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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/6558

Title: Assessment of copper and zinc in cocoa growing areas in East Akyem Municipality of the Eastern Region of Ghana
Authors: Kani, Alexander Nti
Issue Date: 12-Sep-2013
Abstract: There is an increasing awareness that trace elements and heavy metals present in soil at concentrations above threshold values have negative effects on human health and on the environment. The accumulation of trace elements in the soil is known to restrict the soil’s function, cause toxicity to plants, and contaminate the food chain. This paper reports the concentration of copper and zinc in soils and cocoa beans in the East Akyem Municipality of the Eastern Region of Ghana. Sampling was done in 100 selected cocoa farms. Soil pH, percentage organic matter, copper and zinc were determined at different depth of 0-15 cm and 15-30 cm. The results of the study revealed that the pH of the soil was more acidic at depth 15-30 cm than at depth 0-15 cm and percentage organic matter was also higher at depth 0-15 cm than at depth 15-30 cm.The mean concentration of copper expressed in mg/kg at soil depth 0-15 cm ranged between 0.283±0.179 and 0.526±0.254 and at soil depth 15-30 cm ranged between 0.210±0.093 and 0.415±0.228. The mean concentration of zinc expressed in mg/kg at soil depth 0-15 cm ranged between 4.46±2.18 to 12.61±5.74 and at soil depth 15-30 cm ranged between 2.18±0.86 and 8.44±5.30. Although, the concentration of copper and zinc at depth 0-15 cm was generally higher than at depth 15-30 cmtheir mean differencewas not significantly different (p-value >0.05).The concentration of copper in the cocoa beans recorded values ranging between 0.879 mg/kg and 0.005 mg/kg whilst the concentration of zinc in the cocoa beans also recorded values in the range of 0.15mg/kg to 0.01mg/kg. Concentration of copper in the cocoa beans was always higher than that of zinc across all the sampling sites and their mean difference was statistically significant (p-value<0.05).The concentration of Cu and Zn in the cocoa beans obtained in this study were below the maximum recommended limits set by WHO/FAO and hence pose less or no risk upon consumption, thus, the cocoa beans were not polluted by the Cu nor Zn.The concentration of copper and zinc were higher in the cocoa farm soils than that of the control and their mean difference was significant (p-value<0.05). Soil acidity was found to increase with decreasing organic matter. The mean pH at soil depth 0-15 cm and 15-30 cm differ significantly from percentage organic matter at depth 0-15 cm and at depth 15-30 cm respectively (p-value <0.05).Pollution Index analysis suggests copper and zinc to have serious impacts on the farm soils. There was a strong positive association between the concentrations of Cu and Zn in the cocoa beans and the farm soil. It is expected that the results from this study would be relevant for all trace elements studies in cocoa farms.
Description: A Thesis submitted to the Department of Theoretical and Applied Biology of the Kwame Nkrumah University of Science and Technology, in partial fulfilment of the requirements for the degree of Master of Science (Environmental Science, June-2013
URI: http://hdl.handle.net/123456789/6558
Appears in Collections:College of Science

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