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

Tomato samples were analyzed for mancozeb residue determined as carbon disulfide (CS2) 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.