Polybrominated diphenyl ethers exposure in breast milk in Shanghai, China: levels, influencing factors and potential health risk for infants.

The use of polybrominated diphenyl ethers (PBDEs) is increasing annually in China. Although several studies have reported significant contamination by these compounds in biological samples in China, little is known about the factors that may influence the levels of exposure and the potential health risk for infants. We investigated PBDE exposure levels in breast milk, its influencing factors and the potential health risk for infants in Shanghai, China by enrolling 48 healthy women between September 2006 and April 2007. PBDE exposure was assessed by analyses of seven PBDE congeners in breast milk. The estimated daily intake of PBDEs by infants via breastfeeding was determined for evaluating the potential health risk for infants. The median (range) of total PBDE content in breast milk was 8.81 (1.92-41.55) ng/g lipid. 34 (71%) of the 48 samples tested positive for all seven congeners. Maternal education level and household monthly salary were positively associated with PBDE concentration in breast milk (r=0.337, p=0.019 and r=0.436, p=0.004, respectively). The median of estimated daily intake of BDE-99 (6.67 ng/kg/day) by infants via breastfeeding was below the human no adverse effect level (NAEL) set for BDE-99 for neurodevelopmental toxicity (18.8 ng/kg/day). However, 3 (6%) of the samples exceeded the human NAEL. Taking the high detection rate of PBDEs in breast milk together with 6% of their EDI higher than NAEL in Shanghai, more studies on the effects of maternal PBDE exposure on fetal growth and child neurodevelopment are warranted.