Human Health Risk Evaluation of Organophosphate Insecticide Residues in Post-Harvest Cowpea in Gwagwalada, Abuja, Nigeria.

Background: Cowpea is a leguminous crop commonly grown and eaten in Nigeria. Organophosphate insecticides are frequently used to control insect populations in cowpea crops.

Objectives: The present study was conducted to investigate the concentrations of organophosphate insecticide residues in cowpea varieties in Gwagwalada, Nigeria, and assess health risks to consumers.

Methods: Samples of brown and white cowpea varieties were collected from Gwagwalada market, Abuja, Nigeria. Concentrations of organophosphate insecticide residues in the cowpea samples were analyzed by gas chromatography-mass spectrometry with selective ion monitoring. Risk evaluation was carried out by the determination of estimated daily intake, hazard quotient and chronic hazard index.

Results: The organophosphates detected in the cowpea varieties were malathion, parathion, ethion and carbophenothion. The concentrations of insecticides in the cowpea types were higher than the maximum residue limits recommended by the European Union (EU) and the Agency for Toxic Substances and Disease Registry (ATSDR). The hazard quotient values were less than 100% for malathion, parathion and ethion in the cowpea varieties for adults and children. The hazard quotient of carbophenothion for adults was below 100% for the cowpea types, while the hazard quotient surpassed 100% for children. The chronic hazard indexes for children were 364% and 276% for the brown and white cowpea types, respectively.

Conclusions: The results obtained in the present study indicate that consumers, particularly children, may be exposed to health risks through the consumption of cowpea types. Consequently, monitoring and regulation of organophosphate insecticide usage in Nigeria should be intensified.