Evaluating the use of silicone wristbands and urinary biomarkers to assess personal exposure to phthalates

BACKGROUND: Biomonitoring studies for phthalates often rely on concentrations of urinary biomarkers, but there is interest in broadening exposure assessment methods, especially for use with vulnerable populations like pregnant women. Silicone wristbands (wristbands) are non-invasive passive sampling devices that have been shown as valid exposure assessment tools for a variety of chemicals and could provide a complementary method of phthalate exposure assessment. OBJECTIVE: This study examined the relationship between phthalates detected in wristbands and their corresponding urinary metabolites to understand the ability of wristbands to capture phthalates. METHODS: This pilot study included 27 pregnant women from the New York City-based longitudinal birth cohort study, the Fair Start Cohort. One wristband and spot urine samples provided at three time points were collected during a single 48-hour period. Six phthalate levels in wristbands were compared with the corresponding 12 urinary metabolite concentrations. Linear regressions and k-means clustering were employed to describe the relationship between, and information generated from wristband and urine matrices. RESULTS: Three of the six parent phthalates were significantly positively associated with at least one of their metabolites in urine (butylbenzyl phthalate with monobenzyl phthalate; di-2-ethylhexyl phthalate with mono-2-ethylhexyl phthalate; di-iso-butyl phthalate with mono-hydroxy-isobutyl phthalate, mono-isobutyl phthalate, and the molar sum of these metabolites). Exposure marker profiles differed between wristband and urine matrices, which may reflect differences in routes of exposures. IMPACT: This study demonstrates the ability of wristbands to capture personal exposure to phthalates and their substitutes. Additionally, using wristbands as an exposure assessment method could fill the gap in our understanding of the contribution of inhalation and dermal exposure routes for phthalate exposure, as these remain understudied in the literature.