Abstract

Indiscriminate use of pesticides to boost agricultural produce and in public health to control pests has raised the emphasis on pesticide residue levels in foods. This study analyzed the pesticides residue levels in some common food crops consumed in Nigeria, and ascertained their suitability for human consumption. The samples were analyzed for the presence of 15 organochlorine and 10 carbamate pesticide residues using gas chromatography-mass spectrometry (GC-MS). The residual pesticides levels and hazard index in the different food crops were compared with WHO established maximum residual levels (MRL) for the pesticides. The results showed no detectable levels of pesticides in the yam samples. Beans samples, contained hexachlorobenzene and its median level (0.025 mg/kg) was greater than the MRL (0.01 mg/kg). A total of 14 (56%) different pesticides were detected in each of red and green apples, 10 (40%) in pepper and 3 (12%) in rice. The most occurring pesticides in the crops were propachlor, endosulfan-1 and hexachlorobenzene. The median pesticides contents in pepper were greater than their respective MRLs. Organochlorine pesticides are still being used in cultivation of crops, or in storage of food crops and also in some imported plant foods. Crop contents of pesticides found were below the estimated life time exposure (mg/kg/day) of 65 kg man as well as the hazard index of 1. This may pose no immediate risks to human health, but long term effects should be considered.

Key word: Pesticide residues, food crops, maximum residual limit (MRL), harzard index (HI), gas chromatography-mass spectrometry (GC-MS).