A review of the health implications of heavy metals and pesticide residues on khat users

Abstract

Background There is an exponential rise in the use of farming chemicals in agricultural practices ostensibly to increase food production. The chewing of fresh khat leaves and shoots has spread across the world from ancient khat producing regions in East Africa and the Arabian Peninsula. Khat is a well-established socialization substance with stimulating characteristics. In this work, we have reviewed the deleterious impacts of several heavy metals such as lead, cadmium, iron in the khat plant and their health impacts. Survey on the health complications of farming chemicals used in khat production is also presented. Main body of the abstract The toxic effects of heavy metals and farming chemicals in plant matter such as khat leaves are a serious health concern. Heavy metals including cadmium (Cd) and lead (Pb), for instance, bio-accumulate in the body and the food chain as precursors for disease. It has been established that blood that has lead levels of 40–60 ug/dL is a precursor for serious health illnesses such as cardiac arrest and cancer. On the other hand, cadmium is reported to bind itself onto metallothioneins hence forming cadmium–metallothionein complex that is transported to all body organs causing deleterious cell damage. The entry of farming chemical into the food chain especially via the chewing of contaminated khat has been known to contribute to health problems such as cancer, hypertension and liver cirrhosis. khat is branded a ‘substance of abuse’ by the World Health Organization (WHO) because of the adverse health risks it causes to humans. Relevant articles published between 2010 and 2021, and archived in PubMed, Google Scholar, Medley, Cochrane, and Web of Science were used in this review. Short conclusion The health implications of heavy metals and farming chemicals arising from the consumption of contaminated khat shoots are a serious concern to the khat chewing community. Consequently, there is need to develop better farming practices that may minimize the absorption of heavy metals and farming chemicals by the khat plant. Information presented in this review is also important in sensitizing policy makers to advance control measures towards safer khat farming practices.

Amassing of heavy metals in soils, vegetables and crop plants irrigated with wastewater: Health risk assessment of heavy metals in Dera Ghazi Khan, Punjab, Pakistan

“…They are very toxic even used in low concentrations, are deadly unsafe for human health, and produce oxidative stress after entry through the food chain either through natural or anthropogenic source. Moreover, heavy metals also cause liver cirrhosis, renal dysfunction, mental retardation, CNS breakdown, cardiovascular disorder, infertility, and degeneration of the basal ganglia of the brain and ultimately cause death ( Sobhanardakani, 2017 ; Oyugi et al., 2021 ; Paithankar et al., 2021 ). For instance, As even at its minute exposure to humans acts as carcinogenic, destroys blood composition, causes anorexia, hair loss, kidney and liver damage, herpes, muscle spasms etc.…”

Khat use and related determinants among pregnant women within Haramaya, Ethiopia: a mixed methods study

“…Several pregnant and lactating women described most chemicals used to treat khat as noxious and causing health-related issues, ranging from gastrointestinal illness to headache to abortion or even death. According to Oyugi and colleagues ( 42 ), smallholder khat farmers have been found to employ various chemicals, including dichlorodiphenyltrichloroethane (DDT), wuhagare (also spelled wuhagar‘ or wuha agar), sevin, malathion, actellic, diazinon and organophosphate pesticides. Unlike other studies, participants in this study described methomyl/90 sp.…”

“…With the ubiquitous use of pesticides and fertilizers to improve food and crop production, exposure to toxic chemicals through various pathways increases the risk to consumer health. Adverse health effects associated with the chemicals used on khat have already been documented ( 42 ), with health diseases ranging from a spectrum of different cancers from DDT, liver damage from heavy metals and pesticides, hypertension, and a deluge of other diseases. Pregnant and lactating women are especially at risk of passing chemicals, such as DDT, through breast milk or affecting the neurodevelopment of a fetus in utero through transplacental transfer ( 45 ).…”

Impact of industrial effluent on selected grass species

“…Excessive metal concentrations in cultivated soils alter the quality of food and have an adverse effect on human health. This raises the danger of kidney and liver failure, infertility and reproductive abnormalities; causes cancer, nervous system breakdown, mental sickness and other toxicity issues (Khan et al 2011;Oyugi et al, 2021). Some heavy metals, such as arsenic, cadmium and certain forms of chromium, are classified as human carcinogens by international health agencies (Balali-Mood et al, 2021).…”