PYRETHROID AND DDT RESIDUES IN HUMAN BREAST MILK FROM KWAZULU-NATAL, SOUTH AFRICA

Abstract

ISEE-433 Introduction: In both developing and developed countries, human breast milk remains the best sole nutrient source for infants (especially in the early stages of infancy), even though it could contain pollutants, such as PCBs and DDT. The presence of DDT and other organochlorine compounds in human breast milk has been known for quite some time, from malaria and non-malaria areas. The restriction on or banning of many of these compounds for agriculture in most parts of the world has led to gradual reductions in the levels of organochlorine compounds in breast milk, especially in developed countries. For malaria control however, DDT is still being used in South Africa, although it was interrupted for five years, when pyrethroids were used. Pyrethroids are also being used in significant amounts in agriculture. Aim: We investigated the presence of pyrethroids and DDT in breast milk of women from the northern part of KwaZulu-Natal, that experienced both active malaria control by DDT, and for five years by deltamethrin, and increased agricultural use of insecticides, some of which are pyrethroids. Methods: A total of 152 samples were analysed using GC for the various isomers of DDT, as well as permethrin, cyfluthrin, cypermethrin and deltamethrin. Results: The mothers from Jozini (an active malaria control area) had significantly higher levels of DDT (∑DDT 4.48 mg/kg milk fat) than women from Gwaliweni (∑DDT 1.1 mg/kg milk fat), which served as the reference site. There were, however, no differences between total pyrethroid levels at the two sites (0.647 and 0.211 mg/kg milk fat respectively), and permethrin, rather than deltamethrin made up most of the pyrethroid residues. Multiparae mothers also seemed to have higher pyrethroid levels than primiparae, although this was not significant. Although the Jozini DDT levels were lower than a previous survey done 14 years ago from a comparable town close by (Mseleni, ∑DDT 15.8 mg/kg milk fat), this reduction can be ascribed to the five-year interval with no DDT application, before DDT application was resumed one year before sampling. There is little evidence however, of the deltamethrin applied for malaria control, still being present in breast milk, as only 41% of mothers from Jozini had detectable residues. Conclusion: The pyrethroids that were found are probably derived from agricultural use. This does mean, however, that with pyrethroids being applied, either for malaria control or for agriculture, active ingredients can be transferred to infants' via breast milk, and that the risks posed by the simultaneous presence of DDT and pyrethroids in breast milk should be further investigated.