Determination of Organophosphorus Pesticide Residues in Olives Grown in Bursa, Turkey

The use of pesticides in agriculture has been continuously increasing in recent years and has led to an increase in world food production. Organophosphorus compounds are among the most widely used pesticides in the world. Because of their long half-life time, they contaminate soils as well as surface and ground water. In addition, these residues in food constitute a significant health risk. Olive and its products are extensively consumed foods in the Mediterranean countries. However, olive trees are attacked by several pests and diseases, making it necessary to apply pesticides to ensure crop protection, which can leave residues on the fruit. Because pesticide residues in food constitute a significant health risk and olive oil has a high consumption rate among people of the producing countries, the continuous control of pesticide residues in olive oil is of great importance. In this study, the occurrence of nine organophosphorus pesticide residues in olives (Olea europaea L. 'Gemlik') in Mudanya and Gemlik towns (Bursa, Turkey; latitude: 29 degrees 04'E, longitude: 40 degrees 39'N) was investigated. Olive samples in the black maturation stage from twenty orchards were analyzed for pesticide residues using different extraction methods by capillary gas chromatography (GC) using NPD with a capillary column. Of the eight organophosphorus pesticides investigated, four were detected in olives namely azinphosethyl, chlorpyrifos, chlorpyrifos-methyl, and carbophenothion. The other four, diazinon, methidathion, malathion, and pirimiphos-methyl, were below detection limits. All samples contained more than one pesticide and 17 were found to contain chlorpyrifos at concentrations slightly above the maximum pesticide residue limit (100 mu g kg(-1), MRL).