Abstract:
Khat (Catha edulis) is one of the most consumed plant in the horn of African countries. However, it is a
stimulant plant that has several side effects on the health of consumers. On top of that, the khat leaves
used for human consumption are often contain contaminants such as pesticide residues. The present
study aims to investigate the level of DDT residue and its metabolites (p'p-DDE, p'p-DDD, o'p-DDT and
p'p-DDT) in khat samples and to undertake exposure assessment to consumers. The khat samples were
collected from local markets in southwestern Ethiopia. Consumption survey was undertaken using 24 h
recall method for both male and female khat consumers. The finding showed that 80% of the khat
samples contained DDT and its metabolites. Some of the residues were above the maximum residue limit
(MRL) set by Food and Agricultural Organization (FAO). The concentration of p'p-DDE and p'p-DDT in
khat were in the range of 0.033e0.113 and 0.010e0.026 mg/kg, respectively. High concentration of the
metabolite (p'p-DDE) compared to the parent compound (p'p-DDT) revealed the historical use of DDT in
the study area. Probabilistic exposure analysis indicated that the mean and 97.5 percentile (P97.5), of the
estimated daily intake of total DDT were 0.002 and 0.006 mg/kg bw/day, respectively. The study
concluded that khat consumers are exposed to the stimulant effect of the plant as well as DDT and its
metabolites in Jimma zone.
