Determinants of polychlorinated biphenyl levels in plasma from 42-month-old children.

We report on the PCB levels in plasma from 42-month-old children and the factors that determine these levels. We measured the levels of the PCB congeners 118 (2,4,5-3'4' pentachlorobiphenyl (CB)), 138 (2, 3,4-2'4'5'hexaCB), 153 (2,4,5-2'4'5'hexaCB), and 180 (2,3,4, 5-2'4'5'heptaCB) in cord plasma, breast milk, and plasma from 42-month-old children (n = 126) living in the Groningen area, The Netherlands. The sum of the levels of these four congeners was calculated for cord plasma (SigmaPCBcord), breast milk (SigmaPCBmilk), and 42-month plasma (SigmaPCB42mo). SigmaPCBcord was used as a measure of prenatal exposure. Postnatal exposure was assessed in terms of the SigmaPCBmilk and the duration of lactation. In addition, maternal factors including age, body weight and height, parity, and formal education were recorded. In 42-month-old children who have been fully breast-fed for at least six weeks as babies, the median SigmaPCB42mo was 4.5 times as high as that in formula-fed children (0.81 microg/L vs. 0.18 microg/L). The PCB levels in cord blood and human milk and the duration of breast-feeding predict the plasma PCB level at 42 months. Each additional week of full breast-feeding is estimated to result in an increase of 0.3% of the milk PCB level. We concluded that lactation is a major source for the child's PCB body burden at 42 months.