Determinants of Xenoestrogen Exposure and Implications on Inter- and Intra-Variation of Urinary Biomarkers across Individuals
Exposure to xenoestrogens such as parabens, bisphenols, triclosan and triclocarban is ubiquitous given their widespread use in consumer products. Spot urine samples provide a snapshot of chemical exposure concentrations at one point in time. The extent of variation exhibited by an individual in relation to the overall variability observed across a population is unclear. The objective of this study was to evaluate the exposure of healthy adults living in Western Massachusetts to a panel of xenoestrogens and investigate inter- and intra-individual variability as well as potential predictors of exposure. In this study we present results from an intensive biomonitoring campaign where morning (09:00) and evening (17:00) urine samples were collected from 10 participants over a 5-day period. Samples were prepared for analysis by liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) using solid phase extraction. Concentrations of eight environmental xenoestrogens, including parabens (methyl-, ethyl-, propyl-, butyl-), bisphenol-A (BPA), bisphenol-S (BPS), triclosan and triclocarban were measured in urine in their unconjugated and conjugated forms. Hourly inventories of consumer and personal care product use, thermal paper handling as well as water and food consumption were also collected from participants. The association between these potential exposure factors and concentrations of xenoestrogens measured in urine were evaluated. Our optimized solid phase extraction procedure and MS/MS parameters achieved good sensitivity and recoveries ranging from 85 to 105%. Variability of creatinine adjusted paraben, BPA, BPS, triclosan and triclocarban concentrations in urine measured within and between individuals will be presented. Potential exposure sources will further be discussed.