Environment International 83 (2015) 183–191 Contents lists available at ScienceDirect Environment International journal homepage: www.elsevier.com/locate/envint Full length article A comparative assessment of human exposure to tetrabromobisphenol A and eight bisphenols including bisphenol A via indoor dust ingestion in twelve countries Wei Wang a, Khalid O Abualnaja b, Alexandros G Asimakopoulos a, Adrian Covaci c, Bondi Gevao d, Boris Johnson-Restrepo e, Taha A Kumosani b, Govindan Malarvannan c, Tu Binh Minh f, Hyo-Bang Moon g, Haruhiko Nakata h, Ravindra K Sinha i, Kurunthachalam Kannan a,b,⁎ 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 Biochemistry Department, Faculty of Science, Experimental Biochemistry Unit, King Fahd Medical Research Center, Bioactive Natural Products Research Group, King Abdulaziz University, Jeddah, Saudi Arabia c Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium d Environmental Management Program, Environment and Life Sciences Center, Kuwait Institute for Scientific Research, P.O Box 24885, Safat, 13109, Kuwait e Environmental and Chemistry Group, Sede San Pablo, University of Cartagena, Cartagena, Bolívar 130015, Colombia f Faculty of Chemistry, Hanoi University of Science, Vietnam National University, Hanoi, 19 Le Thanh Tong, Hoan Kiem, Hanoi, Viet Nam g Department of Marine Sciences and Convergent Technology, College of Science and Technology, Hanyang University, Ansan, South Korea h Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan i Department of Zoology, Patna University, Patna 800 005, India a r t i c l e i n f o Article history: Received 20 April 2015 Received in revised form 22 June 2015 Accepted 25 June 2015 Available online xxxx Keywords: TBBPA BPA Human exposure Indoor dust Microenvironment a b s t r a c t Tetrabromobisphenol A (TBBPA) and eight bisphenol analogues (BPs) including bisphenol A (BPA) were determined in 388 indoor (including homes and microenvironments) dust samples collected from 12 countries (China, Colombia, Greece, India, Japan, Kuwait, Pakistan, Romania, Saudi Arabia, South Korea, U.S., and Vietnam) The concentrations of TBBPA and sum of eight bisphenols (ƩBPs) in dust samples ranged from b1 to 3600 and from 13 to 110,000 ng/g, respectively The highest TBBPA concentrations in house dust were found in samples from Japan (median: 140 ng/g), followed by South Korea (84 ng/g) and China (23 ng/g) The highest ∑BPs concentrations were found in Greece (median: 3900 ng/g), Japan (2600 ng/g) and the U.S (2200 ng/g) Significant variations in BPA concentrations were found in dust samples collected from various microenvironments in offices and homes Concentrations of TBBPA in house dust were significantly correlated with BPA and ∑BPs Among the nine target chemicals analyzed, BPA was the predominant compound in dust from all countries The proportion of TBBPA in sum concentrations of nine phenolic compounds analyzed in this study was the highest in dust samples from China (27%) and the lowest in Greece (0.41%) The median estimated daily intake (EDI) of ∑BPs through dust ingestion was the highest in Greece (1.6–17 ng/kg bw/day), Japan (1.3–16) and the U.S (0.89–9.6) for various age groups Nevertheless, in comparison with the reported BPA exposure doses through diet, dust ingestion accounted for less than 10% of the total exposure doses in China and the U.S For TBBPA, the EDI for infants and toddlers ranged from 0.01 to 3.4 ng/kg bw/day, and dust ingestion is an important pathway for exposure accounting for 3.8–35% (median) of exposure doses in China © 2015 Elsevier Ltd All rights reserved Introduction Chemical concentrations in residential dust have been used as surrogates for indoor chemical exposures in many studies (Whitehead et al., 2011; Wang et al., 2013a; Ma et al., 2014) Indoor dust is a source of human exposure to pesticides, polychlorinated biphenyls (PCBs), ⁎ Corresponding author at: Wadsworth Center, Empire State Plaza, P.O Box 509, Albany, NY 12201-0509, United States E-mail address: Kurunthachalam.kannan@health.ny.gov (K Kannan) http://dx.doi.org/10.1016/j.envint.2015.06.015 0160-4120/© 2015 Elsevier Ltd All rights reserved polybrominated diphenyl ethers (PBDEs), phthalates, and bisphenols (BPs) (Liao et al., 2012a; Besis and Samara, 2012; Wang et al., 2013b, 2013c, 2013d) Indoor dust is an important source of human exposure to brominated flame retardant (BFR) such as PBDEs in North America (Besis and Samara, 2012) Tetrabromobisphenol A (TBBPA) is the largest production volume BFR, with an annual global production of more than 170,000 t in 2004 and is applied as a reactive or additive FR in polymers, resins, adhesives, and in the manufacture of printed circuit boards and electric equipment (ECB, 2006; Ni and Zeng, 2013) TBBPA released from these products 184 W Wang et al / Environment International 83 (2015) 183–191 can adhere to suspended particulate matter, due to its low vapor pressure (6.24 × 10−6 Pa) and high affinity for organic surfaces (log Kow: 7.20) (European Union, 2006) TBBPA has been reported to occur in indoor dust from Belgium (0.85–1480 ng/g), Japan (490–520 ng/g), and the UK (b 1–382 ng/g) (Geens et al., 2009; Takigami et al., 2009; Abdallah et al., 2008); Little is known on the occurrence of TBBPA in indoor dust from other countries and on the relationship of TBBPA with other bisphenols including BPA (Ma et al., 2014) With the structural resemblance to the thyroid hormone, thyroxin, TBBPA can bind to human transthyretin and disrupt thyroid hormone functions (Covaci et al., 2009) TBBPA's potential as an endocrine disruptor (EDC) is of concern and several studies have indicated the thyroid hormone-like and estrogen receptor-mediated effects of this compound (Kitamura et al., 2002; Ghisari and Bonefeld-Jorgensen, 2005; Grasselli et al., 2014) TBBPA was reported as a reproductive toxicant (Van der Ven et al., 2008) Additionally, immunotoxicity, neurotoxicity and interference of cellular signal pathways have been reported for TBBPA (Mariussen and Fonnuma, 2003; Pullen et al., 2003; Strack et al., 2007) In a recent study, TBBPA-mediated uterine cancer has been shown in rodents exposed under laboratory conditions (Dunnick et al., 2015) Bisphenols (BPs) are a group of chemicals with two hydroxyphenyl functionalities and are used as additives and/or reactive raw materials in polycarbonate plastics, plastic linings for food containers, dental sealants, and thermo-sensitive coatings for paper products among others (Song et al., 2014) Among BPs, BPA is widely used in numerous commercial applications and has been produced at over 3,600,000 t annually worldwide (Liao et al., 2012b) Human exposure to BPA is of concern because animal and human studies have identified potential health effects (Liao et al., 2012a; Song et al., 2014) The Canadian Government, the European Union and the U.S Food and Drug Administration (FDA) have prohibited BPA-based baby bottles/packaging in 2010, 2011 and 2012, respectively (Government of Canada, 2010; The European Commission, 2011; FDA, 2012) Owing to adverse health effects associated with exposure to BPA and other BPs, including bisphenol S (BPS, 4,4′sulfonyldiphenol) and bisphenol F (BPF, 4,4′-dihydroxydiphenylmethane), these chemicals are under scrutiny by various global health organizations (Zhou et al., 2014; Liao et al., 2012c) Although diet is an important source of human exposure to contaminants such as PCBs and BPA, indoor dust contributes to a considerable proportion of exposure to certain contaminants, especially in toddlers (Liao et al., 2012a; Besis and Samara, 2012; Wang et al., 2013d) Contribution of dust to TBBPA exposure in humans is not well known In light of the above gaps in knowledge, this study was conducted to (1) report the occurrence and profiles of TBBPA and BPs in indoor dust (home and other microenvironments) collected from 12 countries, and (2) estimate human exposure to TBBPA and BPs via dust ingestion opportunistic sampling is not expected to be representative of the country, but it can obtain a sufficient sample size in the variety of different types of sites (homes, offices, cars, etc.) desired for the study Floor dust samples were obtained from vacuum cleaner bags in each of the sampling sites following the same sampling protocol, with the exception of samples from China and India, which were obtained by sweeping the floor Only bedrooms and living rooms of homes and apartments (all countries) were selected for sampling All samples were transported to the laboratory at Wadsworth Center, sieved through a 150 μm sieve to represent the indoor settled dust, homogenized, packed in clean aluminum foil, and stored at °C until analysis Materials and methods 2.4 Instrumental analysis 2.1 Sample collection The concentrations of BPs were determined with a Shimadzu Prominence LC-20 AD HPLC (Shimadzu, Kyoto, Japan) interfaced with an Applied Biosystems API 3200 electrospray triple quadrupole mass spectrometer (ESI-MS/MS; Applied Biosystems, Foster City, CA) An analytical column (Betasilđ C18, 100 ì 2.1 mm column; Thermo Electron Corporation, Waltham, MA), connected to a Javelin guard column (Betasil® C18, 20 × 2.1 mm) was used for LC separation TBBPA was determined with an Agilent 1260 HPLC (Agilent Technologies Inc., Santa Clara, CA) interfaced with an Applied Biosystems QTRAP 4500 mass spectrometer (ESI-MS/MS; Applied Biosystems, Foster City, CA) An analytical column (Ultra Biphenyl USP L11 μm, 100 × 2.1 mm column; Restek Corporation, Bellefonte, PA), connected to a Javelin guard column (Betasilđ C18, 20 ì 2.1 mm), was used for LC separation The negative ion multiple reaction monitoring (MRM) mode was used The MS/MS parameters were optimized by infusion of individual compounds into the MS through a flow injection system (Table S2) The In total, 388 indoor dust samples were collected from 12 countries, with 284 samples from homes and 104 from other microenvironments (laboratories, offices, cars, air conditioner, and e-waste workshop) (Table S1; Supporting Information) House dust samples (5–50 g) were collected from select cities in China (CN, number of samples: n = 34), U.S (US, 22), India (IN, 35), Japan (JP, 14), Greece (GR, 28), Colombia (CO, 42), Pakistan (PK, 22), Saudi Arabia (SA, 19), South Korea (KR, 16), Kuwait (KW, 17), Romania (RO, 23), and Vietnam (VN, 12) from 2012 to 2014 Dust samples from laboratories, offices, cars, and public areas were collected from South Korea (lab, n = 11; office, 14), Kuwait (car, 15), Pakistan (car, 6; office 24), Saudi Arabia (air conditioners in homes, 12; car, 10), and Vietnam (e-waste work shop, 4; public area, 8) We employed volunteers to collect samples in each country, and these volunteers sampled sites for which they had access This approach of 2.2 Chemicals and reagents BPA, BPS, BPF, bisphenol Z (BPZ), bisphenol AP (BPAP), and bisphenol AF (BPAF) were obtained from Sigma-Aldrich (St Louis, MO) Bisphenol B (BPB) and TBBPA were purchased from TCI America (Portland, OR) and BOC Sciences (Shirley, NY), respectively Mass-labeled 13C-BPA (RING-13C12, 99%) and 13C-TBBPA (RING-13C12, 99%) were obtained from Cambridge Isotope Laboratories (Andover, MA) and Wellington Laboratories (Guelph, Ontario, Canada), respectively HPLC grade methanol and tetrahydrofuran were supplied by J.T Baker (Phillipsburg, NJ) Ultra-pure water (18.2 Ω) was generated using a Milli-Q system (Millipore, Billerica, MA) Sep-Pak® C18 (1 g, mL) solid-phase extraction cartridges were obtained from Waters (Milford, MA) 2.3 Sample preparation Dust samples were extracted and analyzed by following the method described elsewhere (Liao et al., 2012a; Song et al., 2014), with some modifications Briefly, 0.1 g of sample was weighed and transferred into a 15 mL polypropylene (PP) conical tube After spiking with 20 ng 13 C12-BPA and 13C12-TBBPA (internal standards, IS), sample was extracted with a mL solvent mixture of methanol and water (5:3, v/v) by shaking for 60 The mixture was centrifuged at 4500 g for (Eppendorf Centrifuge 5804, Hamburg, Germany), and the supernatant was transferred into a glass tube The extraction step was repeated three times with same amount of solvent, and the extracts were combined and concentrated to ∼4 mL under a gentle nitrogen stream The solution was diluted to 10 mL with 0.2% formic acid (pH 2.5), and the extracts were loaded onto a Sep-Pak C18 cartridge preconditioned with mL of methanol and mL of water After loading, the cartridge was washed with mL of water and the analytes were eluted with mL of methanol, mL of tetrahydrofuran/methanol (4:6) and mL of tetrahydrofuran, and finally concentrated to mL prior to high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis W Wang et al / Environment International 83 (2015) 183–191 MRM transitions of ions monitored are listed in Table S3 Nitrogen was used as both a curtain and a collision gas 2.5 Quality assurance and quality control (QA/QC) With each set of 20 samples analyzed, a procedural blank, a spiked blank (containing water instead of dust), a pair of matrix spike samples (20 ng), and duplicate samples were analyzed Trace levels of BPA and BPF (approximately 0.25 and 0.34 ng/g, respectively) were found in procedural blanks, and background subtraction was performed for these compounds in the quantification of concentrations Recoveries of BPs in spiked matrices ranged from 78.3 ± 24.0% for BPB to 105 ± 29.5% for BPAF (Table S3) Duplicate analysis of randomly selected samples showed a coefficient variation of b 20% for BPs and TBBPA The limits of quantification (LOQs) were 0.1 ng/g for BPAF, 0.5 ng/g for BPA, BPAP and BPZ, ng/g for BPF, BPB and TBBPA, and 2.0 ng/g for BPS and BPP (Table S3), which were calculated from the lowest acceptable calibration standard and a nominal sample weight of 0.1 g A midpoint calibration standard (in methanol) was injected as a check for instrumental drift in sensitivity after every 20 samples, and a pure solvent (methanol) was injected as a check for carry-over from sample to sample Instrumental calibration was verified by injection of 10 calibration standards (ranging from 0.02 to 100 ng/g), and the linearity of the calibration curve (r) was N 0.99 Concentrations of TBBPA and BPs in the fourth extraction with a mixture of methanol and water (5:3, v/v) for 15 randomly selected dust samples were b1% of the concentrations found in the first three extractions, which indicated that the three extraction cycles completely extracted the target chemicals For ease of discussion and exposure assessment, dust from homes and other microenvironments were segregated 2.6 Calculation of exposure doses The median and 95th percentile concentrations of the target analytes measured in home dust were applied for the estimation of median and high scenarios for daily intakes (EDI; ng/kg bw/day), respectively, through dust ingestion, as shown in Eq (1) EDI ẳ C DIR BW 1ị where C is the TBBPA/BPs concentration in measured house dust (ng/g), DIR is the dust ingestion rate (g/day), and BW is the body weight (kg) In this study, only a limited number of samples were analyzed from offices, cars and other public places Therefore, only residential dust exposures were taken into account, with median and high exposure profiles, based on the median and the 95th percentile concentrations of the contaminants in house dust The dust intake rate was applied as 0.03, 0.06, 0.06, 0.06, 0.03 g/d for infants (b1 year), toddlers (1–5 year), children (6–10 year), teenagers (11–20 year) and adults (N20 year), respectively, by following the data reported elsewhere (US EPA, 2011) The respective average body weights for infants, toddlers, children, teenagers and adults in Asian countries were 5, 19, 29, 53, and 63 kg, as reported for China (Guo and Kannan, 2011; Liao et al., 2012a), while the values for U.S., Colombia, and European countries were 7, 15, 32, 64, and 80 kg as reported for the U.S (US EPA, 2011) Considering the low concentrations of other bisphenol analogues, such as BPB, only the exposure doses for BPA, BPS, BPF, ∑BPs and TBBPA were calculated in this study Details of the parameters used in EDI calculation are shown in Table S4 2.7 Statistical analysis Statistical analyses were performed with Origin ver (for profile analyses and box plot) and SPSS 16.0 software (for correlation analyses, test for normality and ANOVA) Normality of the data was checked by Shapiro–Wilk test The 95% upper confidence limit (UCL) was calculated 185 using ProUCL 4.0 Concentrations below the LOQ were substituted with a value equal to LOQ divided by the square root of for the calculation of geometric mean (GM) Differences between groups were compared using a one-way ANOVA followed by a Tukey test Prior to one-way ANOVA, the data were log-transformed to meet the normality assumptions Spearman correlation was used to investigate the relationship between BPs and TBBPA concentrations The probability value of p ≤ 0.05 was set for statistical significance Results and discussion 3.1 TBBPA in house dust In spite of the limited sample size for individual countries, this study describes the widespread occurrence of TBBPA in indoor dust TBBPA was found in 80% of house dust samples at a concentration that ranged from b1 to 2300 ng/g (Table 1) High concentrations of TBBPA were found in house dust from Japan (range: 12–1400 ng/g), South Korea (43–370 ng/g) and China (b1–2300 ng/g) and the concentrations found in these three countries were 10 to 100 times higher than the concentrations found in the other countries studied Relatively lower concentrations of TBBPA were found in dust from Colombia (b 1–280 ng/g), Romania (b1–380), Kuwait (b 1–36) and Greece (b 1–630) In 2001, the highest TBBPA consumption was registered in Asia (89,400 t/year) (Covaci et al., 2009) Considering the high market demand for this flame retardant in eastern Asian countries, high concentrations of TBBPA found in dust from Japan, South Korea, and China can be related to the emission from commercial products The median concentrations of TBBPA in house dust were in the following decreasing order: Japan (140 ng/g) N South Korea (84) N China (23) N the U.S (20) N Saudi Arabia (18) N Greece (11) N India (9.0) N Kuwait (8.4) N Pakistan (7.2) N Romania (6.0) N Colombia (3.3) N Vietnam (1.6) (Fig 1) In comparison with the reported median concentrations of PBDEs in indoor dust from China (median: 739–1940 ng/g) (Kang et al., 2011), the U.S (1910–21,000) (Johnson-Restrepo and Kannan, 2009; Batterman et al., 2009), Kuwait (90) (Gevao et al., 2006) and Japan (485–700) (Suzuki et al., 2006; Takigami et al., 2009), TBBPA concentrations were significantly (one to three orders of magnitude) lower, possibly attributing to the limited proportion (20–30%) of this compound applied as an additive BFR in products However, TBBPA concentrations as high as 2300 ng/g were found in dust from Chinese homes 3.2 BPs in house dust BPA was found in all house dust samples at concentrations that ranged from 9.6 to 32,000 ng/g, with a global median concentration of 440 ng/g, which was 10 to 100 times higher than that of TBBPA concentration The highest BPA concentration was found in dust from Japan (median: 1700 ng/g), followed by Greece (1500), the U.S (1500) and South Korea (720) (Fig 1) Besides BPA, BPS and BPF were also found widely in dust samples, collectively accounting for, on average, 45% of ∑BPs concentrations This profile was similar to those reported previously for indoor dust from the U.S., Japan, South Korea and China (Liao et al., 2012a) High concentrations of BPF found in dust from South Korea (median: 1000 ng/g), Greece (780), Japan (230), and the U.S (200) indicated high usage of this BP analogue in these countries BPF has been reported as a major alternative to BPA in industrial applications in South Korea (Lee et al., 2015) BPP (detection frequency: 0.34%), BPAF (73%), and BPAP (0.68%) were also found in some dust samples, but their concentrations were very low The concentrations of ∑BPs in house dust from the 12 countries investigated, were in the following decreasing order: Greece (range 510–110,000; median 3900 ng/g), Japan (360–12,000; 2600), the U.S (550–89,000; 2200), South Korea (540–6100, 1600), Saudi Arabia (130–3200, 1200), Romania (37–6000, 870), Vietnam (66–1600, 400), Kuwait (61–1400, 380), China (43–4400, 350), India (40–6200, 180), Colombia (42–2300, 180) and Pakistan (23–860, 150) 186 W Wang et al / Environment International 83 (2015) 183–191 Table TBBPA and BP concentrations in house dust (ng/g) from 12 countries China n = 34 Colombia n = 42 Greece n = 28 India n = 35 Japan n = 14 South Korea n = 16 Kuwait n = 17 Pakistan n = 22 Romania n = 23 Saudi Arabia n = 19 U.S n = 22 Vietnam n = 12 Total n = 284 a Mean Median Min Max DRa% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% Mean Median Min Max DR% BPF BPA BPB BPS BPZ BPAP BPAF BPP ∑BPs TBBPA 1.9 b1 b1 13 53 69 33 b1 780 90 5500 780 b1 110,000 82 29 6.7 b1 290 77 650 230 b1 2900 93 1300 1000 13 3600 100 78 22 b1 390 89 56 50 5.6 140 100 41 2.0 b1 340 61 160 73 5.5 1500 100 4400 200 39 89,000 100 200 57 b1 1500 92 1000 36 b1 110,000 83 670 330 37 4400 100 420 120 9.6 2000 100 1700 1500 27 4400 100 360 130 20 6200 100 2800 1700 250 10,000 100 1100 720 270 3600 100 390 250 39 1200 100 100 66 9.7 710 100 680 600 18 1700 100 1100 650 110 3200 100 3800 1500 260 32,000 100 330 230 27 1400 100 1000 440 9.6 32,000 100 b1 b1 b1 4.6 b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – b1 b1 b1 b1 – 1.1 b1 b1 8.4 b1 b1 b1 b1 – b1 b1 b1 8.4 b2 b2 b2 b2 – 3.7 2.4 b2 35 62 1500 860 b2 21,000 86 12 4.2 b2 150 60 440 160 8.8 1800 100 8.8 3.6 b2 32 50 38 20 b2 200 68 10 1.8 b2 66 50 380 82 6.2 4900 100 110 28 b2 1100 63 2.1 b2 b2 12 18 28 b2 b2 260 33 220 3.2 b2 21,000 100 b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – b0.5 b0.5 b0.5 b0.5 – 0.5 b0.5 b0.5 3.4 0.7 b0.5 b0.5 4.5 0.38 b0.5 b0.5 4.5 4.4 1.9 0.8 54 100 4.3 2.2 0.07 34 98 4.6 2.5 b0.1 47 79 1.7 1.5 b0.1 6.5 83 4.8 4.1 0.88 14 100 2.6 3.0 b0.1 5.6 94 3.2 2.5 0.38 13 100 1.3 1.3 b0.1 2.9 77 0.88 0.39 b0.1 5.2 74 2.5 2.2 b0.1 6.7 89 4.7 1.4 0.23 25 100 1.3 1.1 b0.1 2.9 92 3.1 1.8 b0.1 54 73 b2 b2 b2 9.4 b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 b2 – b2 b2 b2 9.4 – 690 350 43 4400 100 500 180 42 2300 100 8800 3900 510 110,000 100 410 180 40 6200 100 3900 2600 360 12,000 100 2400 1600 540 6100 100 520 380 61 1400 100 170 150 23 860 100 1100 870 37 6000 100 1400 1200 130 3200 100 8300 2200 550 89,000 100 560 400 66 1600 100 2200 610 23 110,000 100 250 23 b1 2300 79 21 3.3 b1 280 76 36 11 b1 630 68 45 9.0 b1 640 86 360 140 12 1400 100 130 84 43 370 100 12 8.4 b1 36 89 50 7.2 b1 800 77 28 6.0 b1 380 81 61 18 b1 360 84 91 20 b1 650 77 99 1.6 b1 670 50 87 9.5 b1 2300 80 DR = detection rate 3.3 TBBPA and BPA in various microenvironments and comparison of results with other studies The concentrations and profiles of TBBPA and BPs in dust from various microenvironments are shown in Table S5 and Fig 2, respectively The concentrations of TBBPA in dust from laboratories and offices from South Korea (65–660 ng/g) were significantly (p b 0.05) higher than those in homes (43–370 ng/g) Similarly, significantly (p b 0.05) higher BPA concentrations were found in dust from offices (510– 6600 ng/g) and laboratories (980–27,000 ng/g) than homes W Wang et al / Environment International 83 (2015) 183–191 187 Fig Worldwide distribution of TBBPA and BPA (median values) in house dust from 12 countries Fig Comparison of TBBPA (A) and BPA (B) concentrations in indoor dust from various microenvironments (KRH, KRL, KRO-Home, laboratory and office dust from South Korea; KWC and KWH-Car and home dust from Kuwait; PKC, PKR, PKU and PKO-Car, rural home, urban home and office dust from Pakistan; SAA, SAC and SAH-Air conditioner, car and home dust from Saudi Arabia; VNE, VNH and VNP-E-waste work shop, home and public area dust from Vietnam The box represented 25–75 percentiles, the whiskers were 10th and 90th percentiles, the lowest and highest circles were the minimum and maximum, and line inside the box showed the median) (270–3600 ng/g) in South Korea Our results are similar to those found for house and office dust from Belgium, with the concentrations in office dust (median: BPA 6530, TBBPA 75 ng/g) 5–10 times higher than those in house dust (median: BPA 1460, TBBPA 10 ng/g) (Geens et al., 2009) The use of TBBPA and BPA in electrical and electronic equipment in offices is an explanation for the elevated concentrations of these chemicals in offices However, dust samples from Pakistan did not show a significant difference in TBBPA and BPA concentrations between offices and homes Harrad et al found significantly higher concentrations of TBBPA in dust from classrooms (n = 43) and homes (n = 45) than in offices (n = 28) and cars (n = 20) (Abdallah et al., 2008) The nature and magnitude of indoor products, ventilation, and residential settings can contribute to variations in emissions of TBBPA and BPA No significant difference was found for BPA and TBBPA concentrations between dust samples collected from homes and air conditioners in Saudi Arabia No significant difference was found for TBBPA concentrations in dust collected from cars and homes in Pakistan (median: car dust 28, house dust 7.2 ng/g) and Kuwait (median: car dust 6.7, house dust 8.4 ng/g) BPA concentrations in house dust from rural homes (range: b0.5–29 ng/g) in Pakistan were significantly lower than those in urban (b0.5–800 ng/g) homes, which can be attributed to lifestyles including consumer products usage However, TBBPA concentrations in dust collected in urban homes were not significantly different from those in rural homes in Pakistan These results suggest differences in the sources of BPA and TBBPA in dust The highest TBBPA concentrations were found in dust from e-waste workshops in Vietnam, with TBBPA concentrations that ranged from 23 to 3600 ng/g; these values were significantly (p b 0.05) higher than those found for dust from homes and public areas in Vietnam A summary of median and range of concentrations for TBBPA and BPA in indoor dust analyzed in this study and those reported in earlier studies is shown in Fig S1 The concentrations of TBBPA measured in house dust for various countries in this study were similar to those reported in earlier studies: the U.S (b10–3400 ng/g, sampling year: 2006/2011) (Dodson et al., 2012), Japan (495–520 ng/g, 2006) (Takigami et al., 2009), the UK (b MQL-382 ng/g, 2007) (Abdallah et al., 2008) and Belgium (0.85–1481 ng/g, 2008) (Geens et al., 2009) The concentrations of TBBPA determined in office dust in this study were higher than those reported in the UK (bMQL-140 ng/g, 2007) 188 W Wang et al / Environment International 83 (2015) 183–191 (Abdallah et al., 2008) and Belgium (45–100 ng/g, 2008) (Geens et al., 2009) For BPA, the concentrations determined in house dust from Japan were similar to those reported previously (496–12,300 ng/g, 2010) (Liao et al., 2012a) BPA concentrations found in dust from office and laboratories were within the ranges reported from Belgium (4685–8380 ng/g, 2008), China (117–3490, 2010), Japan (11,400– 21,800, 2010), South Korea (2310–39,100, 2010) and the U.S (445–2950, 2006/2010) (Geens et al., 2009; Loganathan and Kannan, 2011; Liao et al., 2012a) 3.4 Correlations and profiles A significant (p b 0.05), but weak correlation (r = 0.27) was found between TBBPA and BPA concentrations in 284 house dust samples (only house dust samples were compared here) (Table S6), indicating the existence of multiple sources An earlier study reported that TBBPA concentrations in dust samples were not correlated with BPA concentrations (Geens et al., 2009) No significant correlation was found between TBBPA and BPF/BPS concentrations, which suggests differences in sources and emissions of these compounds A significant correlation was found between BPA and BPS (p b 0.05, r = 0.21), and between BPA and BPF (p b 0.05, r = 0.17) The contribution of each of the target compounds to the sum concentrations of all nine target chemicals analyzed in dust is presented in Fig BPA accounted for 64 ± 22% of the total concentrations TBBPA accounted for 27% of the total concentrations in dust from China, followed by Pakistan (22%) N Vietnam (15%) N India (10%) N Japan (8.4%) N South Korea (5.2%) N Saudi Arabia (4.4%) N Colombia (4.0%) N Romania (2.4%) N Kuwait (2.3%) N the U.S (1.1%) N Greece (0.41%) The proportion of BPF and BPS to the total concentrations in house dust from the U.S., Fig Composition profiles of TBBPA and BPs in house dust from 12 countries (A) and indoor dust from various microenviroments (B) (KRL, KRO-Laboratory and office dust from South Korea; KWC-Car dust from Kuwait; PKC, PKO-Car and office dust from Pakistan; SAC-Car dust from Saudi Arabia; VNE, VNP-E-waste work shop, and public area dust from Vietnam) South Korea, and Greece was higher than in other countries, indicating a greater usage of BPF and BPS in resin coatings and polycarbonate plastics in these countries (Lee et al., 2015) and hence the market shift from BPA to its alternatives The contribution of BPF was elevated in office dust in South Korea than in home dust These results agree with elevated concentrations of BPF found in sewage sludge from South Korea (Lee et al., 2015), which suggested high usage of BPF in that country The proportion of TBBPA was elevated in dust from e-waste workshop in Vietnam, which can explain that electronic products are the sources of this chemical in dust TBBPA/BPA ratios in home dust from Asian countries (0.12–0.48) were considerably higher than those found for Greece and the U.S (0.02), which suggests differences in contamination profiles among various countries Principal Component Analysis (PCA) was carried out on house dust samples from each country to identify patterns in their concentrations (Table S7) Two principal components were identified based on the component matrix (except for Kuwait), and TBBPA and BPA were identified with similar potential origin in China, Columbia, India and Greece, while with varied sources in Japan, Pakistan and Romania Furthermore, BPF and BPAF explained the predominance of total variance for samples from Korea 3.5 Exposure assessment The sources and pathways of human exposure to TBBPA are not well known (Covaci et al., 2009) We estimated daily intake (EDI) dose for TBBPA and BPs via dust ingestion for different age groups Since the number of samples collected from offices, cars and other microenvironments is small, data collected only for residential homes were taken into account for exposure calculation Median and high exposure scenarios were assessed for BPA, BPS, BPF, ∑ BPs and TBBPA based on median and 95th percentile concentrations of the target contaminants determined in home dust Because of the low frequency of detection of other BPs, they were not included in the calculation The median EDIs of TBBPA and BPA through dust ingestion have been summarized in Fig Further details (median and 95UCL) of EDIs for BPS, BPF, and ∑ BPs are shown in Fig S2 and Table S8 The highest exposure dose was found for toddlers, which can be explained by the high dust ingestion rate and the low body weight The highest EDI was found for BPA in all 12 countries, except for South Korea and Greece where BPS and BPF showed highest EDIs The highest exposure doses of ∑ BPs were found for the U.S (median, high: 0.89–9.6, 6.2– 66 ng/kg bw/day) and Greece (1.6–17, 6.2–67), whereas the lowest intakes were found for Pakistan (0.07–0.88, 0.12–1.5), Kuwait (0.19–2.3, 0.34–4.1), Romania (0.35–3.8, 0.57–6.2), and India (0.09–1.1, 0.35– 4.2) The overall median EDI of BPA was estimated to be 0.4–10, 0.21– 5.3, 0.14–3.6, 0.07–1.9, and 0.03–0.85 ng/kg bw/day for infants, toddlers, children, teenagers, and adults, respectively The daily dietary intakes of BPA and BPs in the U.S (calculated from the mean concentration of foods from the U.S.) were reported to be 195, 243; 114, 142; 91.2, 117; 48.6, 63.6; and 44.6, 58.6 ng/kg bw/day for toddlers, infants, children, teenagers, and adults, respectively (Liao and Kannan, 2013) Lorber et al (2015) reported the dietary BPA intake at 12.6 ng/kg/day for the U.S population, with canned food accounting for a majority of the exposure dose Based on the 2005–2006 U.S NHANES data for the urinary levels of BPA, the total daily intake of BPA was estimated at 35.1 ng/kg/day (Lakind and Naiman, 2011) Similarly, the daily dietary intakes of BPs in China were 646 and 664 ng/kg bw/day for adult men and women, respectively (Liao and Kannan, 2014) In comparison with the median intake doses for BPs estimated via dust ingestion in the U.S and China, diet contributes N 90% of the daily intake of BPs Our results suggest that dust ingestion is a minor contributor to total BPA exposure in the U.S., and the EDI values are much lower than the oral reference dose for BPA (50 μg/kg bw/day) (US EPA, 2008) This finding agrees well with the report that diet accounted for N 90% of the total daily BPA intake in human populations (Geens et al., 2012), potentially from the usage of BPA in epoxy can W Wang et al / Environment International 83 (2015) 183–191 189 Fig Median levels of Estimated Daily Intakes (EDI, ng/kg bw/day) of TBBPA and BPA from house dust ingestion for different age groups in 12 countries linings for foods (Guo and Kannan, 2011) In this study, a high exposure dose for BPS via dust ingestion was found for Greece (median 0.34–3.7; high 1.1–12 ng/kg bw/day) and Japan (median 0.08–0.96; high 0.35– 4.3 ng/kg bw/day) Liao et al (2012b) also found high BPS concentrations in urine from Japanese populations (0.10–15.3, with a mean of 3.47 μg/day) Japan banned the use of BPA in certain products (such as thermal receipt papers) in 2001 and BPS was used as a replacement since then (Liao et al., 2012b) Dust is an important source of chemical exposures for young children because of frequent hand-to-mouth contact For TBBPA, the highest EDI was found for infants and toddlers in Japan (median: 0.82, 0.43 ng/kg bw/day), South Korea (0.50, 0.26), and China (0.14, 0.07), and the estimated values for these three countries were 10 times higher than those found for other countries At high exposure scenario (95th percentile), the EDIs of TBBPA were the highest for infants and toddlers in China (2.5, 1.3 ng/kg bw/day), Japan (3.4, 1.8) and South Korea (1.1, 0.56), which were up to 100 times higher than those estimated for other countries In general, the overall EDIs of TBBPA ranged from 0.01 to 3.4; 0.01 to 1.8; 0.01 to 1.2; 0.003 to 0.61; 0.001 to 0.28 ng/kg bw/ day for infants, toddlers, children, teenagers, and adults, respectively, in this study The reported TBBPA exposure via dust ingestion for adults in Belgium was 0.0128 to 0.0286 ng/kg bw/day from home dust and 0.0417 ng/kg/day from office dust (Geens et al., 2009) The median exposure dose of TBBPA for UK adults via the dust ingestion was 0.002 ng/kg bw/day (Abdallah et al., 2008) In China, the average exposure dose to TBBPA via PM2.5 and PM10 inhalation was 0.0462 ng/kg bw/ day for adults (Ni and Zeng, 2013) Assuming that TBBPA concentrations in indoor dust from China were similar to those in airborne particulate matter, the contributions of dust ingestion, inhalation, and diet to TBBPA intake were estimated to be ~76%, ~4%, and ~20% for adults (Ni and Zeng, 2013) TBBPA exposure via dietary intake in China was reported to range from 0.032 to 1.3 ng/kg bw/day, with a mean value of 0.256 ng/kg bw/day (Shi et al., 2009) In our study, the median exposure doses for TBBPA via dust ingestion in China ranged from 0.01 to 0.14 ng/kg bw/day for the five age groups, which were 3.8–35% of the total TBBPA exposures In Japan, the daily exposure dose for TBBPA via dust ingestion was estimated to range from 2.0 to 4.0 ng/kg bw/day for children and 0.035 to 0.46 ng/kg bw/day for adults (Takigami et al., 2009) Takigami et al (2009) concluded that dust ingestion was an important contributor to TBBPA exposure in Japan In our study, the TBBPA exposure doses calculated for Japanese children and adults ranged in 0.29–1.2 and 0.07–0.28 ng/kg bw/day, respectively TBBPA exposure doses calculated via dust ingestion for Greece (median EDI: 0.004– 0.05 ng/kg bw/day; high EDI: 0.055–0.59 ng/kg bw/day) were higher than the reported dietary intake estimates for the Netherlands (0.04 ng/kg bw/day) (Abdallah et al., 2008) Abdallah et al (2008) reported that dust ingestion accounted for 34% and 90% of the total TBBPA exposures for adults and toddlers in the UK, respectively Geens et al (2009) reported that 7% of the total daily intakes of TBBPA for adults and 56% of the intake for toddlers in Belgium originated from dust ingestion Thus, dust ingestion is an important pathway for human exposure to TBBPA whereas diet is the major source of BPs exposures Considering the limited data available for the assessment of exposure to TBBPA, future work should focus dietary and inhalation sources of exposures To compare exposures from various microenvironments (Table S9, Fig S3), the exposure estimates were calculated based on a typical activity pattern as described previously, i.e., 63.8% home, 22.3% office, and 4.1% car for adults (Klepeis et al., 2001; U.S EPA, 2002) Exposure doses of TBBPA, BPA and BPF from offices were higher than those in houses, and laboratories, based on data for samples from Korea The exposure doses for BPA, BPF, BPS and TBBPA were lower based on data obtained for dust from cars, compared to households in Pakistan, Saudi Arabia and Kuwait, which can be explained by low exposure 190 W Wang et al / Environment International 83 (2015) 183–191 fraction A significantly higher exposure dose for TBBPA was found in e-waste workshop than homes in Vietnam, which can be attributed to the elevated contamination levels Conclusions In summary, TBBPA and BPA were detected in N 80% of the 388 indoor dust samples collected from 12 countries, indicating widespread occurrence of these phenolic compounds in the indoor environment The highest TBBPA exposures were found in house dust collected from China, Japan, and South Korea which can be explained by high consumption/production in Asian countries; whereas the highest BPA exposures were found in the U.S., Greece, and Japan The ratios of TBBPA/BPA were higher in house dust from China (0.37), Pakistan (0.48), Vietnam (0.30), India (0.12) and Japan (0.13), than in Greece (0.02) and the U.S (0.02), which suggested differences in contamination profiles and sources for these two chemicals among countries Concentration profiles of TBBPA and BPs varied among several indoor microenvironments The contribution of dust to daily intakes of TBBPA and BPA varied For BPA, dust ingestion accounted for a minor (b 10%) proportion of EDI in countries such as China and the U.S., in comparison with the dietary sources However, dust ingestion is an important pathway for TBBPA exposure, accounting for 3.8–35% (median intake scenario) of exposure in China However, the number of samples collected from each country was limited and comprehensive sampling strategies are needed in the future Acknowledgments Pierina Maza-Anaya, a youth research follow, supported by Colciencias, helped in the collection of dust samples from Colombia; Dr Dilip Kumar Kedia, Patna University, helped in the collection of dust samples from India This study was funded by a grant (1U38EH000464-01) from the Centers for Disease Control and Prevention (CDC, Atlanta, GA) to Wadsworth Center, New York State Department of Health Its contents are solely the responsibility of the authors and not 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BPS and BPP (Table S3), which were calculated from the lowest acceptable calibration standard and a nominal sample weight of 0.1 g A midpoint calibration standard (in methanol) was injected as a. .. Vietnam) South Korea, and Greece was higher than in other countries, indicating a greater usage of BPF and BPS in resin coatings and polycarbonate plastics in these countries (Lee et al., 2015) and. .. KRO-Home, laboratory and of ce dust from South Korea; KWC and KWH-Car and home dust from Kuwait; PKC, PKR, PKU and PKO-Car, rural home, urban home and of ce dust from Pakistan; SAA, SAC and SAH-Air conditioner,