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Search Results: 1 - 10 of 304224 matches for " D.K. Dodoo "
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ANALYSIS OF VEHICULAR FALLOUTS FROM TRAFFIC IN THE KUMASI METROPOLIS, GHANA
D.K. Essumang*, D.K. Dodoo, S. Obiri, B.A.K. Oduro
Bulletin of the Chemical Society of Ethiopia , 2006,
Abstract: Concentrations of platinum, lead, cadmium, copper, and zinc in dust from areas of high, medium, low and very low vehicular movements in Kumasi Metropolis in the Ashanti Region of the Republic of Ghana was measured. High concentrations of platinum, lead, copper, and zinc were found to be associated with soils from areas of high traffic densities suggesting that vehicles (that ply these areas) also contribute heavy metals to the environment. The results of the study shows that the road and users, like residents living in buildings within these areas, those engaged in commercial activities like hawking, and the general public are at risk of exposure to the toxic effects of Pt, Pb, Cd, Cu, and Zn as they inhale those metals released from the exhaust of vehicles into the environment. According to these results, there is the potential for exposure to high levels of Pt, Cd, Pb, Cu, and Zn for road users and those living in urban environments or along the highways. KEY WORDS: Catalytic converter, Vehicular fallouts, Toxic metals, High, Medium, Low and Very low traffic conditions, Kumasi Metropolis (Ghana). Bull. Chem. Soc. Ethiop. 2006, 20(1), 9-15.
Lindane and propuxur residues in the top soils of some cocoa growing areas in five districts of the Central Region of Ghana
J.K. Bentum, D.K. Essumang, D.K. Dodoo
Bulletin of the Chemical Society of Ethiopia , 2006,
Abstract: Lindane and propoxur residues in some topsoil samples from five cocoa growing districts in the Central Region of Ghana have been determined. Ten soil samples were taken randomly at a depth of 0-10 cm from pre-selected farms in each district. Some physical and chemical properties of the soils were determined. The pesticide residues were extracted from 50 g of topsoil by continuous Soxhlet extraction using a (1:1 v/v) acetone-chloroform mixture for six hours. Clean up of the extract was done by liquid-liquid partitioning and column chromatography using alumina and silica gel adsorbents. The pesticide residues were finally analysed by gas- chromatography using 63Ni electron capture detector (ECD) and flame ionization detector (FID) for lindane and propoxur, respectively. Lindane and propoxur pesticide residues were found to be present in all the soils to which these pesticides had already been applied. Generally, lindane residues occurred in greater amounts than propoxur. The concentrations of lindane ranged from 2.1 to 15.4 mg kg-1 and propoxur from 1.71 to 7.95 mg kg-1. Both the extracted lindane and propoxur residues correlated negatively with pH, cation exchange capacity, moisture content, and organic carbon. Propoxur correlated positively with the amount of clay but there was no significant correlation between the amount of clay and the extracted lindane concentration. KEY WORDS: Lindane, Propoxur, Soil, Pesticide monitoring Bull. Chem. Soc. Ethiop. 2006, 20(2), 193-199.
Analysis of vehicular fallouts from traffic in the Kumasi Metropolis, Ghana
D.K. Essumang,D.K. Dodoo,S. Obiri,B.A.K. Oduro
Bulletin of the Chemical Society of Ethiopia , 2006,
Abstract: Concentrations of platinum, lead, cadmium, copper, and zinc in dust from areas of high, medium, low and very low vehicular movements in Kumasi Metropolis in the Ashanti Region of the Republic of Ghana was measured. High concentrations of platinum, lead, copper, and zinc were found to be associated with soils from areas of high traffic densities suggesting that vehicles (that ply these areas) also contribute heavy metals to the environment. The results of the study shows that the road and users, like residents living in buildings within these areas, those engaged in commercial activities like hawking, and the general public are at risk of exposure to the toxic effects of Pt, Pb, Cd, Cu, and Zn as they inhale those metals released from the exhaust of vehicles into the environment. According to these results, there is the potential for exposure to high levels of Pt, Cd, Pb, Cu, and Zn for road users and those living in urban environments or along the highways.
DETERMINATION OF FREE CYANIDE AND TOTAL CYANIDE CONCENTRATIONS IN SURFACE AND UNDERGROUND WATERS IN BOGOSO AND ITS SURROUNDING AREAS IN GHANA
S. Obiri, D.K. Dodoo, F. Okai-Sam, D.K. Essumang
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: Concentrations of free cyanide and total cyanide in water samples in Bogoso and its surrounding areas in Ghana have been measured in this study. Concentrations of free cyanide and total cyanide were found to be above the maximum permissible discharge limit of effluent from mining companies into natural waters set by Environmental Protection Agency, Ghana (GEPA). A comparison of the results obtained in this study with permissible levels set by US Environmental Protection Agency and the World Health Organization reveals that surface waters in the study areas are highly polluted with cyanide and it's not safe for human consumptions. This means that, the resident in and around Bogoso are at risk. KEY WORDS: Free cyanide, Total cyanide, River Bogo, River Aprepre (River Dumasi), River Ankobra Bull. Chem. Soc. Ethiop. 2007, 21(2), 213-220.
Determination of free cyanide and total cyanide concentrations in surface and underground waters in Bogoso and its surrounding areas in Ghana
S. Obiri,D.K. Dodoo,F. Okai-Sam,D.K. Essumang
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: Concentrations of free cyanide and total cyanide in water samples in Bogoso and its surrounding areas in Ghana have been measured in this study. Concentrations of free cyanide and total cyanide were found to be above the maximum permissible discharge limit of effluent from mining companies into natural waters set by Environmental Protection Agency, Ghana (GEPA). A comparison of the results obtained in this study with permissible levels set by US Environmental Protection Agency and the World Health Organization reveals that surface waters in the study areas are highly polluted with cyanide and it's not safe for human consumptions. This means that, the resident in and around Bogoso are at risk.
SOME CHEMICAL CHARACTERISTICS OF THE RIVER PRA ESTUARY IN THE WESTERN REGION OF GHANA
J.K. Tufuor, D.K. Dodoo, A.K. Armah, G.A. Darpaah, D.K. Essumang
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: This paper discusses the nutrients budget and transfers of mineral nutrients from land to the sea that influence significantly the biogeochemical process operating in the coastal ecosystem. Water samples were collected fortnightly from six sites in the estuary and analysed using standard methods of analyses. It was observed that the estuary is alkaline in nature and the alkalinity increases, in the lower reach of the river as it flowed into the sea. The estuary could be classified as a well-mixed estuary due to the vertical homogenous distribution of salinity. The inorganic nitrogen in the water body exists predominately in the form of nitrate (NO3-), as compared to concentrations of ammonium (NH4+) and nitrite (NO2-). The ranges of NO3-, NH4+ and NO2- concentrations are (4.98-8.27), (0.11-0.46) and (0.005-10.95) x 10-3 mg/L. The concentrations of nitrate, nitrite, ammonium and phosphate were found to be within WHO specification. The calculated residual flow (VR) for both November and December are -2.7 x 107 m3 day-1and -1.01 x 107 m3 day-1, respectively. The negative value of VR implies that water flows from the system. The corresponding residence and flush times are 324 and 109 seconds and 828 and 595.2 seconds for November and December, respectively. Bull. Chem. Soc. Ethiop. 2007, 21(3), 341-348.
Assessment of Levels of Cadmium and Mercury of Two Estuaries in Two Regions of Ghana
A. Sam,D.K. Dodoo,D.K. Essumang,C.K. Adokoh,G. Doe Nutifafa,Y. Ameyaw
Research Journal of Applied Sciences , 2012, DOI: 10.3923/rjasci.2010.40.46
Abstract: Instrumental Neutron Analysis by Americium-Beryllium radioisotope neutron source was employed for the determination of mercury and cadmium from eight different sites of the Pra and Ayensu estuaries in Ghana. Mercury and cadmium were identified in μg g-1 levels and values correlated with the pH values of water column and soil samples. Substrates like the Blue Tilapia and the European Green Crab were used as bioaccumulation indicators for the mercury levels in the various samples. A summary of the mean, minimum and maximum soil/water mercury and cadmium concentrations detected for the 8 sites with the widest geographical distribution; river bank at Beposo showed a maximum of 3.95x10 3 μg g-1 of mercury which is far below the Environmental Protection Agency s permissible limit of 0.134 μg g-1. Insignificantly low levels of mercury concentrations were analyzed in shoulder soils and water samples over the period of the study. A significantly high levels of concentrations of mercury existed in the riverbed sediments as compared to that for the riverbank sediments, water and the shoulder soils. The degree of concentrations of mercury showed that mercury and cadmium concentrations decreased significantly and gradually as one moved from Beposo to the Shama beach through Bosomdo and Krobo. Mercury and Cadmium residues were also recorded in both European green Crab and blue tilapia. The levels of the two elements were slightly high in the Crab as compared to the Blue Tilapia. The differences could be attributed to the fact that the Crab is a bottom-dweller and predator. The concentrations of the two elements were far below the world permissible levels.
Some chemical characteristics of the River Pra Estuary in the Western region of Ghana
J.K. Tufuor,D.K. Dodoo,A.K. Armah,G.A. Darpaah
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: This paper discusses the nutrients budget and transfers of mineral nutrients from land to the sea that influence significantly the biogeochemical process operating in the coastal ecosystem. Water samples were collected fortnightly from six sites in the estuary and analysed using standard methods of analyses. It was observed that the estuary is alkaline in nature and the alkalinity increases, in the lower reach of the river as it flowed into the sea. The estuary could be classified as a well-mixed estuary due to the vertical homogenous distribution of salinity. The inorganic nitrogen in the water body exists predominately in the form of nitrate (NO3-), as compared to concentrations of ammonium (NH4+) and nitrite (NO2-). The ranges of NO3-, NH4+ and NO2- concentrations are (4.98-8.27), (0.11-0.46) and (0.005-10.95) x 10-3 mg/L. The concentrations of nitrate, nitrite, ammonium and phosphate were found to be within WHO specification. The calculated residual flow (VR) for both November and December are -2.7 x 107 m3 day-1 and -1.01 x 107 m3 day-1, respectively. The negative value of VR implies that water flows from the system. The corresponding residence and flush times are 324 and 109 seconds and 828 and 595.2 seconds for November and December, respectively.
Avalia??o de diferentes coberturas na supress?o de plantas daninhas no cerrado
Meschede, D.K.;
Planta Daninha , 2007, DOI: 10.1590/S0100-83582007000300005
Abstract: the definition of plant species with higher production for soil mulching is one of the main factors for a successful no-tillage system. the practice of soil tillage in tropical and subtropical regions based on intensive soil revolving results in decreased organic matter and increased weed incidence. thus, the aim of this work was to compare the potential of different soil mulching to suppress weeds under no-tillage system in brazilian cerrado areas. thus, seven treatments were evaluated consisting of the following soil crop covers: millet adr 500 (penisetum americanum l.), millet adr300, sorghum (sorghum bicolor l.), maize (zea mays l.), crotalaria (crotalaria juncea l.), castorbean plant (ricinus communis l.) and spontaneous vegetation. a randomized block experimental design with 4 replications was used. sorghum yielded the highest dry matter weight (11.890 kg ha-1); sorghum, millet and crotalaria showed a better ability to suppress weeds. the spontaneous vegetation presented the lowest biomass values. maize and castorbean presented a lower crop cover potential. biomass accumulation by the covers was inversely proportional to weed biomass.
Seed conditioning of red oak: a recalcitrant North American seed
Struve, D.K.;
Scientia Agricola , 1998, DOI: 10.1590/S0103-90161998000500012
Abstract: a ten day aerated water soak was developed as a seed conditioning treatment for red oak (quercus rubra l.). conditioned seeds had higher germination completeness, uniformity and speed compared to control seeds. seeds could be conditioned under a wide range of temperatures and durations. conditioned seeds were maintained at 70c for 30 days without loss of seed quality. during conditioning, pericarps split in response to seed hydration. split pericarps could be used as a pre-sowing indicator for high quality seeds. seed conditioning was ineffective on dormant seeds. increased crop uniformity and higher stand establishment can be realized by subjecting red oak acorns to an aerated water soak treatment followed by selecting seeds with split pericarps. these results are especially important in container production systems where limited numbers of value seeds are available.
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