Agricultural and Biological Research

Organochlorine pesticide residues level in khat and possible human health risks to chewers in Wondogenet district, Sidama regional state, Ethiopia

Sisay Shediso Roriso*, Solomon Sorsa Sota, Girma Tilahun Yimer and Yohannes Seifu Berego

To prevent khat plant from destruction of pests and increase its productivity, farmers use different types of pesticides. In Ethiopia, khat is chewed by millions everyday mainly by youngsters. Since it is chewed by many, it is believed that a significant residue level of pesticides to be found in chewable parts of khat which result in adverse effect among the chewing population. The aim of the present study was assessing the organochlorine pesticide residues concentration of on chewable parts of khat and its possible human health risks on chewers. Thirty edible parts of khat samples were collected from both non irrigated and irrigated farms in Wondogenet district. Extraction and cleanup process of pesticide residue of khat samples were undertaken following Quick, Easy, Cheap, Effective, Rugged and Safe extraction (QuEChERS) method. Concentrations of pesticide residue were determined using Gas Chromatography-Mass Spectrometry (GCMS)/ Mass Spectrometry (MS) and non-carcinogenic health risk assessments and carcinogenic risk assessments were estimated. Among the 20 targeted Organochlorine Pesticides (OCPs) for analysis in khat samples from non-irrigated farms in this study, 14 residues were detected. The concentrations of the detected OCPs ranged from 0.021 μg/kg to 25.69 μg/kg. Among the analyzed OCPs in khat samples from irrigated farms, 15 residues were detected. Concentration of detected OCPs ranged 0.055 μg/kg to 53.392 μg/kg. Two pesticides in khat have been found to exceed the default European Commission (EC) maximum limit. These pesticides were endrin aldehyde and methoxychlor. With the mean residue of endrin aldehyde in khat was 25.69 μg kg^-1, which was twice that of European Union Maximum Residue Limit (EU-MRL) (10 μg kg^-1). The mean concentration of methoxychlor in khat was 10.608, which was higher than that of EU-MRL (10 μg kg^-1). The Target Hazard Quotient (THQ) for endrin aldehyde was greater than 1 which shows the non-carcinogenic health risk associated with endrin aldehyde among chewers of khat. The Carcinogenic Hazard Index (CHI) values obtained from chewing khat at irrigated farms were less than 1 but at non-irrigated sites were greater than one (CHI>1) for high consumption probability. This result shows that the chewing of khat from non-irrigated sites at high end consumption probability poses significant non-carcinogenic health hazards. The Potential Carcinogenic Risk (PCR) and Hazard Ratio (HR) values obtained in the present study were less than one for OCPs in both non-irrigated and irrigated farms. This indicates that chewing of khat from both non-irrigated and irrigated farms have no carcinogenic risk to human health. Therefore, it is imperative to monitor pesticide level in khat and policy makers are advised to take an appropriate action at this alarming level to safeguard people from the treat of pesticide pollution from irrigated and non-irrigated areas.