Level of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls (PCDD/Fs, PCBs) in human milk and the input to infant body burden

This study determined PCDD/F and PCB levels in human milk, examined factors associated with levels of contamination, and assessed the infant body burden from breast-feeding. The congeners of PCDD/Fs, dioxin-like PCBs, and indicator PCBs were analyzed by HRGC/HRMS for 36 human milk samples from healthy women, aged 20–35 years, from December 2000 to November 2001 in central Taiwan. Mean levels of WHO-TEQs in human milk were 10.5 (95% CI=8.8–12.2) and 14.5 (95% CI=12.5–16.5) pg-TEQ/g lipid for those <29 and ≧29 years old, respectively. PCB 138 concentration significantly predicted total WHO-TEQs with r2=0.84 (p<0.001). Milk level of dioxin-TEQ was 9.63 pg-TEQ/g lipid (95% CI=7.0–13.2) in those with a yearly income $29,000 compared to 6.3 pg-TEQ/g lipid (95% CI=5.2–7.6) for those whose yearly income was $18,000 per year. Women who reported being Buddhist (64.3 ng/g lipid) had significantly higher indicator PCB concentrations than did those who reported being Taoist (35.3 ng/g lipid). The monthly dioxin intake of exclusively breastfed infants decreased with increasing duration of lactation. The cumulative dose of exclusively breastfed infants (76.5 ng TEQ, 95% CI=69.7–83.3) was significantly greater compared to that of formula-fed infants (CI=16.4–17.0) at one year and to that of infants at birth (3.90 ng TEQ, 95% CI=3.6–4.2). Our findings suggest that breast-feeding should be strongly encouraged for infants in Taiwan.