Biomonitoring of parabens in human milk and placenta and estimated daily intake in northern Taiwan.

backgroundParabens are endocrine-disrupting chemicals that are widely used as preservatives in the form of methyl (MP)-, ethyl-, propyl-, and butyl-paraben in cosmetics, personal care products, food, and pharmaceuticals.

objectiveThis study analyzed the presence of four parabens in 268 human milk samples and 189 placental samples collected from pregnant women in Taiwan and calculated the estimated daily intake (EDI) of total parabens among breastfed infants at one and three months of age.

methodsParabens were analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry. We also explored the dietary and PCP factors associated with parabens exposure. Monte Carlo simulation was employed to characterize uncertainty in the EDI calculation.

resultsOur findings indicate that MP was the most frequently detected paraben in placental, first- and third-month milk, with detection frequencies of 57%, 80%, and 45%, respectively. The Σparabens concentration ranged from below the limit of detection (LOD) to 8.2 ng/g in placenta, < LOD to 35.8 ng/g in first-month milk, and < LOD to 21.6 ng/g in third-month milk. Furthermore, the 95th percentile EDI of MP was higher in third-month milk (617 ng/kg-day) compared to first-month milk (118 ng/kg-day), yet remained several orders of magnitude below the EFSA-established acceptable daily intake of 10 mg/kg-day. SIGNIFICANCE: This biomonitoring study highlights the widespread, low-level exposure of infants to parabens, especially MP, through both prenatal and postnatal pathways. These findings reinforce the need for continued surveillance of parabens exposure during the critical developmental period. IMPACT: This study is among the first large-scale biomonitoring studies to measure parabens in placenta and human milk samples from an Asian population. Methylparaben emerged as the most commonly detected parabens in both placenta and breast milk, indicating both prenatal and postnatal exposure for infants. Although the estimated daily intake levels were well below the safety thresholds, the detection of parabens in the early developmental period raises concern for potential long-term health effects. By integrating biomonitoring data with maternal dietary habits and personal care product use, this work highlights the need for continuous monitoring and regulatory measures of early-life parabens exposure.