Residual levels of organochlorine pesticides in selected locally produced foodstuffs in Gezira scheme, Sudan

Abstract

The aim of this study was to find out the types of organochlorine (OC) pesticides used in the Gezira irrigation scheme of the Sudan as well as the methods of their application and determine the levels of OC pesticide residues in locally produced food items. A questionnaire was administered on 160 farmers randomly selected and 130 samples of locally produced foodstuffs or products, i.e., tomato, okra~ sorghum and cottonseed oil were collected. These foodstuffs were chemically analyzed using Gas Liquid Chromatography (G.L.C.) to determine the levels and types of OC pesticide residues. The findings of this study indicate that a combination of cotton, wheat and sorghum was the most frequent crop-pattern adopted by the farmers. This reflects the importance of cotton as the main cash crop and wheat and sorghum as the main staple foods. Pesticides were used by 97% of the interviewed farmers, but only 24% of them received advice on the proper methods of application. This is because the Sudan cezi r.a Board (S.G.B.) is the main supplier of pesticides, 84% of the respondents quoted it as the source of the pesticides, and the major applicant. Only 18% of the users apply the pesticides by themselves and 12% knew the types of pesticide applied. xiv The major OC pesticide residues detected in the selected samples were Dichlorodiphenyl Trichloroethane (DOT), Hexachloro Hexane (HCH), Hexachloro Benzene (HCB), Aldrin, Dieldrin, Endrin and Heptachlor. All these residues were found in 92% of the samples analyzed. However, the residues were found in samples of tomato, okra, sorghum and cotonseed oil at the rates of 87%, 97%, 87.5% and 100% respectively. This study concludes that the methods of pesticide application used by the farmers compared to the proper methods of application were not correct. When the OC pes~icide residues compared to the maximum residue limits (MRL), only Dieldrin in tomato and Heptachlor in both okra and cottonseed oils were present in levels above the maximum allowed limits by FAO/WHO. The incorrect methods of application and the presence of OC residues is an indication of poor agricultural practices, moreover OCs are banned chemicals in agricultural sector and yet they are still being used.