Pesticide Action Network Updates Service (PANUPS)
Despite bans in many countries, DDT is still used in some parts of the world. For example, DDT continues to be used in Mexico, although it has been limited to malaria control since 1972. In the past year, several studies have been published that examine levels of DDT, its metabolites and other organochlorines in human breast milk.
Researchers tested levels of DDT metabolites in the breast milk of fifty mothers living in Mexico City in 1994 and 1995. The study found that 6% of their babies had daily DDT intakes greater than the acceptable level set by the World Health Organization and the Food and Agriculture Organization (.005 mg/kg). The maximum concentration of DDT found in this study indicated that some children received over 13 times the acceptable daily intake. The study included medium- and low-income women who had lived in Mexico City for at least a year before giving birth. Factors that affected levels of DDT and its metabolites in the participants' breast milk included age, place of residence, consumption of salted meat and fish, and total amount of time breastfeeding.
Seventy-five percent of breast milk is derived from body fat, with only 25% derived from the mother's current diet. A study of women in Veracruz, Mexico, compared levels of organochlorine pesticides in mothers' fat tissue and breast milk. Samples were collected from sixty women in 1997 and 1998. All were found to contain DDT metabolites or other pesticide metabolites as well as the organochlorine pesticides hexachlorobenzene (HCB) and ß-hexachlorocyclohexane (ß-HCH).
In the Ukraine, researchers tested breast milk of mothers living in the cities of Kiev and Dniprodzerzhinsk for organochlorine pesticides, their metabolites and PCBs. Samples of breast milk as well as placenta and cord from 197 women who had given birth in 1993 and 1994 were tested for organochlorine pesticides and their metabolites. The chemicals found in the highest concentrations were ß-HCH and a DDT metabolite. Levels of ß-HCH were high compared with those found in similar studies conducted in Europe. Levels of DDT and its metabolite DDE were higher than many, though not all, levels found in European studies.
In another study, researchers compiled and standardized data from 130 previous studies in order to review global trends in average levels of DDT in breast milk. The data show a downward trend in DDT concentrations in breast milk since about 1970. For the U.S. and Canada, the data suggest an 11% to 21% per year reduction in average levels of DDT in breast milk since 1975. Data for Western Europe show approximately a 9% to 13% reduction per year. Difficulties in analyzing the data include the fact that age, total time breast-feeding, and other relevant characteristics in study participants could not be standardized across studies, and the fact that bans on DDT were phased in only gradually in some countries. Overall, the study results suggest that placing bans on persistent pollutants such as DDT can produce significant and measurable reductions in body stores after several years.
Sources: Beth C. Gladen et al., "Organochlorines in Breast Milk from Two Cities in Ukraine." Environmental Health Perspectives 107(6), June 1999, pp. 459-462. Daniel Smith, "Worldwide Trends in DDT Levels in Human Breast Milk." International Journal of Epidemiology 28(2), April 1999, pp. 179-188. Laura Torres-Arreola et al., "Levels of Dichloro-Dyphenyl-Trichloroethane (DDT) Metabolites in Maternal Milk and Their Determinant Factors," Archives of Environmental Health 54(2), March/April 1999, p. 124-129. S. M. Waliszewski et al., "Comparison of Organochlorine Pesticide Levels in Adipose Tissue and Human Milk of Mothers Living in Veracruz, Mexico," Bulletin of Environmental Contamination and Toxicology 62(6), June 1999, pp. 685-690.