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Methyl siloxanes in barbershops and residence indoor dust and the implication for human exposures
Nannan Liu1, Lin Xu2, Yaqi Cai3
1State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China; School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China.
Abstract:
Methyl siloxanes (MSs) have been widely added as emollients or solvents in various personal care products (PCPs) such as soap, shampoo and hair conditioner. A considerable percentage of MSs are released into the atmosphere directly from the use of PCPs in indoor environments. Indoor dust is a major reservoir of MSs, due to their particle-binding affinity. Dust ingestion could be one exposure pathway for special populations (hairdressers, for example). Though the toxicity of MSs is known, there is no information regarding the occurrence of MSs in barbershop dusts and the exposure of hairdressers through indoor dust ingestion. In the present study, the levels of three cyclic siloxanes (D4-D6) and 13 linear siloxanes (L4-L16) were measured in indoor dust samples collected from barbershops, and some other microenvironment including bathhouses, dormitories and households for comparison. The concentrations of ∑MSs in barbershop dusts were one to two orders of magnitude higher than those from the other three indoor microenvironments. The daily intakes of ∑MSs through indoor dust ingestion were estimated using the model of worst-case exposure (95th percentile concentration) and high dust ingestion, For the hairdressers in workplaces (barbershops), the exposure rates were 14.3ng/kg-bw/day, and for the general population, college students and toddlers (1-3yr), the corresponding exposure rates in living spaces were 3.43, 2.00 and 222ng/kg-bw/day, respectively. Such high exposure levels of MSs through dust ingestion indicate that we should not overlook the potential health risks for occupational groups and toddlers.
Insights
Methyl siloxanes (MSs) in indoor dust pose risks, especially for hairdressers. Barbershop dust showed significantly higher MS concentrations, indicating potential occupational health concerns for this group and toddlers.
Area of Science:
- Environmental Science
- Toxicology
- Occupational Health
Background:
- Methyl siloxanes (MSs) are common in personal care products (PCPs) and released indoors.
- Indoor dust acts as a reservoir for MSs due to their binding affinity.
- Occupational groups like hairdressers may be exposed via dust ingestion.
Purpose of the Study:
- To quantify methyl siloxane (MS) levels in barbershop dust.
- To assess MS exposure in hairdressers and compare with other populations.
- To evaluate potential health risks from MSs in indoor dust.
Main Methods:
- Collected indoor dust from barbershops, bathhouses, dormitories, and households.
- Measured concentrations of cyclic (D4-D6) and linear (L4-L16) siloxanes.
- Estimated daily MS intake through dust ingestion using worst-case exposure models.
Main Results:
- Barbershop dust had MS concentrations 1-2 orders of magnitude higher than other microenvironments.
- Estimated daily MS intake for hairdressers was 14.3 ng/kg-bw/day.
- Toddlers showed the highest estimated daily intake at 222 ng/kg-bw/day.
Conclusions:
- Barbershop dust is a significant source of MS exposure for hairdressers.
- High MS exposure levels in dust warrant attention for occupational groups and toddlers.
- Potential health risks associated with MSs in indoor dust require further investigation.
