Concentrations and health risk assessment of organophosphorus pesticides residues in common cereal samples from Ngalda agricultural area, Yobe State, Northeastern Nigeria

Abstract

Organophosphorus pesticides (OPPs) are a well-known class of man-made chemicals frequently used to protect crops against pests giving rise to accumulation of these chemicals in foods. In the present study, the residual levels and potential health risk associated with four (4) organophosphorus pesticides (diazinon, dichlorvos, chlorpyrifos and fenitrothion) in cereals (maize, millet, wheat and rice) samples collected from Ngalda agricultural area, Fika Local Government Area, Yobe State were analyzed. Extractions and clean-up of the samples were carried out using standard procedures. The levels of the OPPs in cereals samples were determined using GC-MS coupled with flame photometric detector. The analysis of OPPs residues in maize, millet, wheat and rice revealed that the residual levels of the studied OPPs were highest in maize samples ranging from 3.97E-01 – 6.83E-01 mg/kg. On the contrary, rice samples had the least concentrations range of 1.09E-02 - 1.06E-01 mg/kg. The detected OPPs in all the maize, millet and wheat samples exceeded corresponding maximum residue limits (MRLs). However, the levels in rice samples were all lower than the recommended MRLs. The hazard index (HI) through consumption of maize for adults (1.60E+01 - 2.23E+03) and children (2.87E+01 - 3.99E+03); millet for adults (1.11E+01 - 5.96E+02) and children (1.99E+01 - 1.07E+03); wheat for adults (7.72E+00 - 1.71E+03) and children (1.39E+01 - 4.20E+01); and rice for adults (1.46E+00 - 3.61E+02) and children (2.62E+00 - 6.47E+02). HI values were all > 1, suggesting that consumption of these cereals by both age groups from the study area might pose danger of potential health risk. Furthermore, higher risk indices were recorded for children through crop consumption than adults.