Organochlorine pesticide residues in chicken fat andeggs
Kahunyo, J K
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The issue of pesticide residues arising from pesticide use in controlling pests of agricultural, veterinary and domestic importance may be considered a recent world wide concern. Especially notorious are the organochlorine insecticides which are persistent and highly lipid soluble leaving residues in various forms of life as well as the atmosphere, soil and water. Presence of residues in food intended for human consumption is undesirable as these chemicals are poisonous and long-term exposure co"uld pose a health hazard to man. Realising the potential dangers of pesticide residues and with the intention of protecting consumers, most developed countries have set up national food monitoring laboratories which carry out frequent checks on the residue levels in both agricultural and animal products. They have also set national tolerances for pesticides in different commodities. Despite the fact that organochlorine insecticides have been used over the years for various purposes in Kenya, there is little published information regarding the pesticide residue situation in the country, and also a general lack of co-ordinated research aimed at realising this vital goal. National tolerances for organochlorines in milk have been set by the Kenya Bureau of Standards but for most other commodities, the·Bureau has to rely on the FAO/WHO Codex Alimentarius Commission's guidelines. The aim of this study was to establish if organochlorine pesticide residues occur in poultry products, in Kenya and if they do, what their nature and levels are. As part of the study, the risk to consumers of such products was to be assessed by comparing detected levels to Practical Residue Limit (PRL) levels set by the Codex Alimentarius Commission. One hundred and five chicken fat samples and aft equal number of egg samples were collected from seven different areas around Central Kenya and formed the main part of the study. A subsidiary lot of forty egg samp Le s were taken from the Coast Province. Samples were taken from farmers on commercial as well as small scale poultry establishments in the selected areas. The samples were processed using multiresidue analytical methods which included both liquid-liquid partitioning and column chromatographic clean up procedures. Pesticides were then determined by a Packard Model 128 Gas Chromatograph with an Electron Capture detector employing a 63 Ni radioactive source and Nitrogen as the carrier gas. Confirmation of suspected residues was done by gas liquid chromatography on the same instrument but employing a different column. A total of twelve organochlorine compounds were detected from the two types of samples, the number of compounds detected varying from one sample to the other. Ten of the twelve compounds were allocated to four groups, the~e being Lindane, Dieldrin (comprises aldrin and dieldrin), Heptachlor (comprises heptachlor and heptachlor epoxide), and the DDT group (pp-DDT, pp-DDE, pp-DDD, op-DDT and op-DDD) . rr_ and S-BHC were the other two compounds detected. Of the one hundred and five chicken fat samples examined, 99 samples (94%) were positive for lindane, 1 among these having a-level above the Codex Alimentarius Commission's practical residue limit for lindane in chicken fat; 16 samples (15%) were positive for heptachlor; 65 (62%) were positive for dieldrin; while 101 (96%) were positive for DDT, 2 (2%) among which had levels above the PRL for DDT. Of the one hundred and five egg samples in the main part of the study, 15 samples (14%) were positive for lindane with none in which residue levels exceeded the practical residue limit for lindane in eggs, none of the 105 samples were positive for heptachlor; 40 samples (38%) were positive for dieldrin; and 90 (86%) were positive for DDT with 18 (17%) among these having levels above the PRL for DDT in eggs. Of the fourty egg samples from the Coast Province, seven (17.5%) were positive for lindane; none were positive for either heptachlor or dieldrin; while 33 samples (82.5%) were positive for DDT, 6 (15%) among which had DDT residue levels exceeding the PRL .• The highest incidence among the two types of samples was for the DDT group followed by lindane, dieldrin and lastly heptachlor. The results of the study show that only in the case of DDT (total) in eggs did the mean residue concentration exceed the practical residue limit. Notwithstanding the few individual values of other compounds which exceeded the PRL values, the general indication is that except for DDT in eggs, a serious pesticide residue problem does not exist in the two poultry products examined.