The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for...The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.展开更多
A bathymetric and sedimentological analysis carried out respectively in July 2017 and April 2018 made it possible to characterize the sediments and the morphology of Lake Nafoun. The sediments of the lake consist of v...A bathymetric and sedimentological analysis carried out respectively in July 2017 and April 2018 made it possible to characterize the sediments and the morphology of Lake Nafoun. The sediments of the lake consist of vases, fine to very coarse sands with average particle sizes ranging from 475.67 and 2111 μm. There is a predominance of very coarse elements (43.50%). The standard deviation of the lake sand is between 1.21 and 1.86 and is poorly classified. The skewness fluctuates between ?0.06 and 0.41. The sediments were deposited at the bottom of the lake due to a progressive decline in the flow of water that carried them. Moreover, this study made it possible to realize the first bathymetric chart of Lake Nafoun, 42 years after its impoundment in 1975.展开更多
This study aims to examine the quality and quantity of the groundwater resources from hand-dug wells, within two of these slums—Anoumabo (Marcory) and Adjouffou (Port-Bouet), both located in the southern part of the ...This study aims to examine the quality and quantity of the groundwater resources from hand-dug wells, within two of these slums—Anoumabo (Marcory) and Adjouffou (Port-Bouet), both located in the southern part of the city. Twenty-eight representative groundwater samples were collected from different domestic wells within the study area. In addition, water samples were collected from the adjoining surface water bodies—the ébrié lagoon and the Atlantic Ocean. The water samples were also tested for microbial indicators of fecal contamination using the conventional membrane filtration method. The groundwater samples are alkaline to acidic with pH ranging between 4.4 and 8.1. They are slightly mineralized with electrical conductivity, EC values ranging between 388 μS/cm and 1494 μS/cm. The dominant hydrochemical facies are Na-Cl, Na-SO4, Ca-Cl and Ca-SO4. Although, majority of the water samples have anions and cations concentrations conforming to the World Health Organization, alerting levels of nitrate contamination was recorded in the area. About 67 percent of the tested samples have nitrate values greater than the recommended WHO limit for drinking water (NO3 > 50 mg/ι). Exceeding high nitrate concentrations in drinking water have been medically proven to be detrimental to infant health. Microbial analyses reveal bacterial contamination at varying degrees in all of the water wells. The presence of these microbial organisms in the samples is also indicative of the presence of some other disease causing pathogens, responsible for sicknesses like cholera, diarrhea, typhoid, etc. The water wells located within Anoumabo have relatively higher levels of groundwater contaminants in comparison to those located within Adjouffou. This is obviously due to the poor well designs and prevalent unhygienic and poor sanitary habits of its inhabitants. These waters though completely unsuitable for drinking and domestic purposes, can be used for irrigation purposes with very little or no sodium problems.展开更多
文摘The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.
文摘A bathymetric and sedimentological analysis carried out respectively in July 2017 and April 2018 made it possible to characterize the sediments and the morphology of Lake Nafoun. The sediments of the lake consist of vases, fine to very coarse sands with average particle sizes ranging from 475.67 and 2111 μm. There is a predominance of very coarse elements (43.50%). The standard deviation of the lake sand is between 1.21 and 1.86 and is poorly classified. The skewness fluctuates between ?0.06 and 0.41. The sediments were deposited at the bottom of the lake due to a progressive decline in the flow of water that carried them. Moreover, this study made it possible to realize the first bathymetric chart of Lake Nafoun, 42 years after its impoundment in 1975.
文摘This study aims to examine the quality and quantity of the groundwater resources from hand-dug wells, within two of these slums—Anoumabo (Marcory) and Adjouffou (Port-Bouet), both located in the southern part of the city. Twenty-eight representative groundwater samples were collected from different domestic wells within the study area. In addition, water samples were collected from the adjoining surface water bodies—the ébrié lagoon and the Atlantic Ocean. The water samples were also tested for microbial indicators of fecal contamination using the conventional membrane filtration method. The groundwater samples are alkaline to acidic with pH ranging between 4.4 and 8.1. They are slightly mineralized with electrical conductivity, EC values ranging between 388 μS/cm and 1494 μS/cm. The dominant hydrochemical facies are Na-Cl, Na-SO4, Ca-Cl and Ca-SO4. Although, majority of the water samples have anions and cations concentrations conforming to the World Health Organization, alerting levels of nitrate contamination was recorded in the area. About 67 percent of the tested samples have nitrate values greater than the recommended WHO limit for drinking water (NO3 > 50 mg/ι). Exceeding high nitrate concentrations in drinking water have been medically proven to be detrimental to infant health. Microbial analyses reveal bacterial contamination at varying degrees in all of the water wells. The presence of these microbial organisms in the samples is also indicative of the presence of some other disease causing pathogens, responsible for sicknesses like cholera, diarrhea, typhoid, etc. The water wells located within Anoumabo have relatively higher levels of groundwater contaminants in comparison to those located within Adjouffou. This is obviously due to the poor well designs and prevalent unhygienic and poor sanitary habits of its inhabitants. These waters though completely unsuitable for drinking and domestic purposes, can be used for irrigation purposes with very little or no sodium problems.
