Assessment of copper residue in cocoa pods and beans in cocoa growing areas in the central region of Ghana

Abstract

Copper concentrations in cocoa pods and beans in samples of cocoa collected between February and March 2000 from eleven cocoa growing towns in the central Region of Ghana were determined. In all a total of three hundred samples were taken randomly from preselected farms. Copper fungicides were applied in ten of the farms and the eleventh farm where there was no application of copper fungicide served as a control. Analysis for copper was done using atomic absorption spectrometer. The concentration of copper in the pods ranged from 0.02 to 0.39mg kg-1 with an average of 0.22mg kg-1 while the range in the beans was 0.01 to 0.22mg kg -1 with an average of 0.13mg kg -1. The pod thickness ranged from 0.60 to 1.20cm with an average of 0.90cm. The ratio of copper levels in the cocoa pods to the levels in the beans ranged from 1.33 to 2.67. Averagely, the concentration of the copper in cocoa fruit indicated a higher accumulation of the element in the pods than in the beans with 62% of the total copper concentration in the cocoa fruit contained in the pod while 38% was observed in the beans. A positive significant (P<0.05) correlation existed between concentration of copper in the beans and cocoa pods. Similarly, a positive significant correlation existed between the beans copper concentration and pods thickness as well as pods copper concentration and pod thickness (P<0.05)