posted on 2022-04-05, 21:05authored byDaniel Dawson, Hunter Fisher, Abigail E. Noble, Qingyu Meng, Anne Cooper Doherty, Yuko Sakano, Daniel Vallero, Rogelio Tornero-Velez, Elaine A. Cohen Hubal
1,4-Dioxane is a persistent and mobile
organic chemical that has
been found by the United States Environmental Protection Agency (USEPA)
to be an unreasonable risk to human health in some occupational contexts.
1,4-Dioxane is released into the environment as industrial waste and
occurs in some personal-care products as an unintended byproduct.
However, limited exposure assessments have been conducted outside
of an occupational context. In this study, the USEPA simulation modeling
tool, Stochastic Human Exposure and Dose Simulator-High Throughput
(SHEDS-HT), was adapted to estimate the exposure and chemical mass
released down the drain (DTD) from drinking water consumption and
product use. 1,4-Dioxane concentrations measured in drinking water
and consumer products were used by SHEDS-HT to evaluate and compare
the contributions of these sources to exposure and mass released DTD.
Modeling results showed that compared to people whose daily per capita
exposure came from only products (2.29 × 10–7 to 2.92 × 10–7 mg/kg/day), people exposed
to both contaminated water and product use had higher per capita median
exposures (1.90 × 10–6 to 4.27 × 10–6 mg/kg/day), with exposure mass primarily attributable
to water consumption (75–91%). Last, we demonstrate through
simulation that while a potential regulatory action could broadly
reduce DTD release, the proportional reduction in exposure would be
most significant for people with no or low water contamination.