Abstract

Pesticides constitute the major source of potential environmental hazard to man and animal, as they are present and concentrated in the food chain. Paraquat (1,1¹-dimethyl-4,4¹-bipyridylium dichloride) is one of the most highly toxic herbicide to be marketed over the last 60 years. Although, Paraquat (PQ) has been banned or severely restricted in most countries, its use continues in some, especially in Nigeria. Therefore, this study investigated possible occurrence of PQ in some commonly consumed vegetables, crops and fruits in Abeokuta using spectrophotometric method. This study was conducted on 150 samples of different kinds of crops, vegetables and fruits (harvested from Fadama farmland of the University of Agriculture, Abeokuta) to assess the presence and levels of PQ residues. PQ residues was found to present at 0.13±0.02, 0.27±0.02, 0.06±0.01, 0.10±0.03, 0.15±0.03, 0.09±0.02, 0.09±0.02, 0.04±0.01 and 0.05±0.01 ppm in  Talinum triangulare,  Corchorus olitorius, Amaranthus caudatus, Cratylia argentea, Capsicum frutescens, Lycopersicum esculentum, Raphanusativus,  Zea may and Dioscorea alata, respectively. Paraquat residues were not detectable inM. paradisicica and C. papaya using this method. The method achieves mean recovery of over 80% and is repeatable with overall coefficient of variation of 8.0% (n=10) at 0.05-1.0 ppm fortification level. All residue levels detected were within the PQ tolerance or maximum pesticide limits.

Key words: Occurrence, Paraquat residues, Nigerian, crops, vegetables, fruits.