Leonard Mwetich Muruny¹, Kiplagat Ayabei^1,, Samuel Lutta¹, Stephen Barasa¹

Tomatoes are one of the most cultivated and consumed vegetables worldwide. The use of pesticides for crop protection is important; however, their presence in the food web is of great concern to human health. This study aimed to assess the level of pesticide residues in tomatoes sold in common markets of Uasin Gishu County. A total of 300 samples of fresh tomatoes were collected from six sub-counties of Uasin Gishu County. The samples were analyzed to quantify two pesticides using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) multi- residue extraction, followed by High Performance Liquid Chromatography (HPLC). Health risk assessment was conducted using Target Hazard Quotient (THQ) and Hazard Index (HI) calculations for the population. Lambda-cyhalothrin concentrations ranged from 0.0297 to 0.8502 mg/kg. Approximately 73% of samples exceeded the European Union MRL (0.07 mg/kg), and 60% surpassed the Codex MRL (0.3 mg/kg). The highest concentration of lambda-cyhalothrin was observed in Cheptiret market (0.8502 ± 0.0146 mg/kg). Mancozeb residues were also detected at levels below both the EU (3.0 mg/kg) and Codex (2.0 mg/kg) MRLs. Health risk assessment revealed THQ and HI values below 1.0 for all markets. The highest combined HI for children was 0.088 at Cheptiret market, indicating 8.8% of the threshold for potential adverse health effects. This study demonstrates non-compliance with international pesticide MRLs for lambda-cyhalothrin in tomatoes from Uasin Gishu County markets, highlighting significant gaps in pre-harvest interval adherence and pesticide application practices. While acute health risks appear low based on current exposure models, long-term exposure warrants monitoring, particularly for vulnerable populations. The findings emphasize the need for strengthened continuous residue monitoring and consumer awareness programs to ensure food safety and protect public health in Kenya's horticultural sector.

Tomatoes, Public Health, Lambda-cyhalothrin, Mancozeb, pesticide residues, QuEChERS, HPLC, Maximum Residue Limits, health risk assessment, food safety