In this study,five cyclic D3–D7 and nine linear siloxanes L3–L11 were determined in 60 indoor air samples collected in Albany, New York, USA.. The mean concentrations of individual siloxa
Trang 1Occurrence of cyclic and linear siloxanes in indoor air from Albany,
New York, USA, and its implications for inhalation exposure
a
Wadsworth Center, New York State Department of Health, Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O Box 509, Albany, NY 12201-0509, United States
b
Faculty of Chemistry, Hanoi University of Science, Vietnam National University, 19 Le Thanh Tong, Hoan Kiem, Hanoi, Viet Nam
c
Biochemistry Department, Faculty of Science and Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
H I G H L I G H T S
• Cyclic and linear siloxanes were determined in 60 indoor air samples
• Concentrations of 14 siloxanes ranged from 249 to 6210 ng/m3with the highest levels in salons
• High molecular weight siloxanes were preferably sorbed in particulate phase of indoor air
• Inhalation exposure dose to siloxanes ranged from 0.27 to 3.18 μg/kg-bw/d
a b s t r a c t
a r t i c l e i n f o
Article history:
Received 10 October 2014
Received in revised form 7 December 2014
Accepted 8 December 2014
Available online xxxx
Editor: Adrian Covaci
Keywords:
Siloxane
Indoor air
Inhalation exposure
PDMS
Cyclic methylsiloxane
D5
Cyclic and linear siloxanes are used in a wide variety of household and consumer products Nevertheless, very few studies have reported the occurrence of these compounds in indoor air or inhalation exposure to these compounds
In this study,five cyclic (D3–D7) and nine linear siloxanes (L3–L11) were determined in 60 indoor air samples collected in Albany, New York, USA The mean concentrations of individual siloxanes in particulate and vapor phases ranged fromb12 μg g−1(for octamethyltrisiloxane [L3], decamethyltetrasiloxane [L4]) to 2420μg g−1 (for decamethylcyclopentasiloxane [D5]) and from 1.05 ng m−3to 543 ng m−3, respectively The mean concentra-tions of individual siloxanes in combined particulate and vapor phases of bulk indoor air ranged from 1.41 ng m−3 (for L4) to 721 ng m−3(for D5) Cyclic siloxanes hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), D5, dodecamethylcyclohexasiloxane (D6), and octadecamethylcycloheptasiloxane (D7) were found in all in-door air samples The mean concentrations of total siloxanes (i.e., sum of cyclic and linear siloxanes) ranged from
249 ng m−3in laboratories to 6210 ng m−3in salons, with an overall mean concentration of 1470 ng m−3in bulk indoor air samples The calculated mean daily inhalation exposure doses of total siloxanes (sum of 14 silox-anes) for infants, toddlers, children, teenagers, and adults were 3.18, 1.59, 0.76, 0.34, and 0.27μ g/kg-bw/day, respectively
© 2014 Elsevier B.V All rights reserved
1 Introduction
Siloxanes are organo-silicone compounds and consist of– (CH3)2SiO
– structural units Two major groups of siloxanes of commercial
signifi-cance are cyclic and linear siloxanes Siloxanes are used in a wide variety
of consumer and industrial products (Horii and Kannan, 2008; Ortega
and Subrenat, 2009) Personal care products contain siloxanes at
con-centrations on the order of several percentages by weight (Horii and
Kannan, 2008; Wang et al., 2009) Cyclic siloxanes– D4, D5, D6, and
D7– were found in consumer products at mean concentrations of
9380, 81,800, 43,100, and 846 μg g−1 respectively; skin lotions contained total linear siloxanes at concentrations (sum of L4 to L14)
as high as 73,000μg g−1 (i.e., 7.3% by weight;Horii and Kannan,
2008) The total cyclic siloxane concentrations (D6 to D25) in silicon-ized rubber products marketed for food contact use were in the range
of 3310 to 14,700μg g−1(Kawamura et al., 2001)
Studies have reported the occurrence of siloxanes in a wide range of environmental samples, including outdoor air, water, wastewater, in-door dust, soil, landfill biogas, sediment, sewage sludge, and biota, in-cluding humans (Wang et al., 2001, 2013a,2013b; Badjagbo et al., 2010; Kierkegaard and McLachlan, 2010; Sánchez-Brunete et al., 2010; Zhang et al., 2011; Bletsou et al., 2013; Blanchard et al., 2014; Cortada et al., 2014; Lee et al., 2014) A recent review has summarized environmental occurrence of cyclic siloxanes (Wang et al., 2013a)
Science of the Total Environment 511 (2015) 138–144
⁎ Corresponding author at: Wadsworth Center, Empire State Plaza, PO Box 509, Albany,
NY 12201-0509, USA.
E-mail address: Kurunthachalam.Kannan@health.ny.gov (K Kannan).
http://dx.doi.org/10.1016/j.scitotenv.2014.12.022
Contents lists available atScienceDirect
Science of the Total Environment
j o u r n a l h o m e p a g e :w w w e l s e v i e r c o m / l o c a t e / s c i t o t e n v
Trang 2Accumulation of D5 infish from the arctic environment has been shown
(Warner et al., 2010)
Despite the use of siloxane-containing products in the indoor
envi-ronment and the volatility of siloxanes, very few studies have reported
the occurrence of these compounds in indoor air (Shields et al., 1996;
Latimer et al., 1998; Kaj et al., 2005; Companioni-Damas et al., 2014)
One study reported the occurrence of cyclic and linear siloxanes in
in-door air samples collected from the UK and Italy, at concentrations as
high as 170μg m−3(Pieri et al., 2013) Another study reported a median
concentration of 2200 ng m−3for the sum of D4, D5, and D6
concentra-tions in indoor air samples from Chicago, Illinois, USA (Yucuis et al.,
2013) A guidance value of 4000μg m−3and a precautionary guideline
value of 400μg m−3were recommended for the sum of D3 to D6 in
in-door air in Germany (GermanEnvironment Agency, 2011)
Studies have reported reproductive and endocrine effects of
silox-anes in laboratory animals Estrogenic and androgenic activities of D4
and/or D5 have been reported in rats (McKim et al., 2001; Quinn et al.,
2007b) A recent article has reviewed the toxicity of cyclic siloxanes
(Wang et al., 2013a) The potential of D4 to suppress the
pre-ovulatory luteinizing hormone surge and ovulation has been shown in
laboratory rodent studies (Quinn et al., 2007a).Meeks et al (2007)
showed that a single dose of D4 on the day prior to mating resulted in
a significant reduction in fertility in female rats A dose-dependent
in-crease in uterine weights in ovariectomized mice and an inin-crease in
uterine peroxidase activity were shown in D4-exposed mice (He et al.,
2003) Inhalation exposure of rats to D5 did not alter humoral immunity
and caused only minor, transient changes in hematological, clinical, and
anatomical parameters (Burns-Naas et al., 1998) Several
environmen-tal risk assessment studies conducted in Canada, Sweden and the UK
suggested that methylsiloxanes are persistent and can pose harmful
ef-fects on the environment (Kaj et al., 2005; Environment Canada, 2008;
Brooke et al., 2009)
Siloxanes are ubiquitous in the environment, and potential exists for
contamination in laboratories and sampling devices, which imposes
challenges in the collection and analysis of siloxanes in environmental
samples A few studies have reported the methods to collect siloxanes
in air (Wang et al., 2001; Badjagbo et al., 2009; Kierkegaard and
McLachlan, 2010; Yucuis et al., 2013; Pieri et al., 2013;
Conpanioni-Damas et al., 2014) In this study, by use of a combination of quartz
fiber filters and polyurethane foam (PUF) plugs, we collected indoor
air samples by a low-volume air sampler at various indoor
environ-ments including homes, offices, schools, salons and public places The
objectives of this study were to determinefive cyclic and nine linear
si-loxanes in both particulate and vapor phases of indoor air in Albany,
New York, USA Inhalation exposure of humans to siloxanes was also
estimated
2 Materials and methods
2.1 Standards
Hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane
(D4), decamethylcyclopentasiloxane (D5), and
dodecamethylcyclo-hexasiloxane (D6), with a purity ofN95%, were purchased from Tokyo
Chemical Industry, Inc (Wellesley Hills, MA, USA)
Octamethyltri-siloxane (L3) (98%), decamethyltetraOctamethyltri-siloxane (L4) (97%), and
dodeca-methylpentasiloxane (L5) (97%) were purchased from Sigma-Aldrich
(St Louis, MO, USA) Polydimethylsiloxane (PDMS) 200fluid (viscosity
of 5 cSt) that contained octadecamethylcycloheptasiloxane (D7), linear
tetradecamethylhexasiloxane (L6), and other polydimethylsiloxanes
(L7, L8, L9, L10, and L11) were purchased from Sigma-Aldrich
(Table S1) Tetrakis (trimethylsiloxy)-silane (M4Q) of 97% purity was
from Aldrich, and 13C-labeled
decamethylcyclopentasiloxane-[2,4,6,8,10-13C5] (13C-D5) of 98% purity was from Bristlecone
Biosci-ences, Inc (Brea, CA, USA), and these two compounds were used as
surrogate standards All standards were dissolved in hexane The
composition of PDMS was determined and reported in our previous study (Horii and Kannan, 2008) and the PDMS mixture was used in the determination of concentrations of linear siloxanes
2.2 Sample collection and preparation PUF plugs (ORBO-1000 PUF dimensions: 2.2 cm O.D × 7.6 cm length) were from Supelco (Bellefonte, PA, USA) For the analysis of background levels of siloxanes, PUF plugs were extracted twice with 100 mL mixture
of dichloromethane (DCM) and hexane (3:1, v:v) and analyzed by gas chromatography–mass spectrometry (GC–MS) It was found that each
of the newly purchased PUF plugs contained D3, D4, D5, D6, and D7 at 6.03 ± 4.72 ng, 19.9 ± 6.59 ng, 32.2 ± 12.5 ng, 7.44 ± 3.05 ng, and 4.18 ± 2.19 ng, respectively (n = 5) Therefore, all PUF plugs required additional cleaning prior to use PUFs were purified by shaking with
100 mL mixture of DCM and hexane (3:1, v:v) for 30 min This proce-dure was performed twice The cleaned PUFs were wrapped in solvent rinsed aluminum foil, stored in a glass jar, and kept in an oven at 100 °C until sampling The quartzfiber filters (Whatman, grade QM-A, pore size: 2.2μm with a particle retention rating at 98% efficiency in liquid,
32 mm diameter) were prepared by heating at 450 °C for 20 h The puri-fied quartz fiber filters were kept in an oven at 100 °C until use The quartz fiber filters were weighed in an analytical balance (to nearest 0.01 mg) before and after the collection of air samples for the determination of par-ticle content
Two PUF plugs were packed in tandem in a glass tube (ACE glass, 2.2 cm O.D × 25 cm length), and the quartzfiber filter was held with a
Teflon cartridge (Supelco, PUF filter cartridge assembly, cat no 21031) on top of the glass tube packed with PUF plugs All glassware used for sampling and analysis was rinsed with acetone and hexane and heated at 450 °C immediately prior to use
Indoor air samples were collected for 12 to 24 h by a low-volume air sampler (LP-20; A.P Buck Inc., Orlando, FL, USA) at aflow rate of 5 L per minute The total volume of air collected from each location ranged from 3.6 m3to 7.2 m3 Air samples (both PUFs andfilters) were kept
at−18 °C until analysis The samples were kept for no longer than 3 weeks for analysis The samples were collected from March to May
2014 at several locations in Albany, New York, USA The sampling loca-tions were grouped into six categories: homes (n = 20), offices (n = 7), laboratories (n = 13), schools (n = 6), salons (n = 6, hair and nail sa-lons), and public places (n = 8, e.g., shopping malls)
Prior to analysis, samples (both PUFs andfilters) were spiked with
100 ng of M4Q and13C-D5 as surrogate standards PUF plugs were ex-tracted by shaking in an orbital shaker (Eberbach Corporation, Ann Arbor, MI, USA) with DCM and hexane (3:1, v:v) for 30 min The extrac-tion was performed twice, with 100 mL of solvent mixture for thefirst extraction and 80 mL for the second The extracts were concentrated
in a rotary evaporator at 40 °C to approximately 5 mL The solution was then transferred into a 12-mL glass tube and concentrated by a gen-tle stream of nitrogen to exactly 1 mL and transferred into a GC vial The particulate samples were extracted by shaking glassfiber filters with a mixture of DCM and hexane (3:1; 20 mL; v:v) each time for
5 min, which was performed three times The extract was concentrated
in a rotary evaporator and then by a gentle stream of nitrogen to exactly
1 mL The extract was then transferred into a GC vial
2.3 Instrumental analysis Analysis was performed on an Agilent Technologies 6890 gas chro-matograph (GC) interfaced with a 5973 mass spectrometer (MS) Separation of siloxanes was achieved by HP-5MS capillary column (Agilent, Santa Clara, CA, USA; 5% diphenyl 95% dimethylpolysiloxane,
30 m × 0.25 mm i.d × 0.25μm film thickness) Samples were injected
in the splitless mode, and the injection volume was 2μL The oven temperature was programmed from 40 °C (held for 2 min) to 220 °C
at 20 °C/min, increased to 280 °C at 5 °C/min (held for 10 min), and
Trang 3held for 5 min at 300 °C Ion fragment m/z 207 was monitored for D3, m/z
281 for D4, D7, and L5, m/z 355 for D5, and m/z 341 for D6 Ion fragment
m/z 147 was used for confirmation of L6 and L7 Ion fragment m/z 207 was
monitored for confirmation of L4 and m/z 221 for the other siloxanes
(Horii and Kannan, 2008; Badjagbo et al., 2009; Zhang et al., 2011;
Bletsou et al., 2013) Ion fragment m/z 281 was monitored for M4Q and
m/z 360 for13C-D5
2.4 Quality assurance and quality control
Siloxanes are present in several laboratory products, which have
been examined in our previous study (Horii and Kannan, 2008) Efforts
were taken to minimize background levels of siloxane contamination in
our analysis All glassware was heated for 20 h at 450 °C prior to use
Sol-vents were used directly from glass bottles, and exposure of solvent to
air was kept minimal GC vials were capped in an aluminum foil (instead
of rubber septum) Procedural blanks were analyzed with every set of 8
samples D3, D4, D5, and D6 levels in procedural blanks were 3.31 ±
0.91 ng, 4.2 ± 2.46 ng, 7.18 ± 3.52 ng, and 1.8 ± 0.36 ng, respectively
Other siloxanes were not detected in the procedural blanks The
con-tamination of siloxanes in procedural blanks is from solvents, glassware,
or residual levels present in PUFs (after purification) The reported
con-centrations in indoor air samples were subtracted by the average values
found for the procedural blanks The calibration curve was linear over a
concentration range of 1 ng/mL to 500 ng/mL for individual siloxanes
(R2N 0.995) Duplicate samples were collected in three locations and
the relative standard deviation (RSD) of measured concentrations was
b10%
A total of 100 ng of M4Q and13C-D5, D3, D4, D5, D6, L3, L4, and L5
were spiked into blank PUF plugs and a glassfiber filter and passed
through the entire analytical procedure The recoveries of target
com-pounds spiked into PUFs andfilters are shown inTable 1 The recoveries
of M4Q spiked into samples ranged from 90.8 to 116% (mean: 101%;
RSD: 8.7%) in the particle phase and from 87.5 to 120% (mean: 104%;
RSD: 10.4%) in the vapor phase The method detection limit (MDL)
and the method quantification limit (MQL) were determined on the
basis of an average volume of air collected, which was 3.6 m3; the
aver-age weight of airborne particle collected, which was 0.25 mg, and the
lowest point in the calibration standard with a signal-to-noise ratio of
3 and 10, respectively The sample concentration/dilution factors were
included in the calculation of MDL and MQL For the vapor phase, the
MQL ranged from 0.22 to 2.22 ng m−3, and, for the particulate phase,
the MQL ranged from 3.2 to 32 ng g−1 The mean recoveries of four
cyclic and three linear siloxanes in gas and particulate phases were from 73.4 to 116%, with an RSD of 7.3 to 15.6% (Table 1) For values below the MQL, the concentrations were set at one-half of the MQL for statistical analysis Statistical analysis was conducted through Microsoft Excel (Microsoft Office 2010) and GraphPad Prism version 5.0 Statisti-cal significance was set at p b 0.05
3 Results and discussion 3.1 Concentrations of siloxanes in particulate phase The concentrations of individual siloxanes in the particulate phase (Table 2) were calculated based on the weight of the airborne particle collected in a glassfiber filter (that ranged from 0.15 mg to 0.45 mg) D3, D4, D5, D6, and D7 were found in all samples, whereas L3 and L11 were detected in only 26.7% and 8.33% of the samples, respectively L5
to L9 were found frequently in samples (75% to 95%) at high concentra-tions, whereas L3, L4, and L11 were rarely detected Among various si-loxanes analyzed, D5 and L8 were the most abundant compounds in the particulate phase The concentrations of D5 in the particulate phase ranged from 29.3 to 34,300μg g−1(mean: 2420) and the concen-trations of L8 ranged from below MQL to 12,700μg g−1(mean: 1320) The air volume based measurements (ng m−3) of siloxanes in the par-ticulate phase of indoor air are shown as the supporting information (Table S2)
Because airborne particles are a source of indoor dust after deposi-tion, concentrations of siloxanes measured in airborne particles were compared with those reported in indoor dust The concentrations of si-loxanes in airborne particles were four times higher than the concentra-tions reported in indoor dust from China (Lu et al., 2010) The sum of mean concentration offive cyclic and nine linear siloxanes in the partic-ulate phase of indoor air was 6000μg g−1(i.e., approximately 0.6% by weight) The highest concentrations of siloxanes were found in salons Personal care products are the major sources of siloxanes in the indoor environment (Horii and Kannan, 2008; Wang et al., 2009), which ex-plains the elevated concentrations found in air samples from salons 3.2 Concentrations of siloxanes in vapor phase
The concentrations of siloxanes in the vapor phase of indoor air are shown inTable 3 The concentrations of D4, D5, and D6 were higher in the vapor phase than in the particulate phase (Fig 1) Higher concentra-tions of these three siloxanes in the vapor phase than in the particulate
Table 1
The method detection limit, quantitation limit and the recoveries of siloxanes through the analytical method used in this study.
Recoveries, % (n = 8) Recoveries, % (n = 8)
MDL (ng m−3) MQL (ng m−3) Range Mean RSD MDL (ng g−1) MQL (ng g−1) Range Mean RSD D3 0.06 0.22 66.0–84.9 73.4 7.3 0.8 3.2 77.5–105 91.2 9.8 D4 0.08 0.28 85.4–121 105 13.1 1.2 4.0 86.6–119 106 11.8 D5 0.06 0.22 88.7–126 109 14.7 0.8 3.2 98.4–125 116 8.6 D6 0.06 0.22 93.9–123 109 11.9 0.8 3.2 80.7–115 99.7 12.2
L3 0.14 0.83 75.5–110 93.9 10.6 2.0 12.0 79.5–112 96.9 12.0 L4 0.14 0.83 93.6–123 112 12.7 2.0 12.0 78.0–122 104 15.6 L5 0.14 0.56 82.5–116 103 11.9 2.0 8.0 96.9–120 110 8.7
13
Method detection limit (MDL) and method quantitation limit (MQL) were calculated on the basis of the average volume of air collected which was 3.6 m 3
and the average weight of
air-140 T.M Tran, K Kannan / Science of the Total Environment 511 (2015) 138–144
Trang 4Concentrations of individual siloxanes in the particulate phase of indoor air samples collected from various locations in Albany, New York, USA (μg g ).
Freq %: frequency of siloxanes detectable in particulate phase n.d.: not detectable “b”: below the limit of quantification of the method Σ Sil.: the total concentrations of all siloxanes D3–D7 and L3–L11
Table 3
Concentrations of individual siloxanes in the vapor phase of indoor air samples collected from various locations in Albany, New York, USA (ng.m−3).
n.d.: not detectable Freq %: frequency of siloxanes detectable in indoor air “b”: below the limit of quantification of the method Σ Sil.: the total concentrations of all siloxanes D3–D7 and L3–L11
Trang 5phase can be explained by their high vapor pressure (seeLatimer et al.,
1998) However, it should be noted several environmental factors
in-cluding temperature, relative humidity, and amount and type of
partic-ulate matter can affect partitioning of siloxanes in air (Latimer et al.,
1998) Further discussion regarding gas-particle partitioning (Kp) of
si-loxanes can be found in the Supporting information (Table S3)
The mean ratio for concentrations of D4 between vapor and
particu-late phases was 4.7, and this ratio was 3.0 and 3.8 for D5 and D6,
respec-tively In contrast, the high molecular weight siloxanes such as L8 and L9
were found more frequently in the particulate phase Among all
micro-environments studied, L8 and L9 concentrations were 6 and 70 times,
respectively, higher in the particulate phase than in the vapor phase
L10 and L11 were detected only in the particulate phase of all samples
High molecular weight siloxanes have low vapor pressures, which
ex-plain the preferential partitioning of L10 and L11 to the particulate
phase It is also worth to note that retention of siloxanes onto glass
fiber filter from vapor phase during sampling is not known
3.3 Siloxanes in bulk indoor air (particulate plus vapor phases)
Total concentrations of individual siloxanes in indoor air were
deter-mined by summation of concentrations measured in the particulate and
vapor phases on a volumetric (m3) basis (Table 4) The mean
concentra-tion of siloxanes was the highest in indoor air samples collected from
hair salons and the lowest in laboratories (Fig 2) Eleven of the 14 target
siloxanes were found in all samples from hair salons L3, L4, L10, and L11
were found less frequently in the air samples The mean concentration
of siloxanes found in hair salons was 6210 ng m−3; the next highest
concentration was in samples from the public places (1990 ng m−3)
and schools (1240 ng m−3) The mean total concentration of siloxanes
in hair salons was 25 times higher than the lowest value of
249 ng m−3found in laboratories and 4 times higher than the total
mean value for all samples (1470 ng m−3) As indicated above, high
concentrations in siloxanes in salons can be explained by the extensive
use of personal care products in hair salons The total mean
concentra-tion of siloxanes found in our study is similar to that reported
by Yucuis et al (2013), who found a median concentration of
2200 ng m−3for the sum of D4, D5, and D6 in indoor air (in laboratories
and offices) from Chicago, Illinois, USA However, our values are much
lower than those of the mean concentrations of eight siloxanes in indoor
air (in homes, offices, and supermarkets) reported from Italy and the UK (18 to 240μg m−3for Italy and from 78 to 350μg m−3for the UK) (Pieri
et al., 2013).Companioni-Damas et al (2014)reported D5 concentra-tions as high as 293,000 ng m−3in homes and 2850 ng m−3in labora-tories in Barcelona, Spain
3.4 Contribution of D4 and D5 to total siloxane concentrations in indoor air Among several siloxanes, D4 and D5 were the most widely stud-ied compounds D4 and D5 were found at the high concentrations
in indoor air from Albany and ranged from 6.19 to 752 ng m−3for D4 (mean: 116 ng m− 3) and from 19 to 5130 ng m− 3for D5 (mean: 721 ng m− 3) The sum concentrations of D4 and D5 accounted for≥82% of the total of five cyclic siloxanes determined
in our study.Yucuis et al (2013)reported D4 levels in indoor air from the Seamans Center for Engineering Arts and Sciences at the University of Iowa (23 to 500 ng m−3); these values are similar to what was found in indoor air from Albany The D5 concentrations
at a Swedish rural site ranged from 0.7 to 8 ng m− 3(Kierkegaard and McLachlan, 2010), which were much lower than the concentra-tions found in our study
The ratios of D5 to D4 concentrations have been used in the determi-nation of sources of cyclic siloxanes in the environment (Navea et al., 2011; Yucuis et al., 2013) The D5/D4 ratios in indoor air from Albany were 7.86, 5.68, 1.90, 6.56, 6.45, and 5.73 for homes, offices, laboratories, schools, hair salons, and public places, respectively The D5/D4 ratios in indoor air were similar among thefive categories of sampling locations, except for the laboratory locations, which had the lowest values (1.90) High D5/D4 ratios in indoor environments suggest the existence of point sources of cyclic siloxanes Personal care and household products are the sources of siloxanes in indoor air The mean concentrations of D5
in personal care products were much higher than those of D4 (2890μg g−1for D5 and 141μg g−1for D4) (Horii and Kannan, 2008) For the entire sample set of 60 indoor air samples, the ratio of D5/D4 was 6.21 The D5/D4 ratios were reported to range from 2.6 to 4.4 for in-door air samples in three types of commercial buildings in the USA (Shields et al., 1996) A recent study reported that the D5/D4 ratios av-eraged 91 and 3.2 for indoor and outdoor air, respectively (Yucuis et al.,
2013)
Fig 1 Concentrations of individual siloxanes in the vapor and particulate phases of indoor air (n = 60) from Albany, New York, USA.
142 T.M Tran, K Kannan / Science of the Total Environment 511 (2015) 138–144
Trang 63.5 Human exposure to siloxanes via inhalation
On the basis of the average inhalation rate of 13 m3day−1(CEPA, 1994; Pieri et al., 2013), we calculated the inhalation exposure to silox-anes by multiplying the measured concentration (ng m−3) with the vol-ume of air inhaled (m3) The results showed that the mean value of exposure of total siloxanes from homes, offices, laboratories, schools, sa-lons, and public places were 13,500, 6630, 3230, 16,200, 80,700, and 25,900 ng day−1, respectively The inhalation exposure dose for people
in salons was the highest (80,700 ng day−1) The mean daily exposure
to total siloxanes from all locations was 19,100 ng day−1 Among
sever-al siloxanes measured, D5 exposure was the highest and ranged from
247 to 66,700 ng day−1(mean: 9370 ng day−1) The average inhalation exposure doses for L8, L7, D4, and D6 were 1990, 1650, 1510, and
1470 ng day−1, respectively
No previous studies have reported human exposure doses of silox-anes by age Because the average body weights vary with age, infants (b1 yr): 6 kg-bw, toddlers (1–3 yr): 12 kg-bw, children (3–11 yr): 25 kg-bw, teenagers (11–18 yr): 57 kg-bw, and adults: 72 kg-bw (U.S En-vironmental Protection Agency Child-Specific Exposure Factors Hand-book, 2008), the calculated exposure doses of total siloxanes for infants, toddlers, children, teenagers, and adults were 3.18, 1.59, 0.76, 0.34, and 0.27μg/kg-bw/day, respectively D5 contributed to the highest daily exposures, with 1.56, 0.78, 0.37, 0.16, and 0.13μg/kg-bw/day for infants, toddlers, children, teenagers, and adults, respectively It is worth to note that our exposure doses are approximate values as these are based on average concentrations found in various microenvi-ronments Furthermore, a study byUtell et al (1998)reported that only 12% of the inhaled D4 dose was absorbed in systemic circulation and such information may be taken into account when calculating actual ex-posure doses However, high doses of inhalation exex-posure to D4 used in that study may underestimate absorbed fraction of D4
Jovanovic et al (2008)reported that the dermal exposure to cyclic siloxanes present in lotions and antiperspirants in the United States was 0.1 and 0.2 mg day−1, respectively; siloxane exposure doses from indoor air calculated in our study were similar to the exposure doses calculated from skin lotions and antiperspirants Nevertheless, based
on a comprehensive analysis of a wide range of personal care products,
Horii and Kannan (2008)showed that the daily exposure rate to total si-loxanes from personal care products (inhalation, ingestion, and dermal absorption pathways) was 307 mg day−1for the United States women and D5 contributed 162 mg day−1 The inhalation exposure doses of si-loxanes calculated in our study were lower than the values reported in
4 concentration
3 )
Fig 2 Mean concentrations of total siloxanes (vapor plus particulate phases) in indoor air samples from six categories of sampling locations in Albany, New York, USA.
Trang 7the UK (Pieri et al., 2013); the reported siloxane exposure doses for
chil-dren and adults in the UK were 3.19 and 1.88 mg day−1, respectively
4 Conclusions
Five cyclic and nine linear siloxanes were determined in 60 indoor
air samples from Albany, New York, USA; most siloxanes were found
in almost all indoor air samples, and D3, D4, D5, and D6 were found in
all samples Indoor air from hair salons contained the highest
concentra-tions of siloxanes (mean: 6210 ng.m−3) D5 was the most abundant
compound in indoor air samples (mean: 721 ng.m−3) High molecular
weight siloxanes (L7, L8, and L9) existed predominantly in the
particu-late phases than in the vapor phases The estimated average inhalation
exposure dose to total siloxanes in indoor air was 19,100 ng day−1
Acknowledgments
We thank Anthony M DeJulio for the help with sampling
Appendix A Supplementary data
Supplementary data to this article can be found online athttp://dx
doi.org/10.1016/j.scitotenv.2014.12.022
References
Badjagbo, K., Furtos, A., Alaee, M., Moore, S., Sauvé, S., 2009 Direct analysis of volatile
methylsiloxanes in gaseous matrixes using atmospheric pressure chemical
ioniza-tion–tandem mass spectrometry Anal Chem 81, 7288–7293.
Badjagbo, K., Héroux, M., Alaee, M., Moore, S., Sauvé, S., 2010 Quantitative analysis of
vol-atile methylsiloxanes in waste-to-energy landfill biogases using direct APCI–MS/MS.
Environ Sci Technol 44, 600–605.
Blanchard, O., Glorennec, P., Mercier, F., Bonvallot, N., Chevrier, C., Ramalho, O., Mandin, C.,
Bot, B.L., 2014 Semi-volatile organic compounds in indoor air and settled dust in 30
French dwelling Environ Sci Technol 48 (7), 3959–3969.
Bletsou, A.A., Asimakopoulos, A.G., Stasinakis, A.S., Thomaidis, N.S., Kannan, K., 2013 Mass
loading and fate of linear and cyclic siloxanes in a wastewater treatment plant in
Greece Environ Sci Technol 47, 1824–1832.
Brooke, D.N., Crookes, M.J., Gray, D., Robertson, D., 2009 Environmental Risk Assessment
Report: Decamethylcyclopentasiloxane Environmental Agency of England and
Wales, Bristol, UK, Britol.
Burns-Naas, L.A., Mast, R.W., Klykken, P.C., McCay, J.A., White, K.L., Mann, P.C., Naas, D.J.,
1998 Toxicology and humoral immunity assessment of decamethylcyclopentasiloxane
(D5) following a 1-month whole body inhalation exposure in Fischer 344 rats Toxicol.
Sci 43, 28–38.
CEPA (California Environmental Protection Agency), 1994 How much air do we breathe?
Brief report to the scientific and technical community Available: http://www.arb.ca.
gov/research/resnotes/notes/94-11.htm
Companioni-Damas, E.Y., Santos, E.J., Galceran, M.T., 2014 Linear and cyclic
methylsiloxanes in air by concurrent solvent recondensation-large volume
injec-tion–gas chromatography–mass spectrometry Talanta 118, 245–252.
Cortada, C., Reis, L.C., Vidal, L., Llorca, J., Canals, A., 2014 Determination of cyclic and linear
siloxanes in wastewater samples by ultrasound-assisted dispersive liquid–liquid
microextraction followed by gas chromatography–mass spectrometry Talanta 120,
191–197.
Environment Agency, German, 2011 Indoor air guide values for cyclic dimethylsiloxanes.
Bundesgesundheitsblatt 54, 388–400 http://dx.doi.org/10.1007/s00103-011-1218
Environment Canada, Health Canada, 2008 Screening Assessment for The, Challenge,
Decamethylcyclopentasiloxane (D5) available from:, http://ec.gc.ca/ese-ees/default.
asp?lang=En&n=13CC261E-5FB0-4D33-8000 (accessed Nov 2014).
He, B., Rhoders-Brower, S., Miller, M.R., Munson, A.E., Germolec, D.R., Walker, V.R., Korach,
K.S., Meade, B.J., 2003 Octamethylcyclotetrasiloxane exhibits estrogenic activity in
mice via Erα Toxicol Appl Pharmacol 192, 254–261.
Horii, Y., Kannan, K., 2008 Survey of organosiloxane compounds, including cyclic and
lin-ear siloxanes, in personal-care and household products Arch Environ Contam.
Toxicol 55, 701–710.
Jovanovic, M.L., McMahon, J.M., McNett, D.A., Tobin, J.M., Plotzke, K.P., 2008 In vitro and
in vivo percutaneous absorption of 14
C-octamethylcyclotetrasiloxane ( 14
C-D4) and
14
C-decamethylcyclopentasiloxane ( 14 C-D5) Regul Toxicol Pharmacol 50, 239–248.
Kaj, L., Schlabach, M., Andersson, J., Cousins, A.P., Schmidbauer, N., Brorstrom-Lunden, E.,
2005 Siloxanes in the Nordic Environment TemaNord, Nordic Council of Ministers, Copenhagen.
Kawamura, Y., Nakajima, A., Mutsuga, M., Yamada, T., Maitani, T., 2001 Residual chemical
in silicone rubber products for food contact use Shokuhin Eiseigaku Zasshi 42, 316–321 (Japanese).
Kierkegaard, A., McLachlan, M.S., 2010 Determination of decamethylcyclopentasiloxane
in air using commercial solid phase extraction cartridges J Chromatogr A 1217, 3557–3560.
Latimer, H.K., Kamens, R.M., Chandra, G., 1998 The atmospheric partitioning of decamethylcyclopentasiloxane (D5) and 1-hydroxynonamethylcyclopentasiloxane (D4TOH) on different types of atmospheric particles Chemosphere 36, 2401–2414.
Lee, S., Moon, H.B., Song, G.J., Ra, K., Kannan, K., 2014 A nationwide survey and emission estimates of cyclic and linear siloxanes through sludge from wastewater treatment plants in Korea Sci Total Environ 497–498, 106–112.
Lu, Y., Yuan, T., Yun, S.H., Wang, W., Wu, Q., Kannan, K., 2010 Occurrence of cyclic and lin-ear siloxanes in indoor dust from China, and implications for human exposures Envi-ron Sci Technol 44, 6081–6087.
McKim, J.M., Wilga, P.C., Breslin, W.J., Plotzke, K.P., Gallavan, R.H., Meeks, R.G., 2001 Po-tential estrogenic and antiestrogenic activity of the cyclic siloxane octamethyl-cyclotetrasiloxane (D4) and the linear siloxane hexamethylsiloxane (HMDS) in immature rats using the uterotrophic assay Toxicol Sci 63, 37–46.
Meeks, R.G., Stump, D.G., Siddiqui, W.H., Holson, J.F., Plotzke, K.P., Reynolds, V.L., 2007 An inhalation reproductive toxicity study of octamethylcyclotetrasiloxane (D 4 ) in female rats using multiple and single day exposure regimens Reprod Toxicol 23, 192–201.
Navea, J.G., Young, M.A., Xu, S.H., Grassian, V.H., Stanier, C.O., 2011 The atmospheric life-times and concentrations of cyclic methylsiloxanes octamethylcyclotetrasiloxanes (D4) and decamethylcyclopentasiloxane (D5) and the influence of heterogeneous uptake Atmos Environ 45, 3181–3191.
Ortega, R.D., Subrenat, A., 2009 Siloxane treatment by adsorption into porous materials Environ Technol 30 (10), 1073–1083.
Pieri, F., Katsoyiannis, A., Martellini, T., Hughes, D., Jones, K.C., Cincinelli, A., 2013 Occur-rence of linear and cyclic volatile methyl siloxanes in indoor air samples (UK and Italy) and their isotopic characterization Environ Int 59, 363–371.
Quinn, A.L., Dalu, A., Meeker, L.S., Jean, P.A., Meeks, R.G., Crissman, J.W., Gallavan, R.H., Plotzke, K.P., 2007a Effects of octamethylcyclotetrasiloxane (D 4 ) on the luteinizing hormone (LH) surge and levels of various reproductive hormones on female Sprague–Dawley rats Reprod Toxicol 23, 532–540.
Quinn, A.L., Regan, J.M., Tobin, J.M., Marinik, B.J., McMahon, J.M., McNett, D.A., Sushynski, C.M., Crofoot, S.D., Jean, P.A., Plotzke, K.P., 2007b In vitro and in vivo evaluation of the estrogenic, androgenic, and progestagenic potential of two cyclic siloxanes Toxicol Sci 96 (1), 145–153.
Sánchez-Brunete, C., Miguel, E., Albero, B., Tadeo, J.L., 2010 Determination of cyclic and linear siloxanes in soil samples by ultrasonic-assisted extraction and gas chromatog-raphy–mass spectrometry J Chromatogr A 1217, 7024–7030.
Shields, H.C., Fleischer, D.M., Weschler, C.J., 1996 Comparisons among VOCs measured in three types of US commercial buildings with different occupant densities Indoor Air Int J Indoor Air Qual Clim 6, 2–17.
U.S EPA (U.S Environmental Protection Agency), 2008 Child-Specific Exposure Factors Handbook (final report) Available: http://cfpub.epa.gov/ncea/cfm/recordisplay cfm?deid=199243
Utell, M.J., Gelein, R., Yu, C.P., Kenaga, C., Geigel, E., Torres, A., Chalupa, D., Gibb, F.R., Speers, D.M., Mast, R.W., Morrow, P.E., 1998 Quantitative exposure of humans to
an octamethylcyclotetrasiloxane (D4) vapor Toxicol Sci 44, 206–213.
Wang, X.M., Lee, S.C., Sheng, G.Y., Chan, L.Y., Fu, F.M., Li, X.D., Min, Y.S., Chan, C.Y., 2001.
Cyclic organosilicon compounds in ambient air in Guangzhou, Macau and Nanhai, Pearl River Delta Appl Geochem 16, 1447–1454.
Wang, R., Moody, R.P., Koniecki, D., Zhu, J., 2009 Low molecular weight cyclic volatile methylsiloxanes in cosmetic products sold on Canada: implication for dermal expo-sure Environ Int 35, 900–904.
Wang, D.G., Norwood, W., Alaee, M., Byer, J.D., Brimble, S., 2013a Review of recent ad-vances in research on the toxicity, detection, occurrence and fate of cyclic volatile methyl siloxanes in the environment Chemosphere 93, 711–725.
Wang, D.G., Steer, H., Tait, T., Williams, Z., Pacepavicius, G., Young, T., Ng, T., Smyth, S.A., Kinsman, L., Alaee, M., 2013b Concentration of cyclic volatile methylsiloxanes in bio-solid amended soil, influent, effluent, receiving water, and sediment of wastewater treatment plants in Canada Chemosphere 93, 766–773.
Warner, N.A., Evenset, A., Christensen, G., Gabrielsen, G.W., Borga, K., Leknes, H., 2010.
Volatile siloxanes in the European arctic: assessment of sources and spatial distribu-tion Environ Sci Technol 44, 7705–7710.
Yucuis, R.A., Stanier, C.O., Hornbuckle, K.C., 2013 Cyclic siloxanes in air, including identi-fication of high level in Chicago and distinct diurnal variation Chemosphere 92 (8), 905–910.
Zhang, Z., Qi, H., Ren, N., Li, Y., Gao, D., Kannan, K., 2011 Survey of cyclic and linear silox-anes in sediment from Songhua river and in sewage sludge from wastewater treat-ment plants, Northeastern China Arch Environ Contam Toxicol 60, 204–211.
144 T.M Tran, K Kannan / Science of the Total Environment 511 (2015) 138–144