Properties, Potential Toxicity, and Transformations of VMSs in the Environment

Gaj, Kazimierz

doi:10.1007/698_2018_360

Cited by 5 publications

(2 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, these compounds can bioaccumulate in the living organisms [ 17 , 18 , 19 , 20 ], in the ecosystem with significant durability and the ability to transport to very remote areas, including the Arctic region [ 20 , 21 , 22 ]. This is mainly possible due to their physicochemical properties, such as high volatility (4.6–132 Pa at 25 °C), Henry’s law constant (1.210–4.945 kPa m 2 /mol at 25 °C), chemical stability [ 23 ], hydrophobicity (e.g., low water solubility: 5.3–56 mg/L), and high octanol-water partition coefficient (log Kow: 5.10–8.87 at 25 °C) [ 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Ex Vivo Human Skin is not a Barrier for Cyclic Siloxanes (Cyclic Silicones): Evidence of Diffusion, Bioaccumulation, and Risk of Dermal Absorption Using a New Validated GC-FID Procedure

Krenczkowska

Mojsiewicz‐Pieńkowska

Wielgomas

et al. 2020

Pharmaceutics

View full text Add to dashboard Cite

Cyclic methylsiloxanes D4, D5, D6 (also called cyclic silicones) are widely used in various dermatological products and cosmetics, both for children and adults. As a result of their unique physicochemical properties, the production of cyclic methylsiloxanes has greatly increased over the last few years, which has resulted in increased exposure to mankind. The validated quantitative for gas chromatography-flame ionization detector (GC-FID) analysis with using the transdermal diffusion system with vertical Franz cells demonstrated that ex vivo human skin is not a barrier to cyclic siloxanes. D4, D5, and D6 have a specific affinity to stratum corneum (SC) (especially D6), and can even diffuse into the deeper layers of the skin (epidermis (E) and dermis (D)), or into the receptor fluid as well. An important achievement of this work was the observation of the characteristic ratio partitioning D4, D5, and D6 in skin layers and receptor fluid (RF). The studies have shown that, in order to thoroughly understand the mechanism, it is important to determine not only the differences in the amounts of cumulated doses in total in all skin layers and receptor fluid, but also the mutual ratios of analyte concentrations existing between matrices. For example, in the case of the stratum corneum, the cumulative doses of D4, D5, and D6 were 27.5, 63.9, and 67.2 µg/cm2/24 h, respectively, and in the epidermis, they were 6.9, 29.9, and 10.7 µg/cm2/24 h, respectively, which confirmed the highest affinity of D6 to stratum corneum as the amount diffused into the epidermis was 2.8 times smaller compared to D5. The calculated epidermis-to-stratum corneum ratios of analyte concentrations also confirm this. The largest ratio was identified for D5 (E/SC = 47), followed by D4 (E/SC = 25), and finally by D6 (E/SC = 16). The analysis of the next stage of diffusion from epidermis to dermis revealed that in dermis the highest cumulative dose was observed for D5 (13.9 µg/cm2/24 h), while the doses of D4 and D6 were similar (5.1 and 5.3 µg/cm2/24 h). Considering the concentration gradient, it can be concluded that the diffusion of D5 and D6 occurs at a similar level, while D4 diffuses at a much higher level. These observations were also confirmed by the dermis-to-epidermis concentration ratios. The final stage of diffusion from dermis to the receptor fluid indicated that D4 was able to permeate easily, while D5 exhibited a difficult diffusion and the diffusion of D6 was limited. The receptor fluid-to-dermis concentration ratios (RF/D) were calculated for D4, D5, and D6: 80, 53, and 17, respectively. Our results also revealed the increased risk of D4 and D5 absorption into the blood and lymphatic systems, whereas D6 demonstrated the lowest risk. Therefore, we can argue that, among the three tested compounds, D6 is the safest one that can be used in dermatological, cosmetic, and personal care products. This study demonstrates that the stratum corneum, epidermis, and dermis can be also considered reservoirs of cyclic methylsiloxanes. Therefore, these compounds can demonstrate potential long-term bioaccumulation, and can be absorbed to the bloodstream in a long-term and uncontrolled process.

show abstract

Section: Introductionmentioning

confidence: 99%

Ex Vivo Human Skin is not a Barrier for Cyclic Siloxanes (Cyclic Silicones): Evidence of Diffusion, Bioaccumulation, and Risk of Dermal Absorption Using a New Validated GC-FID Procedure

Krenczkowska

Mojsiewicz‐Pieńkowska

Wielgomas

et al. 2020

Pharmaceutics

View full text Add to dashboard Cite

show abstract

“…It has been shown that only a small fraction (<1%) of VMSs convert to SiO 2 during biogas combustion [2]. The rest are emitted into the air, showing great potential for bioconcentration and bioaccumulation in the environment's various compartments [3]. In addition, microcrystalline silica (<100 nm), which is the oxidation product of VMSs, has carcinogenic and mutagenic properties [4].…”

Section: Introductionmentioning

confidence: 99%

Adsorptive Biogas Purification from Siloxanes—A Critical Review

Gaj

2020

Energies

Self Cite

View full text Add to dashboard Cite

Siloxanes are among the most technologically troublesome trace compounds present in biogas. As a result of their combustion, hard-to-remove sediments are formed, blocking biogas energy processing devices and reducing the efficiency of biogas plants. The purpose of this study was to help investors and designers to choose the optimal technology for the adsorptive removal of volatile methylsiloxanes (VMSs) from biogas and to identify adsorbents worth further development. This paper critically reviews and discusses the state-of-the-art technologies for the adsorption removal of siloxanes from biogas, indicating potentially beneficial directions in their development and deficiencies in the state of knowledge. The origin of VMSs in biogas, their selected physicochemical properties, technological problems that they can cause and their typical versus limit concentrations in biogases are presented. Both the already implemented methods of adsorptive VMSs removal from landfill and sewage gases and the ones being under development are verified and systematized. The parameters and effectiveness of adsorption processes are discussed, and individual adsorbents are compared. Possible ways of regenerating spent adsorbents are evaluated and prospects for their application are assessed. Finally, zeolite-based adsorbents—which can also be used for biogas desulfurization—and adsorbents based on polymer resins, as being particularly active against VMSs and most amenable to multiple regeneration, are identified.

show abstract

Seasonal occurrence, concentrations, and occupational exposure to VMSs in different environments of a WWTP

Sánchez-Soberón

Ratola

2022

Environmental Pollution

View full text Add to dashboard Cite

Properties, Potential Toxicity, and Transformations of VMSs in the Environment

Cited by 5 publications

References 58 publications

Ex Vivo Human Skin is not a Barrier for Cyclic Siloxanes (Cyclic Silicones): Evidence of Diffusion, Bioaccumulation, and Risk of Dermal Absorption Using a New Validated GC-FID Procedure

Ex Vivo Human Skin is not a Barrier for Cyclic Siloxanes (Cyclic Silicones): Evidence of Diffusion, Bioaccumulation, and Risk of Dermal Absorption Using a New Validated GC-FID Procedure

Adsorptive Biogas Purification from Siloxanes—A Critical Review

Seasonal occurrence, concentrations, and occupational exposure to VMSs in different environments of a WWTP

Contact Info

Product

Resources

About