Health risk assessment of pesticides residue in maize and cowpea from Ejura, Ghana.

Low productivity in agriculture due to damage cause by pests has led to the application of pesticides to control pest infestation. Residues of pesticides applied on crops are often found in the food which can cause chronic effect on the health of humans who consume such products. The aim of this study is to measure pesticides residues in maize and cowpea and compare the values with stablished safety limits. A total of 37 pesticides comprising 15 organochlorines, 13 organophosphorus and 9 pyrethroids pesticides were identified in maize and cowpea samples obtained from farms in Ejura. Analytical methods included solvent extraction of the pesticide residues and their subsequent quantification using gas chromatograph equipped with Electron Capture Detector and Pulse Flame Photometric Detector after clean-up on alumina/activated charcoal column. The results showed that the mean concentration of pesticides in maize ranged from 0.001 to 0.103 mg kg(-1) for organochlorine pesticides, 0.002-0.019 mg kg(-1) for organophosphorus pesticides and 0.002-0.028 mg kg(-1) for pyrethroids pesticides. In cowpea the mean concentration ranged from 0.001 to 0.108 mg kg(-1) for organochlorine pesticides, 0.002-0.015 mg kg(-1) for organophosphorus pesticides and 0.001-0.039 mg kg(-1) for pyrethroids pesticides. Maximum Residue Limits for β-HCH, β-endosulfan, p,p'-DDE and p,p'-DDD were exceeded in both maize and cowpea samples. Health risk estimation revealed that residues of heptachlor, dieldrin, endrin, β-endosulfna, γ-chlordane and chlorfenvinphos found in maize exceeded the Acceptable Daily Intake. Similarly the levels of heptachlor and p,p'-DDD found in cowpea also exceeded the Acceptable Daily Intake. This suggests a great potential for chronic toxicity to consumers of these food items.