摘要：Pesticide residue analysis carried out at the farm gate, market level and other spatial scales may be of immense significance as an indicator of the potential risks that pesticide exposure has on human health. Cabbage samples at the farm-gate were analysed to determine the types of pesticides used by vegetable farmers in Cape Coast and ascertain whether levels of pesticide residues are below permissible Maximum Residue Limits. Twenty-one pesticide residues were detected in the cabbage samples of which 9 are pyrethroids and 12 are organophosphates . Pesticide residues at levels exceeding the Maximum Residue Limits were found in more than two-thirds of the total number of samples. The results are as follows: Allethrin (1.52411±3.024054 mg kg-1), deltamethrin (4.74690±1.694768 mg kg-1), cypermethrin (0.31180±0.367967 mg kg-1), fenvalerate 2 (0.20590±0.150179 mg kg-1), permethrin (0.14700±0.066119 mg kg-1), ethoprophos (1.13544±0.442078 μg g-1), phorate (0.67820±0.809661 μg g-1), chlorfenvinp (0.31520±0.155821 μg g-1) and fenitrothion (0.16500±0.189241 μg g-1). High levels of pesticide residue were observed for allenthrin (9.566 mg kg-1) and phorate (2.077 μg g-1). Three of the pesticide residues (cypermethrin, permethrin and parathion) are considered to be potentially carcinogenic. Methamidophos and fenvalerate are the only pesticide residues that were not detected in any of the samples whereas fonofos, profenofos, clorfenvinp and pirimiphos-methyl were restricted to cabbage samples from only one location. Strong correlations exist among a number of pesticide residues suggesting a common origin. Principal component analysis indicates that the data is a two-component system explaining 63% of total variance. Component 1 shows strong positive factor loadings on cypermethrin, deltamethrin and cyfluthrin 3 whereas component 2 shows strong negative factor loadings on phorate and fenvalerate 2. Cluster analysis grouped the pesticide residues into two spatially dissimilar categories of 6 and 4 members. The high levels and wide assortment of pesticide residues found in this study suggest the need to put into effect regulations regarding the proper use of pesticides on vegetables.
