Estimation of lactating mothers' daily intakes of bisphenol A using breast milk

Breast milk is a unique biological sample that reflects the exposure levels of both lactating mothers and infants. The exposure levels of BPA due to breast milk consumption for infants can be estimated easily, but the method to estimate the total daily intake (TDI) of lactating mothers from breast milk has not yet been established. In this study, BPA concentrations were detected in breast milk samples from 149 lactating mothers from Hunan, China. The median concentration of BPA in breast milk was 0.053 mu g/L with a range of 0.001-2.535 mu g/L, and a temporal decline trend was found for BPA concentrations in breast milk (p < 0.05). The median intake of BPA via breast milk was 26.8 ng/kg bw/day for 0-3-month-old infants and 7.0 ng/kg bw/day for 4-12-month-old infants. Based on the predicted concentrations of BPA in urine and blood via the conversion coefficients from breast milk, the TDIs of lactating mothers were estimated. The TDIs estimated from the simulated urine concentration were 84.0 +/- 175.2 ng/kg bw/day for 0-3-month-old infants' mothers and 36.9 +/- 80.8 ng/kg bw/day for 4-12-month old infants' mothers. The dietary daily intakes estimated from the simulated blood concentration were 579.6 +/- 370.8 ng/kg bw/day for 0-3-month-old infants' mothers and 280.1 +/- 195.2 ng/kg bw/day for 4-12-month-old infants' mothers. When assuming the dietary daily intakes in Hunan of the fifth total diet study (TDS) as the true total dietary intake of our population, the contribution of diet was estimated to be 63.7%, which suggested that non-dietary BPA exposure may be underestimated.

Automated summary

This study in Hunan, China found BPA concentrations in breast milk samples from 149 lactating mothers, with different TDIs for infants and lactating mothers. The study revealed a temporal decline trend in BPA concentrations in breast milk.