Estimation of Dermal Exposure to Volatile Organic Compounds (VOCs) from Feminine Hygiene Products: Integrating Measurement Data and Physiologically Based Toxicokinetic (PBTK) Model.

BACKGROUND Increasing studies have informed noteworthy health risks associated with dermal exposure to volatile organic compounds (VOCs) from feminine hygiene products (FHPs). OBJECTIVES This study is to address the gap in understanding the absorption, distribution, metabolism, and excretion dynamics of dermal exposure to VOCs from FHPs, and to identify chemicals and products that could cause significant body burden. METHODS We used measured contents of eight widely present VOCs across five categories of FHPs to estimate dermal exposure, and applied a physiologically based toxicokinetic (PBTK) modeling approach to elucidate VOC toxicokinetics in human body tissues. Inhalation exposure estimates were derived from 20 air samples collected via passive sampling and analyzed using thermal desorption system coupled with gas chromatography-mass spectrometer. Predicted urinary VOC concentrations based on dermal and inhalation exposure were validated against 99 measurements from 25 females. RESULTS Via skin absorption, the estimated levels of most target VOCs in nearly all tissues, except adipose and the rest of the body, rapidly peaked within an hour of product use. Specifically, p-cymene was estimated to reach approximately 2.23 ng/mL in adipose tissue before decreasing over several hours due to efficient excretion pathways, including liver metabolism and exhalation. The model estimated that while the majority of absorbed VOCs (78.9%) were eliminated via liver metabolism, exhalation, and urine excretion, VOCs with logKow higher than 3.5, such as p-cymene, hexane, and n-nonane, exhibited a potential cumulative trend in adipose tissue. This resulted in the estimated VOC concentrations in adipose tissue being 1 to 4 orders of magnitude higher than those estimated in other tissues. Notably, in certain cases, n-nonane posed a potential non-cancer risk (up to 0.07), and benzene presented a notable cancer risk (up to 1.82 × 10-7), primarily attributed to wash and moisturizer, respectively. DISCUSSION These findings reveal potential significant body burden and health risks associated with dermal exposure to VOCs from FHPs, warranting further research and regulatory measures. Comprehensive assessment of internal exposure by integrating with toxicokinetic modeling to elucidate chemical distribution in various tissues is recommended, rather than solely measuring solely one type of biomarkers, to illustrate exposure variances and ensure accurate risk assessment.. https://doi.org/10.1289/EHP15418.