Prolonged Exposure to Bisphenol A from Single Dermal Contact Events

Abstract

Bisphenol A (BPA) is an endocrine disruptor frequently detected in human biofluids. Dermal absorption of BPA from thermal paper receipts occurs but BPA pharmacokinetics following dermal exposure is not understood. To compare the pharmacokinetics of dermal and dietary BPA exposure, six male participants handled simulated receipts containing relevant levels of BPA (isotope-labeled BPA-d) for 5 min, followed by hand-washing 2 h later. Urine (0-48 h) and serum (0-7.5 h) were monitored for free and total BPA-d. One week later, participants returned for a dietary administration with monitoring as above. One participant repeated the dermal administration with extended monitoring of urine (9 days) and serum (2 days). After dietary exposure, urine total BPA-d peaked within 5 h and quickly cleared within 24 h. After dermal exposure, cumulative excretion increased linearly for 2 days, and half the participants still had detectable urinary total BPA-d after 1 week. The participant repeating the dermal exposure had detectable BPA-d in urine for 9 days, showed linear cumulative excretion over 5 days, and had detectable free BPA-d in serum. Proportions of free BPA-d in urine following dermal exposure (0.71%-8.3% of total BPA-d) were generally higher than following the dietary exposure (0.29%-1.4%). Compared to dietary BPA exposure, dermal absorption of BPA leads to prolonged exposure and may lead to higher proportions of unconjugated BPA in systemic circulation.

Dermal uptake of nicotine from air and clothing: Experimental verification

“…Excretion of nicotine and its metabolites (above generally observable background levels) continued throughout the entire period of urine collection. This observation supports earlier conclusions that skin acts as a reservoir for chemicals that accumulated during exposure and delivers them into the blood after exposure . Comparison of background nicotine and metabolite concentrations measured in the pre‐exposure samples collected in weeks 1 and 2 further supports this hypothesis.…”

“…This observation supports earlier conclusions that skin acts as a reservoir for chemicals that accumulated during exposure and delivers them into the blood after exposure. 7,24,25 Comparison of background nicotine and metabolite concentrations measured in the pre-exposure samples collected in weeks 1 and 2 further supports this hypothesis. The average concentrations of nicotine, cotinine, and 3OH-cotinine in the pre-exposure samples in week 1 were <LOD, 0.28, and 0.51 μg/L, respectively.…”

Flaws in design, execution and interpretation limit CLARITY‐BPA’s value for risk assessments of bisphenol A

“…5,6,69 Also, handling thermal receipt paper, coated with high amounts of bioactive BPA, results in high levels of BPA exposure, and markedly different pharmacokinetics (much higher serum levels for a longer period) compared with gavage exposure. [70][71][72] These findings challenge the FDA's assumption that only BPA exposure from food can be used to model exposure of people to BPA and to declare BPA safe based on estimates of BPA exposure only from food.…”

Erfassung der Humanexposition mit organischen Verbindungen in Innenraumumgebungen

“…berichteten über ähnliche Beobachtungen bei luftgetragenem Nikotin nach (trans)dermaler Exposition . In einer Studie mit isotopenmarkiertem Bisphenol A fanden Liu und Martin Spitzenkonzentrationen im Urin 1.0–5.5 h nach oraler Exposition, aber erst 15–34 h nach dermaler Exposition …”

“…Es ist bekannt, dass die Aufnahmewege (oral, dermal, inhalativ) einen Einfluss auf die Aufnahmeraten, die Verteilung und die Eliminierungskinetik haben. Sie können auch das Verhältnis und die Mengen der verschiedenen gebildeten und ausgeschiedenen Metaboliten beeinflussen . Dies ist von besonderer Bedeutung in toxikologischen oder mechanistischen Kontexten.…”