Mancozeb Residue on Tomatoes in Central Uganda.

Emmanuel Kaye,Ruth Muwesa,Innocent Louis Mutambuze,Antony Nyombi

doi:10.5696/i2156-9614-5-8.1

Abstract

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. 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. Tomato samples were analyzed for mancozeb residue determined as carbon disulfide (CS2) by gas chromatography-mass spectrometer (GC-MS). 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. The observed practices at farms are likely to put farmers and final consumers at a risk of exposure to dithiocarbamates.

Highlights

Pesticide residue research supports a number of activities including crop protection, environmental monitoring, consumer protection, and legislative enforcement
These were packaged in new polythene bags that were marked with unique identifier codes and sealed tight to avoid movement that could cause loss of mancozeb surface residues
The sampling was focused on the markets to look at what final consumers take to their homes, and farms to look at the practice and what goes to the markets

Summary

Introduction

Pesticide residue research supports a number of activities including crop protection, environmental monitoring, consumer protection, and legislative enforcement. 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. All the samples analyzed had detectable concentrations of mancozeb residue. The study found that farmers applied 3–6 times the dosage of mancozeb recommended by manufacturers. The observed pre-harvest interval after application of mancozeb was 1–2 days as opposed to 3–7 days set by manufacturers. The observed practices at farms are likely to put farmers and final consumers at a risk of exposure to dithiocarbamates. Dithiocarbamates, Mancozeb, residue, tomatoes, Uganda, fungal disease, fungicide.

Methods

Results

Conclusion