Original Articles: 2013 Vol: 5 Issue: 6
A survey of copper, lead, cadmium and zinc residues in cocoa beans obtained from selected plantations in Nigeria
Black pod disease is the most prevalent disease of Theobroma cacao L. The most popular means of controlling the disease among cocoa farmers in Nigeria is the use of copper-based fungicides. Due to the possibility of fraction of applied fungicide being retained in the beans as residue, the European Union set maximum residue limits for all pesticides used on cocoa during production. Since a considerable proportion of Nigerian cocoa beans is marketed in Europe, it became necessary to assess the levels of some heavy metals in cocoa beans obtained from selected plantations within three cocoa producing States in Nigeria. Ripe cocoa pods were collected from the farmers’ field and processed according to standard procedures. Portion of the processed samples were digested and analyzed for Cu, Pb, Cd and Zn using Buck Scientific Atomic Absorption Spectrophotometer. Result show that, copper residues in all the samples were below maximum residue limits while cadmium was not detected in most of the samples except in few samples from Ondo State. The few samples that have detectable cadmium were below the maximum residue limit for cadmium. However, the level of Pb in most of the samples obtained from Cross River and Ondo States were moderately high. This may be due to inherent Pb content of the soils on which the crop is grown.