Quantitative Exposure of Humans to an Octamethylcyclotetrasiloxane (D4) Vapor

Utell, Mark J.; Gelein, Robert; Yu, C.P.; Kenaga, C.; Geigel, Edgar J.; Torres, Alfonso; Chalupa, David; Gibb, F.R.; Speers, Donna M.; Mast, Richard; Morrow, Paul E.

doi:10.1006/toxs.1998.2483

Cited by 15 publications

(25 citation statements)

References 8 publications

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“…As previous studies indicated that inhalation F uptake for D4 and D5 was about 0.1 due to their low blood/air partition, 16,17 our study selected 0.1 as inhalation F uptake for cyclic compounds (D4−D6). Due to lack of specific F uptake for linear compounds, 1.0 was selected as F uptake for L3−L16.…”

Section: Methodsmentioning

confidence: 99%

“…Several groups have measured methyl siloxane concentrations in human plasma in controlled human exposures, such as the reports on octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) concentrations in plasma after 1-h exposures via inhalation (122 and 153 μg/L for D4 and D5, respectively.) 16,17 However, to our knowledge, there are no reports on methyl siloxane concentrations in the plasma of general or highly exposed populations in P.R. China or other countries.…”

Section: Introductionmentioning

confidence: 97%

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Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Shi

Wang

et al. 2012

Environ. Sci. Technol.

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In this study, we systematically investigated methyl siloxanes (D4−D6, L3−L16) exposure to workers from and residents living near a siloxanes manufacturing facility by measuring their concentrations in both environmental matrices (air, dust/soil, n = 62) and human plasma samples (n = 201). For the seventeen target compounds, the average concentrations in indoor matrixes from six workshops of the facility ranged from 0.6 μg/m 3 to 2.7 mg/m 3 in air samples and from 0.36 μg/g to 1.16 mg/g in dust samples, which were 3−5 orders of magnitudes higher than those levels at the reference zone. In plasma samples from the current workers in six workshops and residents living near the facility, the average concentrations of methyl siloxanes were 5.61−451 and 4.56− 13.5 ng/g, respectively, which were 1−2 magnitudes higher than those in the reference group. Plasma methyl siloxanes concentrations of people from different workshops were positively correlated with their exposure levels, indicating that high occupational exposure in siloxane production process elevated human plasma concentrations. However, there was no significant correlation between human plasma concentrations with their duration of occupation. These methyl siloxanes were eliminated from human plasma with half-lives ranging from 2.34 to 9.64 days, which increased with the increasing number of Si−O bonds for most analogues.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Shi

Wang

et al. 2012

Environ. Sci. Technol.

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“…Single-exposure studies in animals are available for all relevant routes. Utell et al (1998) report no adverse effects on human volunteers exposed to 10 ppm D4 for one hour. Dow Corning (2000e) reports no adverse effects on volunteers administered a 24-hour non-occlusive dermal application of 1 or 1.4 g to the underarms.…”

Section: Acute Toxicitymentioning

confidence: 88%

“…In human volunteers who inhaled 10 ppm D4 for one hour there was no evidence of sensory respiratory irritation (Utell et al, 1998).…”

Section: Irritationmentioning

confidence: 98%

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Temperature Dependence of the Organic Carbon/Water Partition Ratios (K_OC) of Volatile Methylsiloxanes

Panagopoulos

Jahnke

Kierkegaard

et al. 2017

Environ. Sci. Technol. Lett.

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Knowing the temperature dependence of the organic carbon/water partition ratios (K OC ) of volatile methylsiloxanes (VMS) is required to understand their environmental fate. We measured the K OC of two linear VMS (lVMS), three cyclic VMS (cVMS), and six polychlorinated biphenyls (PCBs) at 25, 15, 10, and 5 °C and calculated their enthalpies and entropies of sorption to organic carbon (ΔH OC and ΔS OC , respectively). The ΔH OC of VMS ranged from −79.2 to −45.8 kJ mol −1 , while the ΔH OC of the PCBs ranged from −68.7 to −29.3 kJ mol −1 . Previously reported measurements of the enthalpy of phase change between octanol and water (ΔH OW ) for cVMS (11.3−68.8 kJ mol −1 ) differed substantially from our ΔH OC measurements, even showing different signs (negative versus positive). Literature data of ΔH OC and ΔH OW for PCBs (−61 to −17 kJ mol −1 ) are closer to our measured values of ΔH OC for the PCBs showing the same sign (negative) with differences within a factor of 2 in the majority of the cases. Comparison of all available data for PCBs and VMS indicated that there may be important differences between ΔH OC and ΔH OW , especially for the VMS. Therefore, assuming ΔH OC equals ΔH OW in environmental fate models may be a source of substantial error.

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Acute Respiratory Exposure of Human Volunteers to Octamethylcyclotetrasiloxane (D4): Absence of Immunological Effects

Looney

Frampton

Byam

et al. 1998

Toxicological Sciences

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Quantitative Exposure of Humans to an Octamethylcyclotetrasiloxane (D4) Vapor

Cited by 15 publications

References 8 publications

Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Temperature Dependence of the Organic Carbon/Water Partition Ratios (K_OC) of Volatile Methylsiloxanes

Acute Respiratory Exposure of Human Volunteers to Octamethylcyclotetrasiloxane (D4): Absence of Immunological Effects

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Quantitative Exposure of Humans to an Octamethylcyclotetrasiloxane (D4) Vapor

Cited by 15 publications

References 8 publications

Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Methyl Siloxanes in Environmental Matrices around a Siloxane Production Facility, and Their Distribution and Elimination in Plasma of Exposed Population

Temperature Dependence of the Organic Carbon/Water Partition Ratios (KOC) of Volatile Methylsiloxanes

Acute Respiratory Exposure of Human Volunteers to Octamethylcyclotetrasiloxane (D4): Absence of Immunological Effects

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Temperature Dependence of the Organic Carbon/Water Partition Ratios (K_OC) of Volatile Methylsiloxanes