Pesticide Residues Detected in Selected Crops, Fish and Soil from Irrigation Sites in the Upper East Region of Ghana

Crops, soil and fish from irrigation farms were investigated in the Upper East Region of Ghana. Questionnaire was administered to collect pesticide use information from farmers, and tomatoes, okro, pepper and garden eggs as well as fish and soil samples were collected and analysed using Gas Chromatography-Electron Capture Detector (GC-ECD). The results were compared with standard acceptable Maximum Residue Limits (MRLs). The results indicated that up to 35.9% of 50 respondent farmers frequently cultivated tomatoes. 50% of the farmers have been using agrochemicals for the past 5 years, with glyphosphate as the most commonly used (42%). 65 % of the farmers indicated that information on proper use or handling of agrochemicals was obtained from colleague farmers. High levels of organochlorine residues (2.232-5.112 ng/g) were found in okro and garden eggs from the Tono site, and also pepper and tomatoes from Pungu site. 6 pesticides residues were found in 5 varieties of tomatoes samples analysed with Lindane and Aldrin having the highest concentration of 0.00069 and 0.027 μg/g respectively. 4 soil samples contained detectable levels of β-HCH and α-Endosulfan (organochlorines), while all 6 samples had one or more traces of 10 organophosphate pesticides. Chlorpyrifos was widely available and in quite high levels. 21 organochlorine residues were detected in tilapia and mud fishes, 17 in fishes from the Precast yard water. Residual concentration of Aldrin and Cis-heptachlor (1069.7 ng/g and 780.7 ng/g respectively) in tilapia from the Tono dam was noted to be above the acceptable limits.