Geochemical assessment of impact of mine spoils on the quality of stream sediments within the Obuasi mines environment, Ghana (original) (raw)
Related papers
Journal of environmental science and pollution research, 2016
Trace metal concentrations in water and sediment samples collected from six rivers in some artisanal and small-scale gold mining sites at Tarkwa-Nsuaem Municipality in the Western Region of Ghana were studied. A total of 70 water and sediment samples were analysed for Mercury (Hg), Arsenic (As) Lead (Pb), Cadmium (Cd), Zinc (Zn), Copper (Cu) and Manganese (Mn) using Atomic Absorption Spectrometry (AAS). Four out of the seven trace metals, namely, Hg, As, Pb and Cd in all the water samples examined exceeded their respective WHO maximum acceptable limit in drinking water. In order of decreasing ecological threat, the trace metals investigated can be arranged in the following order: Hg>Cd>As>Cu>Pb>Zn>Mn. The Geo-accumulation index (Igeo) and Contamination factor (Cf) values of sediment indicate that all the rivers studied were heavily contaminated (3<Igeo≤4) and uncontaminated to moderately contaminated (0<Igeo≤1) with Hg and Cd respectively. The strong correlation between Hg, As and Cd concentrations in water and sediment samples showed the possibility of sediment acting as a secondary pollution source. High Potential Ecological Risk (PER) index values (332.67≤RI≤649.03) were recorded for the six rivers studied suggesting possible detrimental effect on the health of inhabitants of the community who depend on the rivers for drinking water without prior treatment.
American Journal of Engineering and Applied Sciences, 2018
The illegal gold mining activities prevalent in most part of Ghana have caused substantial havoc to the environment especially water bodies which serve as sources of water for domestic, industrial and agricultural purposes. The Ghana Water Company Limited (GWCL) recently shut down their water treatment plant due to the extreme pollution and high cost of treatment. This study focusses on the impact of mining activities on water quality of the affected water bodies, to assess the level of pollution of the river sediments and the extent of dispersion of the heavy metallic pollutants and to map out areas within the Konongo Municipality where illegal mining activities are prevalent. In this regard, both water and sediment samples from two rivers namely; Owerri and Asuokofi in Konongo (in the Asante Akim Central Municipality) were collected at different locations and analysed using Flame Atomic Absorption Spectrometry (FAAS) to assess the concentrations and dispersions of metallic pollutants. Geographical Positioning System (GPS) coordinates of these sample locations were also taken for mapping the sampling points and area. Four different metals; mercury (Hg), Lead (Pb), Arsenic (As) and Cadmium (Cd) were analysed. For sediments, the mean levels of Pb, Hg, As and Cd for the owerri river were found to be 52.2±2, 0.3±0.5, 492±365 and 1.7±2.0 mg kg −1 respectively; whilst those for Asuokofi river were 12±0.7, 2.7±0.4, 21.2±13.5 and 1.6±0.4 mg kg −1 respectively. The mean levels of Pb, Hg, As and Cd for water of the owerri river are respectively 2.5±3.7, 0.20±0.4, 0.28±0.2 and 3.1±0.4 mg L −1 ; whilst those for Asuokofi river were 8.2±1.3, 2.3±1.8, 25.4±22.2 and 0.45±0.7 mg L −1 respectively. Comparing these levels with the WHO standards for water discharges, these concentrations far exceeded the recommended values. This will impact negatively on the quality of both rivers with dire consequences since they serve as the main raw water resource for drinking water production. Samples of sediments and water from the upstream of these rivers where no activity of alluvial mining is taken place were recorded and they showed lower levels of these metals. It can therefore be concluded that the activities of alluvial gold mining in the study area impacts negatively on both the quality of water in the river and the sediments thereof.
The aim of the study was to spatially assess the distribution of heavy metals within the catchment of the Tarkwa mining area using interpolation techniques in a geographical information systems environment. Water quality trends for 84 sites in Tarkwa, a mining district in Ghana, were examined for fourteen (14) parameters-pH, conductivity, Total Dissolved Solids (TDS), turbidity, nitrates, sulphates, Chemical Oxygen Demand (COD), total cyanides, arsenic (As), cadmium (Cd), iron (Fe), manganese (Mn), nickel (Ni) and lead (Pb). Kriging was utilized to illustrate the spatial patterns of variables. The results showed that surface and groundwater are contaminated by As, Cd, Fe, Mn and Pb with the average concentrations exceeding World Health Organisation guideline values. The spatial dependence of the heavy metals was assessed using variogram parameters which varied from 320.30 to 4842.25 m. Significant correlations were found among heavy metals, which suggest a common origin. This is confirmed by the cluster analysis which indicated that Fe, As and Pb belonged to one group. The use of geostatistical tools in water quality assessment in this study enhances our understanding of spatial trends.
Universal Journal of Geoscience
The geochemistry of surface soils and stream sediments from the Birnin-Gwari area in the northwestern Nigeria Schist Belt was studied in order to assess the environmental impact of small-scale artisanal mining of quartz-gold-sulfide mineralization. Total elemental concentration was measured using X-ray fluorescence spectrometry. The results show elevated concentrations of silica, zirconium and paucity of base cations due to intense tropical weathering, accompanied by removal of fine labile fractions by wet season flooding and dry directional winds. This has implication for water chemistry in the area, especially with respect to pH due to low buffering capacity. The results further show that artisanal mining has not caused severe potentially toxic elements contamination. The consistently higher arsenic concentrations, relative to baseline values, were found not to vary between the mine-impacted and background areas. It is therefore interpreted to have been contributed by the use of agrochemicals in the area. The study has not found a significant human health risk associated with potentially toxic element uptake from mine wastes. It is however recommended that the distribution of arsenic in the soils, sediments and surface water in the area should be further studied in order to ascertain the sources and possible human health implications.
… Science and Health, …, 2010
The levels of heavy metals in surface water and their potential origin (natural and anthropogenic) were respectively determined and analysed for the Obuasi mining area in Ghana. Using Hawth's tool an extension in ArcGIS 9.2 software, a total of 48 water sample points in Obuasi and its environs were randomly selected for study. The magnitude of As, Cu, Mn, Fe, Pb, Hg, Zn and Cd in surface water from the sampling sites were measured by flame Atomic Absorption Spectrophotometry (AAS). Water quality parameters including conductivity, pH, total dissolved solids and turbidity were also evaluated. Principal component analysis and cluster analysis, coupled with correlation coefficient analysis, were used to identify possible sources of these heavy metals. Pearson correlation coefficients among total metal concentrations and selected water properties showed a number of strong associations. The results indicate that apart from tap water, surface water in Obuasi has elevated heavy metal concentrations, especially Hg, Pb, As, Cu and Cd, which are above the Ghana Environmental Protection Agency (GEPA) and World Health Organisation (WHO) permissible levels; clearly demonstrating anthropogenic impact. The mean heavy metal concentrations in surface water divided by the corresponding background values of surface water in Obuasi decrease in the order of Cd > Cu > As > Pb > Hg > Zn > Mn > Fe. The results also showed that Cu, Mn, Cd and Fe are largely responsible for the variations in the data, explaining 72% of total variance; while Pb, As and Hg explain only 18.7% of total variance. Three main sources of these heavy metals were identified. As originates from nature (oxidation of sulphide minerals particularly arsenopyrite-FeAsS). Pb derives from water carrying drainage from towns and mine machinery maintenance yards. Cd, Zn, Fe and Mn mainly emanate from industry sources. Hg mainly originates from artisanal small-scale mining. It cannot be said that the difference in concentration of heavy metals might be attributed to difference in proximity to mining-related activities because this is inconsistent with the cluster analysis. Based on cluster analysis SN32, SN42 and SN43 all belong to group one and are spatially similar. But the maximum Cu concentration was found in SN32 while the minimum Cu concentration was found in SN42 and SN43.
Current World Environment Journal, 2014
The concentrations of eight trace elements, Cadmium (Cd), lead (Pb), iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), mercury (Hg) and arsenic(As) in sediment and water were assessed in four artisanal and small-scale mining(ASM) localities in the Amansie West District (6°282 N 1°532 W) of Ghana along two river courses from May 2011 to July 2011. Triplicate water and sediment samples were randomly taken at five different points at each of the localities and the elements determined using Atomic Absorption Spectrophotometer (AAS ). Using the Geoaccumulation Index( I geo ) assessment, the sediments were found to be polluted to different degrees with Cu (Uncontaminated to moderately contaminated/Moderately contaminated), Hg (Uncontaminated to moderately contaminated/Moderately contaminated) and As (Moderately contaminated/Moderately to strongly contaminated). The Enrichment Factor (EF) indicated human influence -artisanal mining activities on the sediment concentration of Cd and Pb for all the localities and only some of the localities for the rest of the trace elements. The elements are major sediment pollutants ( EF > 2) in one or more of the localities. The I geo and EF gave diverse status of the sediment qualities of the localities. Cd, Pb, Hg and As water concentrations in the four artisanal mining localities were all found to be above the WHO maximum acceptable of levels for drinking water. Inhabitants in the mining localities face the risk of getting various diseases by drinking the waters contaminated with the trace elements.
Heavy metals level in streams of Tarkwa gold mining area of Ghana
Heavy metals concentrations in water and sediment samples collected from five streams in Tarkwa gold mining district of Ghana were studied. The water and sediment samples were analysed for As, Al, Cd, Co, Cu, Hg, Mn, Sb, Th, and V, using Instrumental Neutron Activation Analysis (INAA). The results of this study generally showed elevated levels of all the ten examined elements in the water and sediment samples. Angonabeng and Bediabewu rivers recorded high levels of Sb, Mn, Cu, Al, Co, Hg and As in their water samples. The Contamination Factor (CF) results revealed that Teberebie springs are mainly polluted with Sb, Mn V, Al and Cd; and Mile 7 spring sediment is mainly polluted with Sb. Teberebie spring is heavily affected by anthropogenic and natural sources of the ten examined metals according to its Pollution Load Index (PLI). The water-sediment correlation matrix, Pollution Load Index (PLI) and the Contamination degree (Cd) results from this study have revealed that the concentrations of the examined metals in the water column depend on the amount in the sediments, and are directly proportional.
Earth Science Malaysia, 2020
This study assesses environmental receptors impacted by alluvial gold mining at Kibi Goldfields Limited in the Eastern region of Ghana to establish trace metals contamination risk. Specific objectives are to determine concentrations of (1) As, Cr, Ni and Pb in soils, drainage and food crops, using X-ray fluorescence, (2) Cl- in drainage using standard methods. Mean concentrations of As, Cr and Ni in soils are higher at impacted sites than control sites; while Pb and As concentrations in drainage exceeds the maximum contamination guideline values in drinking water. Using Cl- as a conservative tracer, As and Pb are adsorbing from water, while Cr and Ni are desorbing into water. In the food crops, bioaccumulation factors of As and Ni are profound at the impacted site than control sites; Except Cr in cocoyam at impacted sites, translocation factors are negligible in the food crops. Cr bioaccumulates in in cocoyam and plantain at the control site, while Ni bioaccumulates in only plantain...
Trace elements distributions at Datoko- Shega artisanal mining site, northern Ghana
Environmental geochemistry classifies elements into essential, non-essential and toxic elements in relationship to human health. To assess the environmental impact of mining at Datoko-Shega area, the distributions and concentrations of trace elements in stream sediments and soil samples were carried out. X-ray fluorescence analytical technique was used to measure the major and trace element concentrations in sediments and modified fire assay absorption spectrometry in soils. The results showed general depletion of major elements except titanium oxide (TiO2) compared to the average crustal concentrations. The retention of TiO2 at the near surface environment probably was due to the intense tropical weathering accompanied by the removal of fine sediments and soil fractions during the harmattan season by the dry north-east trade winds and sheet wash deposits formed after flash floods. The results also showed extreme contamination of selenium (Se), cadmium (Cd) and mercury (Hg), plus strong contaminations of arsenic (As) and chromium (Cr) in addition to moderate contamination of lead (Pb) in the trace element samples relative to crustal averages in the upper continental crust. However Hg, Pb and Cd concentrations tend to be high around the artisanal workings. It was recognised from the analysis of the results that the artisanal mining activity harnessed and introduces some potentially toxic elements such as Hg, Cd and Pb mostly in the artisan mine sites. But the interpretation of the trace element data thus invalidates the elevation of As concentrations to be from the mine operations. It consequently noticed As values in the mine-impacted areas to be similar or sometimes lower than As values in areas outside the mine sites from the stream sediment results
A pollution assessment survey was performed in the Bonsa River known to be affected by small-scale gold mining(SGM) activities. The environmental and human health risk of arsenic(As), mercury(Hg), manganese(Mn), aluminium(Al) and copper(Cu), as well as the partitioning of these traces within the water/sediment compartments and the influence of basic physic-chemical characteristics-pH, TOC and SO42-content on the traces was evaluated. Arsenic and Hg concentration in riverine water increased by 85% and 660% from the background values of 0.82 µg/L and 0.05µg/L respectively. With exception of Hg and As concentration of Mn and Al were above the WHO guidelines limits for drinking water and freshwater. In the sediment, Hg increased by 1825% from the background concentration of 0.06mg/kg, whereas percent increase in As was insignificant from background value of 1.15mg/Kg. Using sediment quality criteria, contamination factor, geoaccumulation index and enrichment factor values, the river sediment was extensively contaminated with Hg but slightly with Mn. Copper concentration in water/sediment compartment was below the detection limit of 0.01ppb. The ranking order of the mean metal concentration in both matrices followed the conservative order of traces found in the earthcrust except copper. The source of heavy metals was determined from geology and multivariate statistical analysis. The partitioning of As, Hg, Mn and Al in the water/sediment compartments was likely influenced by pH and SO42-. Mercury presented the highest risk to benthic community. Our data emphasis the relevance of environmental and human health concerns associated with extensive and uncontrolled illegal mining activities in Ghana.