Abstract
In this study, the mediating role of 2, 2-Dichlorovinyl Dimethyl Phosphate (diclorvos) in the uptake of metal ions in vegetables is investigated and the health risk assessment conducted toward establishing a health-based approach in vegetable farming for human consumption. The concentrations of Cd and Pb in the vegetables analyzed using Atomic Absorption Spectroscopy (AAS) were observed to be higher in the pesticides treated vegetables compared to the untreated (control). The consumption of the vegetables treated with the pesticides were observed to increase the estimated daily intake (EDI) of the metal ions in humans compared to the EDI level in the untreated groups. The EDI levels were observed to fall in this order Spinach>Sorrel and Pb>Cd. The consumption of the vegetables treated with the pesticides were observed to expose children to a highest EDI of 1.50E-02 mg/kg/day and 2.46E-02 mg/kg/day for Cd and Pb compared to the 1.19E-02 mg/kg/day and 1.55E-02 mg/kg/day in the adults. The susceptibility of the children to non-carcinogenic risk from Cd and Pb exposure through the consumption of the pesticides treated Spinach were observed to be higher. For the metals, a target hazard quotient (THQ) of 1.76E-01 and 8.26E-01 were observed in the treated groups compared to the untreated (1.40E-01 and 5.21E-01). Based on species, the THQ established in the Spinach specie is higher than in Sorrel. All the THQs values recorded in the study are observed to be <1. The health index (HI) for the non-carcinogenic risk were also observed to follow similar trend with the THQ values. Though, the THQ and HI values were observed to be <1 and safe for human consumption, the continual application of the pesticides will increase the concentrations of Cd and Pb and hence, the non-carcinogenic (THQ and HI) risk to a level of concern. Furthermore, the application of pesticides were observed to increase the carcinogenic risk for Cd and Pb exposure through the consumption of the vegetables. The CRI for Cd were higher than the unacceptable range (>10 -4 ). The combine effect (TCRI) further show high carcinogenic risk for children compared to the adults. From the results it will suffice to say that the application of pesticides in vegetable cultivation for human consumption should be regulated or discouraged where possible.
Keywords