Pesticide Residues in Catha Edulis (Muguka): a Multidimensional Threat to Health, Livelihoods, and Environmental Sustainability in Kenya
Year: 2026
Type: article
Abstract: Muguka (Catha edulis), locally recognized as a variety of khat and widely consumed as a stimulant crop in Kenya, is a major source of economic empowerment in Embu County, where it supports approximately 68,500 smallholder farmers and contributes an estimated KSh 20 billion (about USD 154 million) to the national economy annually. Its contribution to the economy aligns with Kenya Vision 2030 and the Bottom-Up Economic Transformation Agenda (BETA), which focuses on sustainable agricultural development. However, the lack of crop-specific pesticide residue regulations on muguka poses significant threats to human health and the sustainability of the sector. While previous studies in Ethiopia have reported pesticide residues in khat leaves, this study provides the first validated evidence from Kenya, focusing specifically on muguka. Pesticide residues were analyzed using Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS) and Gas Chromatography-Mass Spectrometry (GC-MS) techniques, which enabled the detection of multiple compounds across collected samples. A total of 160 samples were collected from four main muguka-growing clusters in Embu County: Embu East (Ena), Embu West (Karorina), Mbeere South (Kiritiri), and Mbeere North (Siakago). The results showed residue levels of concern, with profenofos (an organophosphate insecticide) detected at an average concentration of 237 µg/kg. This exceeded the European Union maximum residue limit (MRL) for leafy vegetables by a factor of five. Deltamethrin (124 µg/kg) and acetamiprid (71.1 µg/kg) were also found. These findings highlight potential health risks for consumers and emphasize the need to develop crop-specific regulatory frameworks. Notably, 86% of applicators reported inadequate use of personal protective equipment (PPE), increasing the risk of chronic exposure. Organophosphates (36%) and carbamates (14%) were the most commonly reported types of synthetic pesticides. These numbers indicate a significant reliance on chemical inputs. As a result, the findings highlight serious shortcomings in both safeguarding public health and promoting sustainable agricultural practices. Unregulated pesticide use in muguka farming poses serious environmental risks, including water pollution, which threatens Kenya’s sustainable development goals. To address these issues, the study recommends comprehensive policy measures, such as establishing muguka-specific maximum residue limits (MRLs), enhancing regulatory enforcement, and providing farmers with targeted training on PPE and safe pesticide use. Additionally, promoting integrated pest management (IPM) can lessen dependence on chemicals, promote eco-friendly practices, and protect farmers and consumers. Key words: muguka, Catha edulis, khat, stimulant crop, pesticide residues, maximum residue limit, GC-MS, LC-MS/MS, Embu County
Authors: RM Njue, C Mburu, P Njogu, C Kathurima, J Mburu
Subfield: Food Science
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $750
OpenAlex ID: W7126088467
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