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Metal Contamination of an Underground Gold Picking Zone in the Department of Djekanou, Cote D’Ivoire
Ouattara Bakary,
Aka Ané Maurice,
Yao Kouakou Alphonse,
Seka Yapoga Jean,
Gnagne Essoh Yves,
Yapo Ossey Bernard
Issue:
Volume 9, Issue 1, February 2021
Pages:
1-10
Received:
5 December 2020
Accepted:
14 December 2020
Published:
22 January 2021
Abstract: Illegal gold mining has developed in recent years in the department of Djékanou with the rising cost of gold on the world market, due to the slump in local agricultural products and the unemployment of young people of working age. It has become an essential activity along with agriculture and farming in rural areas. It is an effective way to fight poverty. However, this practice is likely to cause significant environmental damage. Thus, to assess the environmental quality of this region prone to gold mining activity, the determination of the level of metallic contamination of environmental matrices (soils and sediments) was carried out. Four (4) soil and sediment sampling campaigns took place in dry and rainy seasons on the illegal gold mining site and near the dam, all located at about 685 m from Yobouékro, on the gold washing site of Taffissou at 3,425 m from Djékanou and at Groudji in the department of Djékanou. The sediment sampling was carried out by Strahler's method, while that of the soils was taken at random over the extent of the gold washing sites. The total concentrations of metals in the different matrices were determined by atomic absorption spectrophotometry (AAS). The analytical results show that the metal contents are lower than the natural content of each element in the earth's crust (UCC). Gold mining activities are not currently a source of metallic contamination of the environment. Also, the contamination factors recorded from the concentrations of metals are all less than 1, indicating low contamination of sediments and soils by trace metal elements despite intense gold mining activity. Notwithstanding, the evaluation of the environmental quality from the concentrations of the metals Cd, Co, Cr, Hg and Pb compared to the American guide values SQGs (TEC and PEC), it is noted that the receiving environment is contaminated only by mercury, cadmium and cyanide; the values of the other parameters studied being lower than the guide values. The two matrices mentioned above were also assayed with cyanide and the results revealed that the sites of Groudji and Taffissou are contaminated.
Abstract: Illegal gold mining has developed in recent years in the department of Djékanou with the rising cost of gold on the world market, due to the slump in local agricultural products and the unemployment of young people of working age. It has become an essential activity along with agriculture and farming in rural areas. It is an effective way to fight ...
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Forest Cover Dynamics Detection in Lume District, Oromia Region, Central Ethiopia
Issue:
Volume 9, Issue 1, February 2021
Pages:
11-20
Received:
12 October 2020
Accepted:
2 November 2020
Published:
10 March 2021
Abstract: Forest cover dynamics is a critical global problem that affects the socio-economic and ecological function of forest landscape in the globe The Earth's forest cover is continuously altered by several climatological and anthropogenic factors. And its change influence world carbon cycle and biodiversity pool at local, regional and global scale. Lume district in Ethiopia is one of potential area that has important socio-economic and ecological function. Currently, despite their contribution to both economic and ecological services forests of Lume district are under serious streak both from anthropogenic and natural calamities. Hence, the fundamental aim of this study is to investigate the magnitude, trend and rate of forest cover change for the last 33 years (1985-2018). Quantitative data was collected using Landsat5 TM and Landsat8 OLI_TIRS satellite image, which used to define the spatial and temporal changes. SCP, QGIS 2.18.2, MOLUSCE and EXCEL were used for processing and analyzing data obtained from satellite image (https://earthexplorer.usgs.gov/). Four period Landsat image data of 1985, 1999, 2013 and 2018 were used to produce land cover map in general and forest cover map in particular. The finding of the study depicted that, during 33 years period agriculture land and urban building increased by 728ha (10.82%), 1547.92ha (21.39%) respectively with equivalent decline of 3887ha (5.37%) forestland and 17502.55ha (24.2%) shrub land. Throughout the study periods, steady net increasing rate of expansions observed for urban buildings and agriculture land by 468.8ha and 237.27ha/annual, whereas, a net decline rate noted for scrublands and forests by 530.38ha and 117.8ha/year. The main findings of this study disclosed that, a resume increase in agriculture land and urban buildings and settlements at the expense of forests and shrub lands throughout investigated periods. Hence, in order to revoke the problem of forest cover change and its impact, proper measures had been forwarded which can be implemented both in the long and short-term commitment of anxious stakeholders in the district and national level.
Abstract: Forest cover dynamics is a critical global problem that affects the socio-economic and ecological function of forest landscape in the globe The Earth's forest cover is continuously altered by several climatological and anthropogenic factors. And its change influence world carbon cycle and biodiversity pool at local, regional and global scale. Lume ...
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Shear Strength and Consolidation Characteristics of Lateritic Soils: A Case of Asela Town, Oromia Regional State, Ethiopia
Issue:
Volume 9, Issue 1, February 2021
Pages:
21-28
Received:
30 November 2020
Accepted:
10 December 2020
Published:
17 March 2021
Abstract: The most important engineering properties that determine the bearing capacity of soils are shear strength or ability to resist sliding along internal surfaces within a soil mass and the consolidation characteristics. Thus, in this study the shear strength and consolidation characteristics of Asela lateritic soil is studied. The shear strength parameters (i.e. Cohesion (C) and internal friction angle (Ф)) and consolidation parameters are determined using UU triaxial and 1-D odometer tests, respectively, on disturbed soil samples remolded with different densities and water contents in order to simulate the field condition. The shear strength test was done on the cylindrical samples of 38mm in diameter and a height of twice the diameter and the consolidation test were done on the samples of 75mm diameter and thickness of 20mm. In addition, the index test (specific gravity, grain size distribution, Atterberg limits and free swell tests) also conducted on air and oven-dried samples to understand the behavior and classification of the soils. The moisture content of the studied soil ranges between 17.35 – 32.51%, plasticity Index ranges between 11.8-26.4%, clay fraction ranges between 25.5-61.2, free swell ranges between 20-50% and specific gravity ranges between 2.59-2.95. The shear strength parameter, C and ɸ range from 89.63 to 161.48 Kpa and 17º-24º, respectively. The consolidation parameters: coefficient of compression ranges 0.193 to 0.581; coefficient of consolidation ranges 0.11 to 1.06 cm2/sec, coefficient of volume compressibility ranges 0.021 to 0.34m2/MN.
Abstract: The most important engineering properties that determine the bearing capacity of soils are shear strength or ability to resist sliding along internal surfaces within a soil mass and the consolidation characteristics. Thus, in this study the shear strength and consolidation characteristics of Asela lateritic soil is studied. The shear strength param...
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