DECREASE IN MILK AND BLOOD DIOXIN LEVELS OVER 2 YEARS IN A MOTHER NURSING TWINS - ESTIMATES OF DECREASED MATERNAL AND INCREASED INFANT DIOXIN BODY BURDEN FROM NURSING

This study addresses the issue of breast-feeding and its reduction of maternal dioxin body burden. Nursing is also a source of infant dioxin exposure. This study extends our previous efforts to investigate a nu rsing mother's milk and blood dioxin levels. We report polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) dioxi n toxic equivalents (TEQs) in milk (M) and blood (B) both before and a lso after two years of nursing twins to be 16.9 ppt (M), 14.9 ppt (B), and 3.1 ppt (M) and 4.9 ppt (B), respectively. The ratios of measured congeners comparing milk to whole blood from a nursing mother taken i nitially and after two years of nursing vary from 0.36 to 8.40 in 1992 and 0.17 to 1.0 in 1994. The mother's body burden was initially calcu lated to be 329 ng TEQ from milk levels and 291 ng TEQ from blood leve ls using samples taken in February 1992 and decreased to 60.1 ng TEQ f rom milk and 96 ng TEQ from measured blood using samples collected in December 1994. We calculate that the excretion of dioxin TEQ by the mo ther through breastfeeding is 269 ng TEQ, which is similar to the 303 ng TEQ estimated total dioxin intake by the twins over two years. The average daily dioxin intake from nursing is 66 pg TEQ/kg-BW/day for ea ch twin over the two years.