Mancozeb Residue on Tomatoes in Central Uganda

BACKGROUND: Mancozeb belongs to a group of pesticides known as dithiocarbamates (DTC) that are a non-systemic group of pesticides extensively used in Uganda to protect crops from fungal diseases. OBJECTIVES: This study was done in 5 selected districts of Central Uganda with a focus on markets and farms to investigate the current mancozeb concentrations on tomatoes and identify key areas of improvement to minimize human exposure. METHODS: ) by gas chromatography-mass spectrometer (GC-MS). RESULTS: All the samples analyzed had detectable concentrations of mancozeb residue. It was observed that farm samples had mean concentrations of 1.03±0.28 mg/kg, while market samples had 0.77±0.49 mg/kg. The study also found that farmers applied 3-6 times the dosage of mancozeb recommended by manufacturers. Furthermore, the observed pre-harvest interval after application of mancozeb was 1-2 days as opposed to 3-7 days set by manufacturers. CONCLUSIONS: The observed practices at farms are likely to put farmers and final consumers at a risk of exposure to dithiocarbamates.