Determination of the Levels of Some Heavy Metals in Cocoa Beans from Selected Cocoa- Growing Areas in Western and Ashanti Regions of Ghana

摘要

In this study, six heavy metals in cocoa beans from some cocoa-growing towns in the Western and Ashanti regions were determined after acid digestion using analytical grades of concentrated nitric acid and concentrated hydrochloric acid. Cadmium, lead, copper, Manganese, Iron and zinc in the samples were determined by atomic absorption spectroscopy. The metal levels in cocoa beans from the Western region, expressed in mg/ kg varied from 0.045 to 0.066 with mean value of 0.054 for cadmium, from 0.013 to 0.03 with mean value of 0.02 for lead, from 46.47 to 55.17 with mean value of 51.98 for copper, from 48.36 to 64.65 with mean value of 55.18 for manganese, from 43.80 to 53.11 with the mean value of 47.51 iron, from 43.04 to 52.06 with the mean value of 48.29 for zinc. That of Ashanti region ranged from 0.05 to 0.065 with the mean value of 0.056 for cadmium, from 0.014 to 0.02 with the mean value of 0.017 for lead, from 47.43 to 54.17nwith the mean values of 49.10 for copper, from 47.15 to 57.34 with the mean value of 54.62 for manganese, from 50.23 to 63.87 with the mean value of 54.63 for iron and from 53.02 to 58.71 with the mean value of 56.49 for zinc. For overall conclusion, heavy metals were present in all samples but the levels of zinc, copper, iron and manganese which are considered as essential elements were high as compared to the toxic cadmium and lead. Levels according to codex set up by FAO/WHO therefore makes cocoa beans from the Western and Ashanti regions of Ghana analyzed in this study safe for consumption.