Levels of organochlorine pesticides in the chewable and leftover parts of the khat (Catha edulis) sold in local markets of Jimma Town, Southwest Ethiopia

Abstract

ABSTRACT This study aimed to determine the residual levels of organochlorine pesticides (OCPs) in chewable (tender leaves) and leftovers (mature leaves) of khat sold in local markets in Jimma town, southwest Ethiopia. Samples were collected from various local khat market places in Jimma town, based on their growing origin. A modified QuEChERS method was used to extract pesticides from the samples before their analysis by GC‒MS. The findings indicated that p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) and p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT) were detected in 88.3% and 76.6% of chewable samples, and in 86% and 69% of khat leftovers samples. The p,p’-DDE and p,p’-DDT levels found in chewable khat ranged from 10.12–45.39 and 8.53–34.15 µg/kg, respectively. While in leftover khat they ranged from 30.12–45.04 and 6.73–32.16 µg/kg, respectively. It was found that the concentration of p,p’-DDE is greater than its precursor compound p,p’-DDT for each sample, indicating past use of DDT in the study area. None of the detected analytes exceeded the maximum residue level (MRL) values established by the FAO/WHO or European Commission (EC) of 50 µg/kg. However, no information is available regarding these pesticides’ collective and synergetic negative impacts on consumers.