtois, 2000). The 18 water samples in the study percolates before reaching the groundwater. area were analyzed and found that only borehole PF2 Generally, attenuation capacity increases with depth shows a value above than the WHO drinking water (Latifi & Chaab, 2017). standard (0.2 mg/l). This result can be seen in Table 5. In the case of the present study, the depth of the 18 A similar finding was reported by Ayantobo et al. boreholes drilled varies from 50.55 to 89.95 m above (2013); Kusin et al. (2017). Bauxite is an aluminous 31 m, giving us a partial vulnerability index of order 5 rock that contains hydrated aluminium oxide as (Table 6). The index calculated in this way was used to 3+ a major constituent. The high Al value in borehole draw up the corresponding map (Figure 12). GEOLOGY, ECOLOGY, AND LANDSCAPES 13 Figure 12. Map of the depth parameter “D.” Figure 13. Map of net recharge parameter “R.” Parameter of the net recharge “R” The observation of the recharge map (Figure 13) shows that the infiltration was the same over the whole The recharge of the water table comes mainly from the study area. The calculation of the water balance gave direct infiltration of rainwater through the permeable an average value of effective infiltration estimated at layers and runoff water, or floods in the beds of tribu- 89.93 cm, in a range above 25 cm with a partial index taries (Latifi & Chaab, 2017). of 36. This parameter is reported in Table 7. 14 A. M. DIALLO ET AL. Table 8. Aquifer type parameter. Table 6. Parameter of the depth of the water table. Nature of the aquifer “A” Depth of the water table “D” Nature of the aquifer environment Score Partial index Interval (m) Score Partial index Shale 2 6 >31 01 05 Weight: 03 Weight: 05 an index of 18; Silts soils have an index of 8; and Clay an index of 6 (see, Table 9). Table 7. Recharge parameter. Net recharge “R” Interval (cm) Score Partial index Topographical parameter “T” >25 09 36 The slope of the land has a direct influence on the con- Weight: 04 centration time of the pollutants. It controls some para- meters such as infiltration (Latifi & Chaab, 2017). Parameter of the nature of the aquifer “A” Examination of the topographic map of the region reveals three (3) types of slope (Figure 16). The Topographic The determination of this parameter results from the parameters can be seen in Table 10. borehole data (Latifi & Chaab, 2017). The nature map of the aquifer (Figure 14) is characterized by shale, throughout the study area. The index calculated in Parameter impact of the unsaturated zone “I” Table 8 is equal to 6. The impact of the unsaturated zone (aeration zone) is a very important parameter in the application of the DRASTIC method. This parameter was studied based Parameter nature of soil type “S” on the nature of the lithology of the study area (Traore This parameter has an impact on the fringe of water that et al., 2016). The nature and thickness of the part penetrates through the soil to reach the water table. In between the soil surface and the aquifer control to other words, it is the vertical migration of pollutants some extent the vulnerability to groundwater pollu- through the saturated zone (Latifi & Chaab, 2017). The tion (Latifi & Chaab, 2017). The map of the unsatu- soil type map (Figure 15) shows sand, silts, and clay soils. rated zone (Figure 17) shows clay and shale. The Sand soils have corresponding index is mentioned in Table 11. Figure 14. Map of aquifer nature parameter. GEOLOGY, ECOLOGY, AND LANDSCAPES 15 Figure 15. Soil type parameter map. Table 9. Soil type parameter. Hydraulic conductivity parameter “C” Soil type parameter The permeability coefficient map is drawn up by Nature of the soil Score Partial index pumping tests in the different boreholes. The perme- Sand 9 18 Silts 4 8 ability coefficient reflects the speed at which water, Clay 3 6 transports the pollutant by dispersion in the subsoil Weight: 02 (Latifi & Chaab, 2017). The index of this parameter is Figure 16. Topographic parameter map. 16 A. M. DIALLO ET AL. Figure 17. Unsaturated zone parameter map. Table 10. Topographic parameter. indices (Latifi & Chaab, 2017). With the application of Topographic parameter the DRASTIC method, we obtained a vulnerability index equal to ninety-four (94). According to the Intervals (%) Score Partial index classification of the US Environmental Protection 2–6 9 9 6–12 5 5 Agency, as shown in Table 2, the vulnerability index 12–18 3 3 of our study area is in the range of 85–114. Weight: 01 A reading of the vulnerability map (Figure 19) shows that the groundwater in the study area has Table 11. Unsaturated zone parameter. a low vulnerability. This is explained by the reduction Impact of the unsaturated zone “I” in the propagation of the pollutant due to the texture and structure of the rocks in the vadose zone, the Nature of the unsaturated zone Score Partial index Clay 1 5 depth of the aquifer, the slopes, and the permeability Shale 3 15 of the overlying layers. Weight:05 Limitations and future work reported in Table 12. The observation of the hydraulic conductivity map (Figure 18) shows that the conduc- It is important to emphasize that the results of this tivity was the same over the whole area. study are only generalized to the Dabiss South area in and around the mine concession. Despite the study exposing good water quality for most para- The vulnerability map meters, all areas of Dabiss were not investigated which is noted to be one of the limitations of the The vulnerability map of the water table allows visua- investigation. The limitation is also due to a lack of lizing the main risk areas which are related to high hydrogeochemical data over a long period based on advanced analytical chemical methods such as the Table 12. Hydraulic conductivity parameter. Inductively Coupled Plasma-Mass Spectrometer Hydraulic conductivity “C” (ICP-MS). Intervals (m/s) Score Partial index However, the results gained from this research −7 −5 4,72 × 10 -4,01 × 10 1 3 for the first time would be a guideline for future Weight: 03 research in the prefecture of Boke. For a depth GEOLOGY, ECOLOGY, AND LANDSCAPES 17 Figure 18. Hydraulic conductivity parameter map. Figure 19. Vulnerability map of the study area. analysis of water quality in the Dabiss area, the research. Different sampling campaigns should be monitoring and analysis should be done for carried out in all Dabiss areas. Test samples (raw a longer period of time. The minimum time for ore, soils, discharges, surface water, and ground- such monitoring should be one year to obtain water) should be collected for analysis and bauxite a series of data that confirm the reliability of the mining tests in the laboratory. 18 A. M. DIALLO ET AL. Volume13/4-Water-Quality-Evaluation-of-Hand-Dug. Conclusion pdf Bah, I. L. (2013) Etude des fossiles caracteristiques de la In this work, we analyzed groundwater vulnerability to feuille Kandiafara. Mémoire de diplôme de fin d’etude pollution in the sub-prefecture of Dabiss, one of the superieure, Institut Superieur des Mines et Geologie de bauxite mining areas of the Boké Prefecture. In sum- Boke. ISMGB. mary, the following observations were made when Bakouan, C., Guel, B., & Hantson, A.-L. (2017). Caractérisation physico-chimique des eaux des forages analyzing the Physico-chemical parameters of the des villages de Tanlili et Lilgomdé dans la région Nord water samples and the DRASTIC vulnerability map. du Burkina Faso - Corrélation entre les paramètres phy- The majority of the groundwater in the study area sico-chimiques. Afrique SCIENCE, 13(6), 325–337. seems to be acidic. In our case, the acidity of these https://www.afriquescience.net/PDF/13/6/27.pdf waters is probably explained by an in-situ Barbulescu, A. (2020). Assessing Groundwater phenomenon. Vulnerability: DRASTIC and DRASTIC-Like Methods: A Review. Water, 12(5), 1356. https://doi.org/10.3390/ In the study area, most of the groundwater from w12051356 drinking wells analyzed is complying with WHO stan- Batchi, M., Al Kalkouri, J., Fenjiro, I., & El Maaqili, M. dards. It was found that a low vulnerability of ground- (2017). Etude comparative de deux modèles (DRASTIC water in the study area. et SI) pour l'évaluation de la sensibilité de la nappe The outcomes gained from this research may be phréatique de Mnasra (Nord-Ouest Marocain) à la pollu- tion d'origine agricole. Physio-Géo, 11, 43–64. https://doi. improved by incorporating other social, and ecological org/10.4000/physio-geo.5213 factors, as well as the use of mathematical modeling to Campbell, B., & Hatcher, P. (2019). Neoliberal reform, con- improve the model efficiency. testation and relations of power in mining: Observations From the above, the study recommends that the from Guinea and Mongolia. The Extractive Industries and SMB mining company should develop water- Society, 6(3), 642‑653. https://doi.org/10.1016/j.exis.2019. monitoring programs by collecting water samples for 06.010 Chen, X., 1, Li, X., 2, Wu, P., 3, Xuefang, Z., 4, Yabin, L., 5, laboratory analysis or by using probes so that mine Tao, W., 6, & Wenrui, R. (2022). The development and operators can gauge the impact that their mine was utilization of bauxite resources in the Guizhou Province having on the local environment. It will reveal the and relevant challenges to the ecology and the quality and composition of groundwater and surface environment. Gospodarka Surowcami Mineralnymi - water over time, as well as over weeks, months, and Mineral Resources Management, 38(2), 5–30. https://doi. org/10.24425/gsm.2022.141667 years. Besides, SMB should grant agricultural inputs CIRA. (2018). Étude de caractérisation environnementale et free of persistent organic pollutants to a farmer, and sociale des activités minières en cours. Rapport du Projet also train them in agricultural techniques up to the d'Alimentation en Eau Potable et d'Assainissement dans marketing of products from their plains. Finally, SMB les Préfectures de Boké et de Télimélé (PAEPA-BT). and the entire community should be educated on the Courtois, N. (2000). Ressources en eaux soutet~aincs en zone health risk linked with human exposure to water de socle de la Vendée -. Aspects qualitatifs. BRGM. http:// infoterre.brgm.fr/rapports/RP-50394-FR.pdf pollution. Courtois, N., & Béchennec, F. (1999). Groundwater resources in the Vendée basement zone. BRGM. Dresse, A., Nielsen, J. Ø., & Fischhendler, I. (2021). From Disclosure statement corporate social responsibility to environmental peace- building: The case of bauxite mining in Guinea. Resources No potential conflict of interest was reported by the Policy, 74, 102290. https://doi.org/10.1016/j.resourpol. author(s). 2021.102290 Ducommun, R., 2010. Estimation and mapping of ground- References water vulnerability in urban areas (PhD Thesis). University of Neuchâtel. Dwirama Putra, R., Apriadi, T., Suryanti, A., Irawan, H., Affandi, F. N. A., Kusin, F. M., Sulong, N. A., & Madzin, Z. Said Raja, T., & Yulianto, T.(2018) Preliminary study of (2018). Hydrogeochemical assessment of mine-impacted heavy metal (Zn,Pb, Cr, As, Cu, Cd) contaminations on water and sediment of iron ore mining. IOP Conference different soil level from post-mining bauxite production Series: Earth and Environmental Science, 140 (1), 012023. for aquaculture, SCiFiMaS 2018, E3S Web of Conferences IOP Publishing.https://doi.org/10.1088/1755-1315/140/ 47, 02008, https://doi.org/10.1051/e3sconf/20184702008 1/012023 Ewodo Mboudou, G., Auguste, O., Bon, A. F., Ntep, F., & Akil, A., Hassan, T., Fatima, E.H., Lahcen, B., Abderrahim, Bineli, E. (2016) Apport des méthodes paramétriques L., (2014). Etude de la qualité physico-chimique et con- DRASTIC, GOD et SI à l’évaluation de la vulnérabilité tamination métallique des eaux de surface du bassin ver- intrinsèque dans les aquifères du bassin versant de sant de guigou, maroc. European Scientific Journal, ESJ, l’abiergué (région de Yaoundé). Science de la vie, de la 10(23). https://doi.org/10.19044/esj.2014.v10n23p%p terre et agronomie,Revue CAMES, 4, 67–78. ISSN 2424- Ayantobo, O. O., Oluwasanya, G. O., Idowu, O. A., & 7235 file:///C:/Users/p/Downloads/R%C3%A9sum%C3% Eruola, O. A., (2013). Water quality evaluation of hand- A9.%20Abstract.%20EWODO%20MBOUDOU% dug wells in ibadan, oyo state, Nigeria. Global Journal of 20Guillaume%201,%202_,%20OMBOLO%20Auguste% Science Frontier Research Agriculture and Veterinary, 13 201,%20BON%20Andr%C3%A9%20Firmin%202,%203, (10) Version 1.0. https://globaljournals.org/GJSFR_ GEOLOGY, ECOLOGY, AND LANDSCAPES 19 %20NTEP%20Fran%C3%A7ois%202,%20BINELI% Dist-Kolhapur, Maharashtra State, India. International 20Etienne%203.pdf. ,%4_,%20OMBOLO%20Auguste% Research Journal of Environment Sciences, 4, 77–83. 201,%20BON%20Andr%C3%A9%20Firmin%202,%203, Latifi, S., & Chaab, S. (2017). Evaluation and mapping of %20NTEP%20Fran%C3%A7ois vulnerability to groundwater pollution, using DRASTIC Fadiran, A. O., Dlamini, S. C., & MavusoBull, A. (2008). and GOD methods, in the alluvial plain of Guelma, A comparative study of the phosphate levels in some North-East Algeria. Reviesed Science Technolgy Synthese, surface and groundwater bodies of Swaziland Chem. 34, 48–62. https://www.ajol.info Society of Ethiopia, 22(2), 197–206. https://doi.org/10. Lee, K. Y., Ho, L. Y., Tan, K. H., Tham, Y. Y., Ling, S. P., & 4314/bcse.v22i2.61286 Qureshi, A. M. (2017). Environmental and occupational Frost-Killian, S., Master, S., Viljoen, R. P., & Wilson, M. G. health impact of bauxite mining in Malaysia: A Review. (2016). The great mineral fields of Africa introduction. IIUM Medical Journal Malaysia, 16(2). https://doi.org/10. Episodes Journal of International Geoscience, 39(2), 85– 31436/imjm.v16i2.346 103. https://doi.org/10.18814/epiiugs/2016/v39i2/95770 Machiwal, D., Jha, M. K., Singh, V. P., & Mohan, C. (2018). Griffioen, J. (2006). Extent of immobilization of phosphate Assessment and mapping of groundwater vulnerability to during aeration of nutrient-rich, anoxic groundwater. pollution: Current status and challenges. Earth-Science Journal of Hydrology, 320(3–4), 359–369. https://doi. Reviews, 185, 901–927. https://doi.org/10.1016/j.ear org/10.1016/j.jhydrol.2005.07.047 scirev.2018.08.009 Hamsatou, M. M. D., 2005. University of Bamako, p. 135. Mali, S. C., Thabaj, K. A., & Purandara, B. K. (2020). He, H., Li, X., Li, X., Cui, J., Zhang, W., & Xu, W. (2018). Evaluation of geochemical characteristics of groundwater Optimizing the DRASTIC method for nitrate pollution in in parts of ghataprabha sub-basin using DRASTIC groundwater vulnerability assessments: a case study in indices. Journal of the Geological Society of India, 95(5), China. Polish Journal of Environmental Studies, 27(1), 513–519. https://doi.org/10.1007/s12594-020-1470-8 95–107. https://doi.org/10.15244/pjoes/75181 Mamedov, V. I., Bouféév, Y. V., Nikitine, Y. A., & Human Rights Watch., 2018 « Quels bénéfices en tirons-nous Mamedov, A. I. (2010). database of useful mineral deposits ? » Impact de l’exploitation de la bauxite sur les droits and indices/Ministry of Mines and Geology Rep. of Guinea. humains en Guinée. https://www.hrw.org/sites/default/ GEOPROSPECTS Ldt; Univ. e of Moscow State files/report_pdf/guinea1018fr_web.pdf Lomonosov (Fac. Geol)-Conakry-Moscow. Institut National de la Statistique (INS)., 2016. Annuaire Massally, R.-E. M., Sheriff, A. B., Kaitibi, D., Abu, A., statistique, République de Guinée, p. 50. Barrie, M., & Taylor, E. T. (2017). Comprehensive assess- Keita, M., & Traore, O. (2020). Environmental impact of ment of groundwater quality around a major mining Open PIT Mining: Case of Bauxite Mining in Guinea - company in Southern Sierra Leone. Journal of Water A Review -. International Journal of Applied Resource and Pro- Tection, 9(6), 601–613. https://doi. Environmental Sciences, 15 (2), 167–177. https://www. org/10.4236/jwarp.2017.96040 ripublication.com/ijaes20/ijaesv15n2_01.pdf 09736077 Matini, L., Moutou, J. M., & Kongo-Mantono, M. S. (2009). 09736077 Hydro-chemical evaluation of groundwater in an urban Kholtei, S., Bouzidi, A., Bonini, M., Fekhaoui, M., Sbai, K., environment in the southwest of Brazzaville, Congo. Anane, R., & Creppy, E. E. (2003). Contaminations des African Journal of Science and Technology, 5. https://doi. eaux souterraines de la plaine de Berrechid dans la région org/10.4314/afsci.v5i1.61709 de Chaouia, au Maroc, par des métaux présents dans les Meride, Y., & Ayenew, B. (2016). Drinking water quality eaux usées : Effet de la pluviométrie. Eaux Souterraines. assessment and its effects on residents health in Wondo Vecteur Environ, 36, 68. https://www.researchgate.net/ genet campus, Ethiopia. Environmental Systems Research, profile/Fekhaoui-Mohamed/publication/259674788_arti 5(1). https://doi.org/10.1186/s40068-016-0053-6 cle_kholti_et_al/links/0046352d48c8d82403000000/arti Moe, C. L., & Rheingans, R. D. (2006). Global challenges in cle-kholti-et-al.pdf water, sanitation and health. Journal of Water and Health, Kitula, A. G. N. (2006). The environmental and 4(S1), 41–57. https://doi.org/10.2166/wh.2006.0043 socio-economic impacts of mining on local livelihoods Neha Gupta. (2014). Groundwater Vulnerability in Tanzania: A case study of Geita District. Journal of Assessment using DRASTIC Method in Jabalpur Cleaner Production, 14(3‑4), 405‑414. https://doi.org/10. District of Madhya Pradesh. International Journal of 1016/j.jclepro.2004.01.012 Recent Technology and Engineering (IJRTE), 3(3). 2277– Knierzinger, J. (2014). The socio-political implications of 3878. https://www.ijrte.org/wp-content/uploads/papers/ bauxite mining in Guinea: A commodity chain v3i3/C1133073314.pdf \ perspective. The Extractive Industries and Society, 1(1), Nurroh, S., Totok gunawan, and Andri Kurniawan 20–27. https://doi.org/10.1016/j.exis.2014.01.005 Assessment of groundwater pollution risk potential Kortatsi, B. K. (2006). Concentration of trace metals in using DRASTIC Model in Yogyakarta City, Indonesia, boreholes in the Bassin d’Ankobra, Ghana. West African E3S Web of Conferences 200, 02002 (2020) DOI: https:// Journal of Applied Ecologyis, 10, 73–87. https://doi.org/10. doi.org/10.1051/e3sconf/202020002002 4314/wajae.v10i1.45706 Panagopoulos, G. P., Antonakos, A. K., & Lambrakis, N. J. Kusin, F. M., Rahman, M. S. A., Madzin, Z., Jusop, S., (2006). Optimization of the DRASTIC method for Mohamat-Yusuff, F., Ariffin, M., & Z, M. S. M. (2017). groundwater vulnerability assessment via the use of sim- The occurrence and potential ecological risk assessment ple statistical methods and GIS. Hydrogeology Journal, 14 of bauxite mine-impacted water and sediments in (6), 894–911. https://doi.org/10.1007/s10040-005-0008-x Kuantan, Pahang, Malaysia. Environmental Science and Prasad, B. S. R. V., Srinivasu, P. D. N., Varma, P. S., Pollution Research, 24(2), 1306–1321. https://doi.org/10. Raman, A. V., & Ray, S. (2014). Dynamics of dissolved 1007/s11356-016-7814-7 oxygen in relation to saturation and health of an aquatic Lad, R. J., & Samant, J. S. (2012). Impact of bauxite mining body: A case for Chilka Lagoon, India. Journal of Ecosystems, on soil: A case study of bauxite mines at Udgiri, 2014, 1–17. https://doi.org/10.1155/2014/526245 20 A. M. DIALLO ET AL. Rao, M. J., Prasad, C. H., Mohammad, M., Kakkassery, A. I., Journal of Agricultural and Biological Engineering, 11(2), et al. (2016). Bauxite mining in Eastern Ghats of Andhra 115–121. https://doi.org/10.25165/j.ijabe.20181102.2747 Pradesh, possible environmental implications and mea- Singh, V. S., Prasad, R. K., & Banerjee, P. (2010). sures for environmentally friendly mining. International Vulnerability of groundwater in an industrial (Bauxite) Journal of Science and Research, 5, 1434–1437. valley of Lanjigarh (Orissa), India. Environmental Earth Rodier, J., Legube, B., Merlet, N., & Brunet, R. (2009). Sciences, 60(8), 1739–1751. https://doi.org/10.1007/ L'analyse de l'eau - 9ème édition - Eaux naturelles, eaux s12665-009-0311-2 résiduaires, eau de mer: Eaux naturelles, eaux résiduaires, Souare, S. (2019). Bauxite mining in the Boké Region eau de mer (Technique et ingénierie). DUNOD Edition. (Western Guinea): method used and impacts on physical Rose, S., & Long, A. (1988). Monitoring dissolved oxygen in environment. European Journal of Sustainable ground water: some basic considerations. Groundwater Development Research, 3 (3), em0087. https://doi.org/10. Monitoring & Remediation, 8(1), 93–97. https://doi.org/ 29333/ejosdr/5735 10.1111/j.1745-6592.1988.tb00981.x Soumah, I. (2009). The future of mining industry in Guinea Saito, T., Hamamoto, S., Ueki, T., Ohkubo, S., Moldrup, P., (HARMATTAN), (January 1, 2009). Kawamoto, K., & Komatsu, T. (2016). Temperature Taazzouzte, M., Ghafiri, A., Lemacha, H., El Moutaki, S., & change affected groundwater quality in a confined marine Haidara, I. (2021). Mapping intrinsic vulnerability to aquifer during long-term heating and cooling. Water pollution using the DRASTIC method in the Temara Research, 94, 120–127. https://doi.org/10.1016/j.watres. Groundwater. Systems (IJAEIS), 12(4), 1–18. http://doi. 2016.01.043 org/10.4018/IJAEIS.293753 Samozvantsev, V., & Diallo, H. (1976). Etude géologique des Togba, M. (1977). Projet de prospection préalable des pla- feuilles Kandiafara et Koumbia à l’échelle 1/200000. teaux bauxitiques d’Aye-Koye (Boké). Mémoire de diplôme Société d’exploration géologique Féderation de Russie- de fin d’études supérieures. Institut Supérieur des Mines et Organisme de la recherche géologique. Géologie de Boké, ISMGB. Satouh, A., Boualem, B., Chellat, S., & Benaabidate, L. Traore, P. N., Djedi, H. M., & Khemmoudj, K. (Framer.), (2021). Determination of Groundwater Vulnerability 2016. Comparative study of groundwater vulnerability to Using the DRASTIC Method in Ouargla Shallow pollution in the commune of Souk El Tenine by DRASTIC Aquifer (Algerian Sahara). Journal of Ecological and GOD methods. Université A. MIRA. http://172.17.1. Engineering, 22(6), 12–19. https://doi.org/10.12911/ 105:8080/xmlui/handle/123456789/1022 (Accessed: 20 22998993/137680 January 2021) Shafiq, W., Ullah, H., Zaheer, M., Mehmood, M., Farooq, U., Welch, H. L., U, J. A. K., & Coupe, R. H. 2010 Occurrence of Khan, M. J., Ullah, S., & Ullah, S. (2021). Aquifer character- phosphorus in groundwater and surface water of north- ization and physiochemical analysis of District Dera Ghazi western Mississippi, Mississippi water resources conference Khan Punjab, Pakistan. Rudarsko-geološko-naftni zbornik, Xin, X., Wenxi, L., Leilei, Y., & Haibo, C., “Application 36(3), 47–57. https://doi.org/10.17794/rgn.2021.3.4 of DRASTIC method in groundwater vulnerability Shahab, A., Qi, S., Zaheer, M., Rashid, A., Talib, M. A., & assessment of Jilin City,” 2011 International Ashraf, U. (2018). Hydrochemical characteristic and water Symposium on Water Resource and Environmental quality assessment for drinking and agricultural purposes in Protection, 2011, pp. 286–289, https://doi.org/10.1109/ District Jacobabad, Lower Indus Plain, Pakistan. International ISWREP.2011.5893001.

Journal

Geology Ecology and Landscapes – Taylor & Francis

Published: Oct 29, 2022

Keywords: Groundwater vulnerability; groundwater pollution; Dabiss bauxite mining; Prefecture of Boké; Republic of Guinea

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