Assessment of Selected Nutrients and Toxic Chemicals in Ethiopian Khat

Abstract

Heavy metal pollution is among the leading health concerns all over the world because of their long-term cumulative effects. khat (Catha edulisforsk), a plant used as a stimulant is grown in certain areas of East Africa and the Arab Peninsula this day it is a known cash crop in Ethiopia. Due to increased demand and value, many farmers have not only begun growing it but have also adopted modern farming methods which include application of fertilizers, pesticides, compost manure, and irrigation. Yet some of these agricultural practices such as application of fertilizers and pesticides are known to increase the concentration of heavy metals such as Cd, Pb, Zn and Cu in the soil. Some of these heavy metals such as Pband Cd are toxic even at low concentrations while Zn, Cu, Fe and Cr though essential in the body, are toxic at high levels This call for monitoring to make sure that the levels of heavy metals in khat do not exceed the threshold limits recommended by WHO due to their adverse health effects to man. This study therefore assesses selected chemical nutrients and toxic metal in khat that is available in Ethiopia. khat samples were collected from16 sits of the three main khat growing regions namely Oromiya, South Nation and Nationality and Amhara regional state Known weights of oven dried khat samples were digested using nitric andPerchloric acids. The digests were analyzed for selected heavy metals using flame atomic absorption spectrophotometer. The following concentration ranges in dry weight (μg/g) were obtained in khat: Zn (25.15-73.95), Cu (0.10-41.80), Cr (ND-39.50), Cd(ND-0.90) and Pb (0.50-13.00). Cd was only detected in khat samples from Oromiyaare more susceptible to adverse effects of Pb than adults. The results suggested that there was significant different (p 0.05) in the levels of heavy metals between khat from various regions. Levels of studied heavy metals in khat were below the maximum limits recommended by WHO except for Pb and Cr Therefore children should be discouraged from chewing khat since they are more susceptible to adverse effects of Pb than adults.