Transdermal uptake of benzophenone-3 from clothing: comparison of human participant results to model predictions

Sorption of semi-volatile organic compounds to clothing textiles

Clothing can act as a barrier and a source of skin exposure to chemicals due to reversible accumulation on and within textile fibers. The partition coefficient quantifies the equilibrium relationship between textile and air for a specific chemical and is a key parameter in models estimating dermal exposure. Here, textiles composed of natural and/or synthetic fibers were exposed for 26 days in environmental test chambers under different climatic conditions to semi-volatile organic compounds (SVOCs) that have similar, but not identical, physical and chemical properties. The nine textiles tested included a single fiber type or blends of cotton, polyester, nylon, linen and/or elastane. The seven SVOCs are found commonly indoors and in consumer products: 4-t-octylphenol (4t-OP),4-nonylphenol (4-NP); di-n-butyl adipate (DnBA); galaxolide (HHCB); di-n-butyl phthalate (DnBP); benzophenone-3 (BP-3) and 3-(4'-methylbenzylidene)camphor (4-MBC). The chamber air concentrations and masses accumulated on textiles were measured and the mass based (Km, m3/g), area based (Ka, m) and volume based (Kv, dimensionless) partition coefficients were calculated. Partition coefficients among all chemicals were generally lower for polyester and higher for cotton and blends. A hierarchical cluster analysis combined with fiber specific matrix analysis showed that, across the SVOCs tested, the partition coefficients for nylon/elastane were ~ 7 to 70 times higher than for jeans cotton, while the partition coefficient for jeans cotton were ~ 2 to 7 time higher than for polyester. Km, Ka and Kv were lowest for HHCB and highest for 4-NP, DnBP and 4-MBC. However, chemical-textile partition coefficients were not statistically correlated with respect to physical and environmental properties of the SVOCs. The values were statistically the same for different chamber air concentrations of the chemicals tested, and from 24 °C to 33 °C there was only a weak reduction in the partition coefficients.

Relationship between the use of hair products and urine benzophenone-3: the Korean National Environmental Health Survey (KoNEHS) cycle 4

Background

Benzophenone-3 is a type of ketone with 2 benzene rings attached to a carbonyl group (C=O) and one benzene ring attached to a hydroxyl group (-OH). As an endocrine-disrupting chemical, benzophenone-3 is known to be associated with reproductive, developmental, thyroid, and endocrine toxicities. Benzophenone-3 is commonly used in hair products, cosmetics, and ultraviolet (UV) filters because of its characteristic property to absorb UV light. This study aims to investigate the association between the use of hair products and urine benzophenone-3 using the data from the Korean National Environmental Health Survey (KoNEHS) cycle 4 (2018-2020), which represents the Korean population.

Methods

Using the KoNEHS cycle 4 survey, the data of 3,796 adults aged ≥ 19 years were analyzed. Based on the 75th percentile concentration of urine benzophenone-3, the participants were divided into the low- and high-concentration groups. Chi-square test was conducted to analyze the association of urine benzophenone-3 with distribution of general characteristics, use of personal care products, consumption of marine foods, and use of plastic products as the variable. Logistic regression analysis was conducted to calculate odds ratios (ORs) for the high-concentration group of urine benzophenone-3 based on the use of hair products.

Results

Women with < 6 times or ≥ 6 times of hair product usage had significantly higher adjusted ORs compared to those who did not use hair products. The calculated ORs were 1.24 (95% confidence interval [CI]: 1.12-1.38) for women with < 6 times of usage and 1.54 (95% CI: 1.33-1.79) for women with ≥ 6 times of usage.

Conclusions

This study revealed the association between the use of hair products and the concentration of urine benzophenone-3 in the general Korean population.

Reducing Transdermal Uptake of Semivolatile Plasticizers from Indoor Environments: A Clothing Intervention

Models and laboratory studies suggest that everyday clothing influences the transdermal uptake of semivolatile organic compounds, including phthalate plasticizers, from indoor environments. However, this effect has not been documented in environmental exposure settings. In this pilot study, we quantified daily excretion of 17 urinary metabolites (μg/day) for phthalates and phthalate alternatives in nine participants during 5 days. On Day 0, baseline daily excretion was determined in participants' urine. Starting on Day 1, participants refrained from eating phthalate-heavy foods and using personal care products. On Days 3 and 4, participants wore precleaned clothing as an exposure intervention. We observed a reduction in the daily excretion of phthalates during the intervention; mono-n-butyl phthalate, monoisobutyl phthalate (MiBP), and monobenzyl phthalate were significantly reduced by 35, 38, and 56%, respectively. Summed metabolites of di(2-ethylhexyl)phthalate (DEHP) were also reduced (27%; not statistically significant). A similar reduction among phthalate alternatives was not observed. The daily excretion of MiBP during the nonintervention period strongly correlated with indoor air concentrations of diisobutyl phthalate (DiBP), suggesting that inhalation and transdermal uptake of DiBP from the air in homes are dominant exposure pathways. The results indicate that precleaned clothing can significantly reduce environmental exposure to phthalates and phthalate alternatives.

Exposure to oxybenzone from sunscreens: daily transdermal uptake estimation

BACKGROUND

Fugacity, the driving force for transdermal uptake of chemicals, can be difficult to predict based only on the composition of complex, non-ideal mixtures such as personal care products.

OBJECTIVE

Compare the predicted transdermal uptake of benzophenone-3 (BP-3) from sunscreen lotions, based on direct measurements of BP-3 fugacity in those products, to results of human subject experiments.

METHODS

We measured fugacity relative to pure BP-3, for commercial sunscreens and laboratory mixtures, using a previously developed/solid-phase microextraction (SPME) method. The measured fugacity was combined with a transdermal uptake model to simulate urinary excretion rates of BP-3 resulting from sunscreen use. The model simulations were based on the reported conditions of four previously published human subject studies, accounting for area applied, time applied, showering and other factors.

RESULTS

The fugacities of commercial lotions containing 3-6% w/w BP-3 were ~20% of the supercooled liquid vapor pressure. Simulated dermal uptake, based on these fugacities, are within a factor of 3 of the mean results reported from two human-subject studies. However, the model significantly underpredicts total excreted mass from two other human-subject studies. This discrepancy may be due to limitations in model inputs, such as fugacity of BP-3 in lotions used in those studies.

SIGNIFICANCE

The results suggest that combining measured fugacity with such a model may provide order-of-magnitude accurate predictions of transdermal uptake of BP-3 from daily application of sunscreen products.

Photoprotection by clothing: A review

Clothing is recognized by leading health agencies as a primary method to protect against the harmful effects of photodamage caused by ultraviolet (UV) radiation and visible light. The photoprotective capacity of clothing is commonly measured as the ultraviolet protective factor (UPF). While the technology driving photoprotective clothing has been well-established, there continues to be efforts to discover new materials to improve the UPF of clothing. Here, we show increased Google searches for photoprotective clothing over the last decade, suggesting a high level of public interest in photoprotective clothing. In addition, we investigate the frequency of UPF-graded photoprotective clothing sold by large retail stores featured in Fortune 1000. We review factors that alter the UPF of clothing and describe emerging textile technologies used to increase clothing's photoprotective capacity. Finally, we compare how photoprotective clothing is regulated among different countries, the importance of photoprotective clothing in occupational health, and research in visible light and clothing photoprotection.