Occurrence of benzotriazoles (BTRs) in indoor airfrom Albany, New York, USA, and its implicationsfor inhalation exposure

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Toxicological & Environmental Chemistry

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Occurrence of benzotriazoles (BTRs) in indoor air from Albany, New York, USA, and its implications for inhalation exposure

Jingchuan Xue, Yanjian Wan & Kurunthachalam Kannan

To cite this article: Jingchuan Xue, Yanjian Wan & Kurunthachalam Kannan (2017) Occurrence of benzotriazoles (BTRs) in indoor air from Albany, New York, USA, and its implications

for inhalation exposure, Toxicological & Environmental Chemistry, 99:3, 402-414, DOI:

10.1080/02772248.2016.1196208

To link to this article: http://dx.doi.org/10.1080/02772248.2016.1196208

Accepted author version posted online: 02 Jun 2016.

Published online: 22 Jun 2016.

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Occurrence of benzotriazoles (BTRs) in indoor air from Albany, New York, USA, and its implications for inhalation exposure

Jingchuan Xue^a, Yanjian Wan^band Kurunthachalam Kannan^a,c

aWadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Albany, NY, USA;^bCenter for Disease Control and Prevention of Yangtze River Administration and Navigational Affairs, General Hospital of the Yangtze River Shipping, Wuhan, China;^cBiochemistry Department, Faculty of Science and Experimental Biochemistry Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia

ARTICLE HISTORY Received 3 February 2016 Accepted 23 May 2016 ABSTRACT

Despite the widespread use of benzotriazoles as corrosion inhibitors in many household goods, studies on the occurrence of these compounds in indoor air are scarce. In this study,five benzotriazole derivatives were measured in 83 indoor air samples collected from various locations in Albany, New York, USA. Benzotriazoles were found in a majority of the indoor air samples, and the concentrations of their sum in bulk (vapor plus particulate phases) indoor air ranged from below the method limit of quantification to 492 ng¢m^¡3 (geometric mean: 5.8 ng¢m^¡3). The highest geometric mean concentration was found in air samples collected in parking garages (155 ng¢m^¡3), followed by barbershops (13.6), public places (11.5), auto repair shops (5.2), automobiles (4.5), homes (4.5), offices (3.7), and laboratories (2.8). Inhalation exposure to benzotriazoles was calculated on the basis of the measured geometric mean concentrations and air inhalation rate. The highest exposure dose was found for teenagers, with a geometric mean inhalation exposure dose of 79 ng¢day^¡1. The body-weight normalized exposure dose, however, was the highest for infants, at 3.2 ng¢(kg bw)^¡1¢day^¡1.

KEYWORDS

Benzotriazoles; corrosion inhibitor; indoor air;

inhalation exposure

Introduction

Benzotriazole (BTR) and its derivatives (collectively referred to as BTRs) are heterocyclic aromatic compounds that contain two fused rings. BTR is used as a restrainer in photo- graphic emulsions and is extensively used as a corrosion inhibitor in a broad range of con- sumer and industrial products, including antifreezes, circulating water in the heating and cooling systems, dishwasher detergents, automotive coolants, coating materials, hydraulic fluids, airplane deicing/anti-icing fluids, and hydraulic brake fluids (CDA 1970; Sease 1978; Wu et al.1998). BTRs have been in use for more thanfive decades and are catego- rized as“high production volume chemicals”by the United States Environmental Protec- tion Agency (EPA) (Hart et al.2004), with an estimated annual production rate of over 9,000 tons in the United States (Ferrey, Streets and Lueck 2013). Commonly known

CONTACT Kurunthachalam Kannan [email protected]

http://dx.doi.org/10.1080/02772248.2016.1196208

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derivatives of BTRs include 4-OH-BTR, 5-OH-BTR, tolyltriazole (TTR; a mixture of iso- mers of 4-Me-1H-BTR and 5-Me-1H-BTR), xylyltriazole (XTR; 5, 6-diMe-1H-BTR), and 5-Cl-BTR. XTR and TTR are also the major degradation products of BTR (Ferrey, Streets and Lueck2013). Occurrence and partial removal of BTRs in wastewater treatment plants have been reported (Asimakopoulos et al.2013a; Breedveld2002; Stasinakis2013). BTRs have been reported to be persistent in aquatic environments (Breedveld2002).

Studies have reported the occurrence of BTRs in various environmental and biological matrices, such as indoor dust (Wang et al.2013), wetland ecosystems (Matamoros, Jover and Bayona 2010) and human urine (Asimakopoulos et al. 2013b). However, little is known about the occurrence and proﬁles of BTRs in indoor air. In this study, 83 indoor air samples collected in 2014 from various locations in Albany, New York, USA, were analyzed to determine particulate and vapor phase concentrations of BTRs and to calculate inhalation exposure doses to these substances.

Materials and methods Standards and reagents

Analytical standard of 1H-benzotriazole (1H-BTR, 99%) was purchased from Alfa Aesar (Karlsruhe, Germany); 5-methyl-1H- benzotriazole (5-Me-1H-BTR, 98%) and 5, 6- dimethyl-1H-benzotriazole hydrate (5,6-diMe-1H-BTR, 99%) were purchased from Acros Organics (Morris Plains, NJ, USA); 4-hydroxy-benzotriazole hydrate (4-OH-BTR, 97%), 4-methyl-1H-benzotriazole (4-Me-1H-BTR, 90%), 5-chloro-benzotriazole (5-Cl-BTR, 99%), and d₄-BTR (100%) were purchased from Sigma-Aldrich (St. Louis, MO, USA);

and 5-hydroxy-benzotriazole hydrate (5-OH-BTR, >95%) was purchased from Leto- pharm (Shanghai, China). The molecular structures and select physicochemical properties of the target analytes are shown in Table S1. Stock solutions (1 g¢L^¡1) of each compound were prepared in methanol, stored at 20C until further use. Methanol (HPLC grade), and ethyl acetate (ACS grade) were purchased from Mallinckrodt Baker (Phillipsburg, NJ, USA). Milli-Q water was puriﬁed by an ultrapure water system (Barnstead International, Dubuque, IA, USA).

Sample collection

In total, 83 indoor air samples were collected from September to December 2014 at several locations in Albany, New York, USA. The sampling locations and the number of samples analyzed were as follows: parking garages (nD3), auto repair shops (nD4), automobiles (i.e., cars;nD7), barbershops (nD5), public places (e.g., malls;nD13), homes (nD26), laboratories (nD12), and offices (nD13). A low-volume air sampler (LP-20; A.P. Buck Inc., Orlando, FL, USA) was used to collect samples at a flow rate of 5 L¢min^¡1 for a period of between 3 and 24 h. The details of sample collection have been described elsewhere (Wan, Xue and Kannan 2015). Briefly, two polyurethane foam (PUF) plugs (ORBO-1000 PUF dimensions: 2.2 cm O.D£7.6 cm length) obtained from Supelco (Bellefonte, PA, USA) were used to collect the vapor phase; the particulate phase was collected simultaneously by a quartzfiberfilter (Whatman, grade QM-A, pore size: 2.2mm, 32 mm diameter). PUF plugs and glassfiberfilters were assembled in tandem, with thefil- ter on top of the PUF plugs. The newly purchased PUF plugs (nD3) were extracted twice

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with 100 mL of ethyl acetate and analyzed for the presence of background levels of target analytes. TTR was found in newly purchased PUF plugs at an average amount of 1.8 ng.

Therefore, all PUF plugs were washed twice by shaking with 100 mL of ethyl acetate for 30 min in a glass jar and kept in an oven at 100C until further use. The quartzfiberfilters were heated at 450C overnight and then held in an oven at 100C until further use. The mass of airborne particles was computed as the difference in the weights of quartzfiberfilters before and after sample collection.

Sample preparation

The details of the sample preparation have been described elsewhere (Wan, Xue and Kannan 2015). In brief, PUF plugs were extracted twice with 100 mL ethyl acetate each time for 30 min in an orbital shaker (Eberbach Corporation, Ann Arbor, MI, USA). The glass ﬁber ﬁlters were extracted with 20 mL ethyl acetate three times by shaking in an orbital shaker, each time for 5 min. Prior to extraction, 20 ng of d₄-BTR were spiked into all samples and procedural blanks. Extracts were combined and con- centrated in a rotary evaporator at 55 C to 5 mL. A gentle stream of nitrogen was used to further concentrate the solution to near dryness, and one mL of methanol was added and transferred into a vial for high performance liquid chromatography-tandem mass spectrometry analysis.

Instrumental analysis

Chromatographic separation was carried out using a Shimadzu Prominence Modular HPLC system (Shimadzu Corporation, Kyoto, Japan), consisting of a system controller, a binary pump and an automatic sampler. Identification and quantification of target analytes were performed with an Applied Biosystems API 3200 electrospray triple quadruple mass spectrometer (ESI-MS/MS; AB SCIEX, Framingham, MA, USA). A Betasil C18 column (2.1 mm£100 mm, 5mm; Thermo Fisher Scientific, Waltham, MA, USA) serially connected to a Javelin guard column (Betasil C18, 2.1 mm £ 20 mm, 5 mm; Thermo Fisher Scientific) was used. The injection volume was 10mL, and the mobile phase com- prised methanol (A) and Milli-Q water that contained 0.4% (v/v) acetic acid (B). The target compounds were separated by gradient elution at aflow rate of 300mL/min, starting at 10% (v/v) A, held for 0.5 min; increased to 40% A within 4.5 min; further increased to 99% A within 7 min, held for 6 min; and reverted to 10% A at the 18.5th min and held for 6.5 min, with a total run time of 25 min. The triple quadrupole mass spectrometer was operated in the multiple reaction monitoring (MRM) positive ionization mode. The MRM transitions were monitored (for quantitation and confirmation), and the compound specific MS/MS parameters are shown in Table S1. Nitrogen was used as both curtain and collision gas. The electrospray ionization voltage was set atC4.5 kV. The curtain and collision gasflow rates were set at 68947.5 and 27579.0 Pa, respectively. The source heater was set at 550 C. The nebulizer gas (ion source gas 1) was set at 310263.5 Pa, and the heater gas (ion source gas 2) was set at 482632.1 Pa. The data acquisition was performed at a scan speed of 37 ms and a resolving power of 0.70 full width at half maximum.

HPLC-MS/MS chromatograms of select analytes in calibration standard (2 ng¢mL^¡1 for analytes) and in quartzﬁberﬁlter and PUF samples are shown in Figure S1.

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Quality assurance and quality control

Quantification was performed by isotope dilution on the basis of responses of d4-BTR spiked into each sample. A 9- to 11-point standard calibration curve, with concentrations ranging from 0.1 to 200 ng¢mL^¡1, was used for the quantification of target analytes. The regression coefficients (r) were0.99 for all calibration curves. The limits of quantification (LOQs) were determined based on the lowest point of the calibration standard with a signal-to-noise ratio of>10. Method LOQs (MLOQs) were determined in a similar man- ner, with the post-extraction matrix-spiked calibration standards. MLOQs in the bulk air equaled the higher MLOQs obtained in either the vapor or the particulate phase. Chemi- cal concentrations in the bulk air were calculated by dividing the sum of the mass of the chemical in the vapor and particulate phases by the volume of air collected. A midpoint calibration standard was injected after every 10 samples, as a check for instrumental drift in response factors over time. Methanol was injected after every 10 samples as a check for carryover of target analytes between samples.

Several procedural blanks were analyzed with each batch of samples. To minimize background levels of target analytes, all glassware used for sampling and analysis was heated at 450 C for 10 h prior to use. Throughout the analysis, six sets of PUFs and quartzﬁberﬁlters were selected for pre-extraction matrix spike by spiking 40 ng of target analytes and passing them through the entire analytical procedure.

Data analysis

Data were acquired with Analyst software version 1.4.1 (Applied Biosystems). Statistical analyses were performed with statistics software package R v.3.1.0 and Microsoft Excel 2007. For the calculation of median, arithmetic mean (mean) and geometric mean (GM), concentrations below the MLOQ were substituted with a value equal to half the MLOQ.

Spearman correlation analysis was used to examine the correlations between datasets that did not follow a normal distribution. Only those samples with measurable concentrations were used in the correlation analysis. The Mann-WhitneyU test was used to assess the difference between means for datasets that did not follow a normal distribution. Normal- ity assumption was checked with a Shapiro-Wilk test and quantile-quantile plot. Statistical signiﬁcance was set atp<0.05. Daily exposure doses were calculated as

EDI_inhDC£AIR£IEF=BW; (1)

whereCis the concentration of analytes in bulk air (ng¢m^¡3), AIR is the air inhalation rate (m³¢day^¡1), IEF is the indoor exposure factor (the fraction of time spent indoors per day), and BW is the body weight (kg).

Method performance

The MLOQ of the target analytes ranged from 0.26 to 1.29 ng¢m^¡3in the vapor phase and from 1.43 to 35.7mg¢g^¡1in the particulate phase (Table S2). Trace levels of TTR (1.2 ng) were found in procedural blanks of the quartzﬁberﬁlter (Table S3). The concentrations found in procedural blanks were subtracted from the concentrations measured in samples.

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Absolute and relative recoveries were used in this study. Calculation of absolute recovery was based on the instrumental response of the analyte. The ratio of the signal for the analyte to that of the internal standard was used for the computation of relative recovery. In the vapor phase, relative recoveries of BTRs ranged from 65% to 110%, and in the particulate phase, these values were from 66% to 132%.

Results and discussion

Particulate phase concentrations of BTRs in indoor air

In the particulate phase, BTR and TTR were detected at (detection rate: DR) 100% and 75% of the samples analyzed, respectively (Table 1). The geometric mean (GM) concentration of BTR in the particulate phase was 13.6 mg¢g^¡1 and ranged from 2.35 to 395 mg¢g^¡1 (median: 12.8 mg¢g^¡1) (Table 1). The GM concentration of TTR was 9.15 mg¢g^¡1 and ranged from below MLOQ to 256 mg¢g^¡1 (median: 16.0 mg¢g^¡1) (Table 1). The highest concentration of BTR was found in ofﬁces (GM: 20.2 mg¢g^¡1, median: 24.8mg¢g^¡1), whereas the highest concentration of TTR was found in parking garages (GM: 19.2mg¢g^¡1, median: 21.9mg¢g^¡1) (Table 1). XTR, 4/5-OH-BTR, and 5-Cl- BTR were less frequently detected in the particulate phase, with DRs’ranging from 6.0%

to 8.4% (Table 1).

The concentrations of the sum of BTRs in the particulate phase ranged from 24.4 to 19400mg¢g^¡1(GM: 71.5mg¢g^¡1, median: 61.4mg¢g^¡1), and the highest concentration was found in parking garages (3570, 2010), followed by barbershops (162, 67), ofﬁces (67, 65), public places (66, 77), auto repair shops (62, 38), homes (57, 61), laboratories (50, 37), and automobiles (47, 31). The greater concentrations of BTRs in parking garages and barbershops were ascribed to high concentrations of XTR, one of the major degradation products of BTR, found in these locations (Ferrey et al.2013). The concentrations of XTR in the particulate phase in parking garage air ranged from 1160 to 19300mg¢g^¡1 (GM:

3540 mg¢g^¡1; median: 1980 mg¢g^¡1), which can be explained by the widespread use of BTR as an additive in automotive coolants, transformer oil, and lubricant oil (CDA1970).

XTR concentrations in the particulate phase of indoor air in barbershops ranged from below MLOQ to 2660 mg¢g^¡1 (GM: 106 mg¢g^¡1; median: 18 mg¢g^¡1), which may be explained by the use of BTR in cleaning solutions, such as dry-cleaning ﬂuids (CDA 1970). BTR also is used in paints, pigmented lacquers, and inks as well as in air condition- ing and heating systems (CDA 1970). Airborne particles are a major source of indoor dust, and, thus, BTR concentrations measured in airborne particles were compared with those reported for indoor dust. The median concentrations of BTRs in airborne particles of indoor air in homes (61mg¢g^¡1) measured in this study were three orders of magnitude higher than those reported in indoor dust (36 ng¢g^¡1) collected from homes in Albany, New York, USA (Wang et al.2013). A similar difference (between the particulate phase and indoor dust concentrations) also was observed in the concentrations of bisphenol F (BPF) measured in the same set of samples (Xue et al.2016). Differences in particle sizes between airborne particles (<100mm) and settled dust (up to 2 mm) may partly contrib- ute to this discrepancy; however, further studies are needed to address this pattern (Wan et al.2015).

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Table1.Concentrationsofbenzotriazolesinparticulatephase(mgg¡1 )andvaporphase(ngm¡3 )ofindoorairsamplescollectedfromvariouslocationsinAlbany,New York,USAin2014. VaporphaseParticulatephase LocationsXTRTTRBTR4/5-OH-BTRP (BTRs)XTRTTRBTR4/5-OH-BTR5-Cl-BTRP (BTRs) Parkinggarages (nD3)

Mean2.520.360.360.133.49748024.94.852.381.017510 GM1.380.30.240.132.75354019.24.432.250.943570 Median0.650.370.130.131.85198021.95.791.790.722010 Range<MLOQ-6.26<MLOQ-0.57<MLOQ-0.81<MLOQ-<MLOQ1.85-7.021160-193007.08-45.62.35-6.40<MLOQ-3.57<MLOQ-1.601170-19400 DR33%67%33%0100%100%100%100%33%33%100% Autorepair shops (nD4)

Mean0.650.592.030.133.5323.170.110.61.790.72106 GM0.650.361.720.133.1721.715.58.971.790.7262 Median0.650.441.650.133.0017.9119.051.790.7238.3 Range<MLOQ-<MLOQ<MLOQ-1.350.82-3.99<MLOQ-<MLOQ1.86-6.25<MLOQ-38.72.22-2565.00-19.5<MLOQ-<MLOQ<MLOQ-<MLOQ31.9-317 DR050%100%0100%25%100%100%00100% Automobiles (nD7)

Mean0.651.422.610.134.9317.923.616.21.791.0360.5 GM0.650.621.490.133.5217.95.5010.41.790.8847.0 Median0.651.362.070.134.4417.95.819.501.790.7230.6 Range<MLOQ-<MLOQ<MLOQ-5.110.40-8.26<MLOQ-<MLOQ1.44-14.3<MLOQ-<MLOQ<MLOQ-79.42.44-29.3<MLOQ-<MLOQ<MLOQ-2.926.2-135 DR057%100%0100%057%100%014%100% Barbershops (nD5)

Mean0.650.490.930.242.4471615.57.412.990.72743 GM0.650.470.710.182.371067.366.272.620.72162 Median0.650.400.860.132.5017.914.84.411.790.7267.1 Range<MLOQ-<MLOQ0.31-0.73<MLOQ-1.53<MLOQ-0.661.69-3.37<MLOQ-2660<MLOQ-40.93.5-13.5<MLOQ-6.00<MLOQ-<MLOQ25.5-2690 DR0100%80%20%100%40%80%100%40%0100% Publicplaces (nD13)

Mean0.652.84.971.6610.217.935.121.31.990.7276.9 GM0.651.474.070.258.8017.917.016.41.920.7265.9 Median0.652.354.390.1312.017.931.125.41.790.7276.9 Range<MLOQ-<MLOQ<MLOQ-6.531.68-9.31<MLOQ-11.83.05-16.4<MLOQ-<MLOQ<MLOQ-67.63.75-46.1<MLOQ-4.33<MLOQ-<MLOQ26.0-129 DR076.9%100%15.4%100%084.6%100%7.69%0100% Homes(nD26)

Mean0.651.182.20.194.3519.226.432.11.931.6581.3 GM0.650.461.260.143.2918.67.5614.31.870.8556.5 Median0.650.231.480.133.0217.911.613.11.790.7260.8 Range<MLOQ-<MLOQ<MLOQ-7.21<MLOQ-5.83<MLOQ-1.80<MLOQ-12.7<MLOQ-53.6<MLOQ-1862.71-395<MLOQ-5.30<MLOQ-24.124.4-601 DR050%92%3.9%92%3.9%69%100%3.9%7.7%100% Labs(nD12)

Mean0.650.491.310.132.7117.920.420.91.940.7261.9 GM0.650.330.740.132.3417.95.1115.81.900.7250.0 Median0.650.331.270.132.4217.93.5513.11.790.7237.0 Range<MLOQ-<MLOQ<MLOQ-1.35<MLOQ-3.23<MLOQ-<MLOQ<MLOQ-4.82<MLOQ-<MLOQ<MLOQ-92.76.13-52.2<MLOQ-3.57<MLOQ-<MLOQ28.0-165 DR058%67%067%067%100%8.3%0100% Ofﬁces(nD13)

Mean0.650.961.660.153.5517.935.429.41.950.9685.5 GM0.650.590.990.152.9417.912.620.21.900.8266.9 Median0.650.891.070.133.9617.920.024.81.790.7265.2 Range<MLOQ-<MLOQ<MLOQ-2.19<MLOQ-4.39<MLOQ-0.29<MLOQ-6.77<MLOQ-<MLOQ<MLOQ-1593.85-87.5<MLOQ-3.90<MLOQ-3.8024.9-137 DR069%85%15%85%077%100%7.7%7.7%100% Total(nD83)

Mean0.721.222.30.44.7733029.523.521.09386 GM0.670.551.260.153.5124.69.1513.61.920.7971.5 Median0.650.521.530.133.5517.916.012.81.790.7261.4 Range<MLOQ-6.26<MLOQ-7.21<MLOQ-9.31<MLOQ-11.8<MLOQ-16.4<MLOQ-19300<MLOQ-2562.35-395<MLOQ-6.00<MLOQ-24.124.4-19400 DR1.20%63%87%7.2%90%8.4%75%100%8.4%6.0%100% GM:geometricmean; DR:detectionrates; MLOQ:methodlimitofquantitation.

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Vapor phase and bulk air concentrations of BTRs in indoor air

BTR and TTR also were the predominant compounds found in the vapor phase, among the ﬁve BTRs measured, with the detection rates (DRs) of 87% and 63%, respectively (Table 1). The GM concentration of BTR in the vapor phase was 1.26 ng¢m^¡3and ranged from below MLOQ to 9.3 ng¢m^¡3(median: 1.5 ng¢m^¡3) (Table 1). The concentrations of TTR in the vapor phase ranged from below MLOQ to 7.2 ng¢m^¡3 (GM: 0.55 ng¢m^¡3, median: 0.52 ng¢m^¡3) (Table 1). In the vapor phase of indoor air, the highest concentrations of both BTR and TTR were found in public places (GM: 4.1 ng¢m^¡3, median:

4.4 ng¢m^¡3; GM: 1.5 ng¢m^¡3, median: 2.4 ng¢m^¡3, respectively) (Table 1). XTR and 4/5- OH-BTR were less frequently detected in the vapor phase (DR: 1.2% and 7.2%, respectively) (Table 1). 5-Cl-BTR was below the MLOQ in the vapor phase in all of the samples.

The concentrations of the sum of BTRs in the vapor phase ranged from below MLOQ to 16.4 ng¢m^¡3(GM: 3.5 ng¢m^¡3, median: 3.6 ng¢m^¡3), and the highest concentration was found in public places (8.8, 12), followed by automobiles (3.5, 4.4), homes (3.3, 3.0), auto repair shops (3.2, 3.0), ofﬁces (2.9, 4.0), parking garages (2.8, 1.9), barbershops (2.4, 2.5), and laboratories (2.3, 2.4).

In the bulk air, BTR was found in 98% of the samples and was the most frequently detected compound, followed by TTR (74 %), 4/5-OH-BTR (9.6%), XTR (8.4%), and 5- Cl-BTR (1.2%) (Table 2). The concentrations of BTR in the bulk air ranged from below MLOQ to 14.5 ng¢m^¡3 (GM: 1.9 ng¢m^¡3, median: 2.2 ng¢m^¡3) (Table 2). The GM concentrations of TTR in the bulk air was 0.95 ng¢m^¡3 (median: 1.5 ng¢m^¡3; range:

<MLOQ -10.0 ng¢m^¡3;Table 2). Parking garages contained the highest concentrations of the sum of BTRs in the bulk air (GM: 155 ng¢m^¡3, median: 107 ng¢m^¡3), followed by barbershops (14, 6.6), public places (12, 13.0), auto repair shops (5.2, 4.4), automobiles (4.5, 5.7), homes (4.5, 4.0), ofﬁces (3.7, 5.5), and laboratories (2.8, 2.7). The overall median concentration of BTRs in the bulk air of all samples collected in this study was 5.7 ng¢m^¡3. The total BTR concentrations were higher than those reported for bisphenols (BPs), bisphenol A diglycidyl ethers (BADGEs), benzophenone-3 (BP3), parabens, perﬂuor- oalkyl substances (PFASs), and polybrominated diphenyl ethers (PBDEs), but lower than those reported for benzothiazoles (BTHs), pesticides, alkylphenols, 4-tert-butylphenol, polychlorinated biphenyls (PCBs), siloxanes, and phthalates in the United States (Figure 1) (Fitzgerald et al.2011; Johnson-Restrepo and Kannan2009; Rudel et al.2003; Shoeib et al.

2004; Tran and Kannan2015a; Tran and Kannan2015b; Wan et al.2015; Wan et al.2016;

Xue et al.2016). In this study, the differences in the concentrations of BTRs between samples collected during the daytime and the nighttime in homes were examined. Although the GM concentrations of BTRs in samples collected during the daytime were slightly higher than those during the nighttime, the difference was not statistically signiﬁcant (Table S4).

The distribution of concentrations of BTRs between the vapor and particulate phases was examined by computing the ratio of the GM concentrations (after subtracting the cor- responding MLOQ values) of the analytes between the vapor phase and bulk air (Figure 2;

Table S5). With a ratio of 8%, XTR was found predominantly in the particulate phase (Table S5). The ratios of BTR and 4/5-OH-BTR were 65% and 67% (Figure 2; Table S5), respectively, which indicated preferential partitioning of these substances into the vapor phase. A ratio of 51% suggested an equal distribution for TTR between the two phases

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(Figure 2; Table S5). These observations can be supported by the logK_owvalues; logK_ow of XTR (2.26) is higher than that of TTR (1.71), BTR (1.17), and 4/5-OH-BTR (0.69) (Table S6). However, on the basis of models, 4/5-OH-BTR had the lowest values for vapor pressure and Henry’s law constant (Table S6). Further, the models for both XTR and TTR showed higher vapor pressure and Henry’s law constant than those for BTR, which suggested greater volatility of XTR and TTR (Table S6). Therefore, greater concentrations of 4/5-OH-BTR in the particulate phase were expected. XTR and TTR were expected to Table 2.Concentrations of benzotriazoles in bulk air (vapor plus particulate phases; ng m^¡³) samples collected from various locations in Albany, New York, USA in 2014.

Locations XTR TTR BTR 4/5-OH-BTR 5-Cl-BTR P

(BTRs) Parking

garages (nD3)

Mean 221 1.18 0.56 0.13 0.13 223

GM 152 1.11 0.48 0.13 0.13 155

Median 105 1.06 0.35 0.13 0.13 107

Range <MLOQ-490 0.74-1.73 0.31-1.03 <MLOQ-<MLOQ<MLOQ-<MLOQ 70.5-492

DR 100% 100% 100% 0 0 100%

Auto repair shops (nD4)

Mean 0.65 3.17 2.58 0.13 0.13 6.66

GM 0.65 1.46 2.31 0.13 0.13 5.21

Median 0.65 1.35 2.15 0.13 0.13 4.41

Range <MLOQ-<MLOQ 0.28-9.68 1.41-4.62 <MLOQ-<MLOQ<MLOQ-<MLOQ 2.6-15.2

DR 0 100% 100% 0 0 100%

Automobiles (nD7)

Mean 0.65 2.44 3.26 0.15 0.13 6.64

GM 0.65 0.9 1.97 0.15 0.13 4.53

Median 0.65 2.27 2.41 0.13 0.13 5.74

Range <MLOQ-<MLOQ<MLOQ-6.56 0.5-4.81 <MLOQ-0.28 <MLOQ-<MLOQ 1.62-17.0

DR 0 57% 100% 14% 0 100%

Barbershops (nD5)

Mean 50.7 1.21 1.46 0.24 0.13 53.8

GM 5.96 1.03 1.29 0.18 0.13 13.6

Median 3.05 1.2 1.86 0.13 0.13 6.61

Range <MLOQ-223 0.37-1.97 0.55-2 <MLOQ-0.66 <MLOQ-<MLOQ 3.14-228

DR 60% 100% 100% 20% 0 100%

Public places (nD13)

Mean 0.65 4.47 6.13 1.69 0.13 13.1

GM 0.65 2.52 5.14 0.27 0.13 11.5

Median 0.65 4.57 5.69 0.13 0.13 13.0

Range <MLOQ-<MLOQ<MLOQ-10.0 2.39-10.92 <MLOQ-12.1 <MLOQ-<MLOQ 4.96-21.5

DR 0 85% 100% 23% 0 100%

Homes (nD26)

Mean 0.68 2.06 3.19 0.19 0.16 6.29

GM 0.67 0.8 1.95 0.14 0.14 4.47

Median 0.65 1 2.41 0.13 0.13 3.95

Range <MLOQ-1.54 <MLOQ-8.35 0.46-14.5 <MLOQ-1.8 <MLOQ-0.92 1.5-21.6

DR 3.9% 62% 100% 3.85% 3.9% 100%

Labs (nD12)

Mean 0.65 0.79 1.67 0.13 0.13 3.37

GM 0.65 0.43 1.1 0.13 0.13 2.81

Median 0.65 0.42 1.44 0.13 0.13 2.73

Range <MLOQ-<MLOQ<MLOQ-2.19<MLOQ-3.87<MLOQ-<MLOQ<MLOQ-<MLOQ<MLOQ-6.4

DR 0 58% 92% 0 0 92%

Ofﬁces (nD13)

Mean 0.65 1.54 2.21 0.16 0.13 4.69

GM 0.65 0.89 1.43 0.15 0.13 3.73

Median 0.65 1.99 2.01 0.13 0.13 5.51

Range <MLOQ-<MLOQ<MLOQ-4.26<MLOQ-4.96 <MLOQ-0.38 <MLOQ-<MLOQ<MLOQ-9.19

DR 0 85% 92% 15% 0 92%

Total (nD83)

Mean 11.7 2.18 3.06 0.41 0.14 17.4

GM 0.91 0.95 1.86 0.16 0.13 5.77

Median 0.65 1.53 2.18 0.13 0.13 5.74

Range <MLOQ-490 <MLOQ-10.0<MLOQ-14.5 <MLOQ-12.1 <MLOQ-0.92 <MLOQ-492

DR 8.4% 74% 98% 9.6% 1.2% 98%

GM: geometric mean;

DR: detection rates;

MLOQ: method limit of quantitation.

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partition preferentially in the vapor phase relative to BTR. Further studies are warranted to understand the fate of these substances in indoor air.

The distribution of BTR and TTR between the vapor and particulate phases varied, depending on the locations (Figure 2; Table S5) and this could be attributed to sources of release and several other factors listed below. The vapor phase concentrations of BTR in auto repair shops, automobiles, public places, homes, laboratories, and offices were higher than those in the particulate phase (Figure 2). However, in parking garages, BTR concentrations were higher in the particulate phase than in the vapor phase (Figure 2). In barbershops, an equal distribution of BTR between the particulate and the vapor phases was observed (Figure 2). For TTR, higher concentrations in the vapor phase than in the particulate phase were observed in automobiles, public places, laboratories, and offices, whereas, Figure 1.Comparison of bulk indoor air organic contaminant concentrations in various locations from the United States.âMedian concentrations were used except for siloxanes and PCBs (for which mean concentrations were used).â(Tran and Kannan2015a)-siloxanes:five cyclic (D3-D7) and nine linear (L3- L11). (Rudel et al.2003)-phthalates: diethyl phthalate, di-n-butyl phthalate, bis(2-ethylhexyl) phthalate, bis(2-ethylhexyl) adipate, and diisobutyl phthalate; alkylphenols: 4-nonylphenol, nonylphenol monoethoxylate, and octylphenol monoethoxylate; parabens: methyl paraben; pesticides: a-chlordane, g-chlordane, pentachlorophenol, o-phenylphenol, o-phenyl phenol; 4-tert-butylphenol. (Tran and Kannan 2015b)-phthalates: dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, di-n-hexyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, di-n-octyl phthalate, di-n-butyl phthalate, di (2-ethylhexyl) phthalate. (Fitzgerald et al.2011)-PCBs: PCB-28, 74, 99, 105, 118, 138, 153/132, 170, 180, 183, 187, and 194. (Johnson-Restrepo and Kannan2009)-PBDEs’: PBDE-28, 47, 66, 77, 85, 99, 100, 118, 138, 153, 154, 183, 203, 207, and 209. (Shoeib et al.2004)-PBDEs: PBDE-17, 28/31, 47, 85, 99, 100, 153, 154, and 183; PFASs: MeFOSE, EtFOSE, and MeFOSEA. (Wan, Xue and Kannan2016)-BTHs: benzothiazole, 2-hydroxybenzothiazole, 2-aminobenzothiazole, and 2-methylthio-benzothiazole; (Wan, Xue and Kannan 2015)-BP3. (Xue, Wan and Kannan 2016)-BPs: BPA, BPF, BPS, BPAF, BPAP, BPP, BPZ, BPB;

BADGEs: BADGE, BADGE¢2H2O, BADGE¢H2O, BADGE¢2HCl, BADGE¢HCl, and BADGE¢HCl¢H2O.

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in parking garages, auto repair shops, and barbershops, higher concentrations were found in the particulate phase (Figure 2). The differences in the distribution of BTRs between the particulate and vapor phases among various locations can be explained by several factors, including sources of release, amount of particulate matter in air, and temperature, among others. The relationship between the concentrations of BTR and TTR in indoor air was examined, and a signiﬁcant positive relationship was observed (Figure 3). This may suggest their co-exposure or the degradation of BTR into TTR in the environment.

Figure 2.Distribution of BTR (top bars) and TTR (bottom bars) between the vapor and particulate phases of indoor air in various locations from Albany, New York, USA.

Figure 3.Relationship between BTR and TTR concentrations (ng m^¡³, sum of particulate and vapor phase concentrations) in indoor air from Albany, New York, USA. Only measurable values were used.

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Inhalation exposure to BTRs

According to the U.S. EPA’sExposure Factors Handbook (U.S. EPA2011), we grouped individuals into ﬁve categories, as infants (< 1 year), toddlers (1 3 years), children (4 11 years), teenagers/young adults (12 21 years), and adults (21 years), for exposure assessment. Inhalation exposure doses of BTRs were calculated on the basis of the GM concentrations of analytes in bulk air. The estimated daily inhalation exposure doses to XTR, TTR, BTR, and 4/5-OH-BTR are shown in Table S7. The inhalation exposure doses to BTR ranged from 8.1 ng¢day^¡1for infants to 25.6 ng¢day^¡1for teenagers/young adults, which contributed most to the total BTRs exposure dose, followed by TTR (4.2 ng¢day^¡1 for infants to 13 ng¢day^¡1 for teenagers/young adults) and XTR (4.0 to 12.5). The body weight normalized inhalation exposure doses to BTRs are shown in Table S8.

The estimated daily inhalation exposure doses of BTRs for infants, toddlers, children, teenagers/young adults, and adults were 25, 39, 57, 79 and 73 ng¢day^¡1, respectively (Table 3). The body-weight normalized exposure doses of BTRs for infants, toddlers, and children were 3.2, 3.1, and 2.1 ng¢(kg bw)^¡1¢day^¡1, respectively (Table 3). The location- speciﬁc exposure doses calculated for the sum of BTRs also are shown in Table 3. The highest exposure doses to adults were contributed in parking garages (GM: 1950 ng¢day^¡1), followed by barbershops (171), public places (144), auto repair shops (65), automobiles (57), homes (56), ofﬁces (47), and laboratories (35).

The daily intake of BTRs through indoor dust ingestion was reported to be 0.012 ng¢kg bw^¡1¢day^¡1 for U.S. adults (Wang et al. 2013), which was much lower than the inhalation exposure dose calculated for adults (0.70 ng¢kg bw^¡1¢day^¡1). Further, on the basis of the reported urinary BTRs concentrations, a total BTR exposure dose for U.S. adults was estimated to be 1.0 mg¢day^¡1, which is an order of magnitude higher than that reported from bulk indoor air in this study (73 ng¢day^¡1) (Asima- kopoulos et al. 2013b). Tap water was considered to be a major source of human exposure to BTRs (Carpinteiro et al. 2012; Janna et al. 2011). Dishwasher detergents contain BTR and TTR at levels of tens to hundreds of mg g^¡1. Traces of BTR and TTR residues were reported to be left on washed tableware (Janna et al. 2011).

In summary, this is theﬁrst study to report the concentrations of BTRs in bulk indoor air as well as to assess the inhalation exposure to these substances. In select locations, such as parking garages, inhalation exposure is a signiﬁcant source of BTR exposures in Table 3.Estimated daily intake (EDIinh, ng day^¡¹and ng (kg bw)^¡¹day^¡¹) of total BTRs through inhalation of indoor air, based on geometric mean concentrations.

Estimated daily intakes (EDIinh) Before adjusting for

body weight (ng day^¡1)

After adjusting for body weight (ng (kg bw) ¹day ¹) Locations Infants Toddlers Children Teenagers Adults Infants Toddlers Children Teenagers Adults

Parking garages 677 1040 1540 2130 1950 86.9 82.4 56.1 32.8 24.3

Auto repair shops 22.8 34.9 51.7 71.6 65.4 2.92 2.77 1.89 1.10 0.82

Automobiles 19.8 30.3 44.9 62.3 56.9 2.54 2.40 1.64 0.96 0.71

Barbershops 59.4 91.1 135 187 171 7.62 7.23 4.92 2.88 2.14

Public places 50.3 77.0 114 158 144 6.45 6.11 4.16 2.43 1.81

Homes 19.5 29.9 44.3 61.4 56.1 2.50 2.37 1.62 0.94 0.70

Labs 12.3 18.8 27.9 38.6 35.3 1.58 1.49 1.02 0.59 0.44

Ofﬁces 16.3 25.0 37.0 51.3 46.8 2.09 1.98 1.35 0.79 0.59

Total 25.2 38.6 57.2 79.3 72.5 3.23 3.06 2.09 1.22 0.91

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humans. The contribution of indoor air inhalation from homes, however, is approxi- mately 5% 10% of the total BTR exposures from various sources.

Disclosure statement

No potential conﬂict of interest was reported by the authors.

References

Asimakopoulos, A.G., A. Ajibola, K. Kannan, and N.S. Thomaidis. 2013a. “Occurrence and Removal Efﬁciencies of Benzotriazoles and Benzothiazoles in a Wastewater Treatment Plant in Greece.” Science of the Total Environment 452 453: 163 171. doi:10.1016/j.scitotenv.

2013.02.041.

Asimakopoulos, A.G., L. Wang, N.S. Thomaidis, and K. Kannan.2013b.“Benzotriazoles and Ben- zothiazoles in Human Urine from Several Countries: A Perspective on Occurrence, Biotransfor- mation, and Human Exposure.” Environment International 59: 274 281. doi:10.1016/j.

envint.2013.06.007.

Breedveld., G.D., R. Roseth, M. Sparrevik, T. Hartnik, and L.J. Hem.2002.“Persistence of the De- icing Additive Benzotriazole at an Abandoned Airport.”Water, Air, and Soil Pollution:Focus3:

91 101. doi:10.1023/A:1023961213839.

Carpinteiro, I., B. Abuin., M. Ramil., I. Rodriguez, and R. Cela.2012.“Simultaneous Determination of Benzotriazole and Benzothiazole Derivatives in Aqueous Matrices by Mixed-mode Solid Phase Extraction Followed by Liquid Chromatography-tandem Mass Spectrometry.”Analytical and Bioanalytical Chemistry402 (7): 2471 2478. doi:10.1007/s00216-012-5718-z.

CDA (Copper Development Association).1970.Benzotriazole: An Effective Corrosion Inhibitor for Coppor Alloys. New York, NY: Copper Development Association.http://www.copper.org/publi cations/pub_list/pdf/a1349.pdf.

Ferrey, M., S. Streets, and A. Lueck.2013.Pharmaceuticals and Personal Care Products in Minneso- ta’s Rivers and Streams. Saint Paul: Minnesota Pollution Control Agency.https://www.pca.state.

mn.us/sites/default/ﬁles/tdr-g1-17.pdf.

Fitzgerald, E.F., S. Shrestha, P.M. Palmer, L.R. Wilson, E.E. Belanger, M.I. Gomez, M.R. Cayo, and S. Hwang.2011.“Polychlorinated Biphenyls (PCBs) in Indoor Air and in Serum Among Older Residents of Upper Hudson River Communities.”Chemosphere85 (2): 225 231. doi:10.1016/j.

chemosphere.2011.06.027.

Hart, D.S., L.C. Davis, L.E. Erickson, and T.M. Callender.2004.“Sorption and Partitioning Parame- ters of Benzotriazole Compounds.” Microchemical Journal 77 (1): 9 17. doi:10.1016/j.

microc.2003.08.005.

Janna, H., M.D. Scrimshaw., R.J. Williams, J. Churchley, and J.P. Sumpter.2011.“From Dishwasher to Tap? Xenobiotic Substances Benzotriazole and Tolyltriazole in the Environment.”Environ- mental Science & Technology45 (9): 3858 3864. doi:10.1021/es103267g.

Johnson-Restrepo, B., and K. Kannan.2009.“An Assessment of Sources and Pathways of Human Exposure to Polybrominated Diphenyl Ethers in the United States.”Chemosphere76: 542 548.

doi:10.1016/j.chemosphere.2009.02.068.

Matamoros, V., E. Jover, and J.M. Bayona. 2010. “Occurrence and Fate of Benzothiazoles and Benzotriazoles in Constructed Wetlands.”Water Science and Technology: a Journal of the Inter- national Association on Water Pollution Research61 (1): 191 198. doi:10.2166/wst.2010.797.

Rudel, R.A., D.E. Camann, J.D. Spengler, L.R. Korn, and J.G. Brody.2003.“Phthalates, Alkylphe- nols, Pesticides, Polybrominated Diphenyl Ethers, and Other Endocrine-disrupting Compounds in Indoor Air and Dust.” Environmental Science & Technology 37 (20): 4543 4553.

doi:10.1021/es0264596.

Sease, C.1978. “Benzotriazole: A Review for Conservators.”Studies in Conservation 23: 76 85.

doi:10.2307/1505798.

(14)

Shoeib, M., T. Harner, M. Ikonomou, and K. Kannan.2004.“Indoor and Outdoor Air Concentra- tions and Phase Partitioning of Perﬂuoroalkyl Sulfonamides and Polybrominated Diphenyl Ethers.”Environmental Science & Technology38 (5): 1313 1320. doi:10.1021/es0305555.

Stasinakis, A.S., N.S. Thomaidis, O.S. Arvaniti, A.G. Asimakopoulos, V.G. Samaras, A. Ajibola, D.

Mamais, and T.D. Lekkas.2013.“Contribution of Primary and Secondary Treatment on the Removal of Benzothiazoles, Benzotriazoles, Endocrine Disruptors, Pharmaceuticals and Per- ﬂuorinated Compounds in a Sewage Treatment Plant.” Science of the Total Environment 463 464: 1067 1075. doi:10.1016/j.scitotenv.2013.06.087.

Tran, T.M., and K. Kannan.2015a.“Occurrence of Cyclic and Linear Siloxanes in Indoor Air from Albany, New York, USA, and Its Implications for Inhalation Exposure.” Science of the Total Environment511: 138 144. doi:10.1016/j.scitotenv.2014.12.022.

Tran, T.M., and K. Kannan.2015b.“Occurrence of Phthalate Diesters in Particulate and Vapor Phases in Indoor Air and Implications for Human Exposure in Albany, New York, USA.”

Archives of Environmental Contamination and Toxicology68 (3): 489 499. doi:10.1007/s00244- 015-0140-0.

U.S. EPA.2011.Exposure Factors Handbook 2011 Edition (Final). Washington, DC: U.S. Environ- mental Protection Agency, EPA/600/R-09/052F. https://cfpub.epa.gov/ncea/risk/recordisplay.

cfm?deidD236252.

Wan, Y., J. Xue, and K. Kannan.2015.“Occurrence of Benzophenone-3 in Indoor Air from Albany, New York, USA, and Its Implications for Inhalation Exposure.”Science of the Total Environment 537: 304 308. doi:10.1016/j.scitotenv.2015.08.020.

Wan, Y., J. Xue, and K. Kannan.2016.“Occurrence of Benzothiazoles in Indoor Air from Albany, New York, USA, and Its Implications for Inhalation Exposure.”Journal of Hazarous Material 311: 37 42. doi:10.1016/j.jhazmat.2016.02.057.

Wang, L., A.G. Asimakopoulos, H.B. Moon, H. Nakata, and K. Kannan. 2013. “Benzotriazole, Benzothiazole, and Benzophenone Compounds in Indoor Dust from the United States and East Asian Countries.” Environmental Science & Technology 47 (9): 4752 4759. doi:10.1021/

es305000d.

Wu, X., N. Chou, D. Lupher, and L.C. Davis.1998.“Benzotriazoles: Toxicity and Degradation.”In Proceedings of the 1998 Conference on Hazardous Waste Research, 374 382.https://www.engg.

ksu.edu/HSRC/98Proceed/32Wu/32wu.pdf.

Xue, J., Y. Wan, and K. Kannan.2016.“Occurrence of Bisphenols, Bisphenol A Diglycidyl Ethers (BADGEs) and Novolac Glycidyl Ethers (NOGEs) in Indoor Air from Albany, New York, USA, and the Implications for Inhalation Exposure.” Chemosphere 151: 1 8. doi:10.1016/j.

chemosphere.2016.02.038.