Chemosphere 144 (2016) 1553–1559
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Occurrence of phthalate diesters (phthalates), p-hydroxybenzoic acid esters (parabens), bisphenol A diglycidyl ether (BADGE) and their derivatives in indoor dust from Vietnam: Implications for exposure
Tri Manh Tran
a,b, Tu Binh Minh
b, Taha A. Kumosani
c, 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, Empire State Plaza, P.O. Box 509, Albany, NY, 12201-0509, United States
bFaculty of Chemistry, Hanoi University of Science, Vietnam National University, Hanoi, 19 Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam
cBiochemistry 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 g r a p h i c a l a b s t r a c t
•Phthalates, parabens, and BADGEs were found widely in indoor dust from Vietnam.
•Median concentration of phthalates and parabens was 22,600 and 123 ng/g, respectively.
•Median concentration of BADGEs in dust was 184 ng/g.
•Median exposure to phthalates through dust ingestion by toddlers was 90 ng/kg-bw/d.
a r t i c l e i n f o
Article history:
Received 14 June 2015
Received in revised form 3 September 2015 Accepted 7 October 2015
Available online 26 October 2015 Handling editor: Ian Cousins Keywords:
Indoor dust Phthalates Parabens BADGEs Human exposure
a b s t r a c t
Phthalate diesters (phthalates), esters ofp-hydroxybenzoic acid (parabens), and bisphenol A diglycidyl ether (BADGE) are used in personal care products, food packages, household products, or pharmaceuti- cals. These compounds possess endocrine-disrupting potentials and have been reported to occur in the environment. Nevertheless, no previous studies have reported the occurrence of these compounds in in- door dust from Vietnam. In this study, nine phthalates, six parabens, and four BADGEs were determined in indoor dust samples collected from Hanoi, Hatinh, Hungyen, and Thaibinh, in Vietnam. Total concen- trations of phthalates, parabens, and BADGEs in indoor dust ranged from 3440 to 106,000 ng/g (median:
22,600 ng/g), 40–840 ng/g (median: 123 ng/g), and 23 to 1750 ng/g (median: 184 ng/g), respectively.
Based on the measured median concentration of phthalates, parabens, and BADGEs in indoor dust, we estimated human exposure doses to these compounds through indoor dust ingestion for various age groups. The exposure doses to phthalates, parabens, and BADGEs decreased with age and ranged from 19.4 to 90.4 ng/kg-bw/d, 0.113–0.528 ng/kg-bw/d, and 0.158–0.736 ng/kg-bw/d, respectively. This is the first study on the occurrence and human exposure of phthalates, parabens, and BADGEs in indoor dust from Vietnam.
© 2015 Elsevier Ltd. All rights reserved.
∗ Corresponding author. Wadsworth Center, Empire State Plaza, P.O. Box 509, Al- bany, NY, 12201-0509, United States.
E-mail address:[email protected](K. Kannan).
http://dx.doi.org/10.1016/j.chemosphere.2015.10.028 0045-6535/© 2015 Elsevier Ltd. All rights reserved.
1. Introduction
Owing to the widespread use of phthalates, parabens, and BADGEs as additives or preservatives in various consumer prod- ucts, contamination by these compounds in the indoor envi- ronment is inevitable. The ubiquitous occurrence of phthalates, parabens, and BADGEs in the indoor environment in many coun- tries has been reported in recent studies (Wang et al., 2012a; Guo and Kannan, 2013; Guo et al., 2014; Ma et al., 2014). These com- pounds possess endocrine-disrupting potentials, and, therefore, hu- man exposure to these chemicals is a public health concern.
Phthalates are used in various consumer, household, and indus- trial products as plasticizers. In cosmetics and personal care prod- ucts, diethyl phthalate (DEP) and di-n-butyl phthalate (DBP) were found at concentrations as high as 25,500 and 24,300
μ
g/g, re-spectively (Koniecki et al., 2011; Guo and Kannan, 2013; Guo et al., 2014). Phthalates were reported to occur in indoor air at hundreds to thousands of ng/m3 and in indoor dust at hundreds to thou- sands of ng/g (Fromme et al., 2004, 2005; Bergh et al., 2011; Guo and Kannan, 2011; Bergh et al., 2012; Kubwabo et al., 2013; Blan- chard et al., 2014; Tran and Kannan, 2015). Phthalates elicit repro- ductive and developmental toxicities in laboratory animals (Gray et al., 2000, 2006; Boberg et al., 2008). Gaspar et al. (2014) re- ported that 82–89% of children in California had DBP exposures ex- ceeding the reproductive health benchmarks. Therefore, to develop strategies to mitigate exposures, a comprehensive assessment of sources of human exposure to phthalates is necessary.
Parabens are widely used in foods, cosmetics, and pharmaceu- ticals (Soni et al., 2005; Fei et al., 2011; SCCS, 2011). The concen- trations of five parabens in foods from the USA were as high as 409 ng/g (Liao et al., 2013b) and ranged from 0.839 ng/g in bev- erages to 100 ng/g in vegetables collected from China (Liao et al., 2013a). Wang et al. (2012a)reported median concentration of six parabens in indoor dust samples from the USA (1560 ng/g), China (573 ng/g), South Korea (2180 ng/g), and Japan (1850 ng/g). Several earlier studies have reported the occurrence of parabens in human blood, urine, and milk (Darbre et al., 2004; Schlumpf et al., 2010;
Frederiksen et al., 2011). The concentrations of the sum of four parabens in urine samples collected from Chinese young adults ranged from 0.82 to 728 ng/mL (Ma et al., 2013), and concentra- tions as high as 10,000 ng/mL were found in urine from Chinese adult females (Wang et al., 2013). Studies have reported toxic ef- fects of parabens in laboratory animals (Miller et al., 2001; Okubo et al., 2001; Byford et al., 2002; Oishi, 2002a, 2002b; Golden et al., 2005; Darbre and Harvey, 2008; Kim et al., 2011). In an effort to re- duce the risk of exposure to parabens, Denmark announced a ban on the use of two parabens, propyl- (PrP) and butyl-paraben (BuP), their isoforms, and salts in children’s cosmetic products (SCCS, 2011).
Bisphenol A diglycidyl ether (BADGE) is a building block of epoxy resins and is used to make the inner surface coating of food cans (Wang et al., 2012a, 2012b). BADGE is a reactive molecule, and, following contact with aqueous and acidic media, chlorinated and hydrated derivatives such as bisphenol A (2,3-dihydroxypropyl) glycidyl ether (BADGE·H2O), bisphenol A (2,3-dihydroxypropyl) ether (BADGE·2H2O), and bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether (BADGE·HCl·H2O) (collectively referred to in this study as BADGEs) can be formed. The toxic effects of BADGEs have been reported in several laboratory studies (Nakazawa et al., 2002; Satoh et al., 2004; Ramilo et al., 2006;
Hyoung et al., 2007; Yang et al., 2010). Studies also have reported the occurrence of BADGEs in foodstuffs (Lintschinger and Rauter, 2000; Petersen et al., 2003; Coulier et al., 2010) and in human urine from the USA and China (Wang et al., 2012b), Japan (Hanaoka et al., 2002), Greece (Asimakopoulos et al., 2014), and India (Xue et al., 2015). An earlier study reported median concentrations of
BADGEs in dust samples collect from the USA, China, South Korea, and Japan at 1350, 1410, 2380, and 2020 ng/g, respectively (Wang et al., 2012a). Prior to this study, no study reported the occurrence of phthalates, parabens, or BADGEs in dust from Vietnam. In this study, nine phthalates, six parabens, and four BAGDEs were de- termined in 46 indoor dust samples collected from four cities in Vietnam. Based on the concentrations measured in dust, human exposure to these compounds via dust ingestion was estimated.
2. Materials and methods
2.1. Standards and chemicals
Analytical grade acetone was purchased from Macron Chemical (Nashville, TN, USA), and formic acid (98.2%) was purchased from Sigma–Aldrich (St. Louis, MO, USA). Hexane, dichloromethane, and methanol (HPLC grade) were purchased from J. T. Baker (Phillips- burg, NJ, USA). Milli-Q water was prepared using an ultrapure water system (Barnstead International, Dubuque, IA, USA). Nine phthalate diesters, viz., dimethyl phthalate (DMP), diethyl phtha- late (DEP), diisobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), di-n-hexyl phthalate (DNHP), benzyl butyl phthalate (BzBP), di- cyclohexyl phthalate (DCHP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DOP), along with their corresponding d4 (deuterated) internal standards, with a purity of >99%, were purchased from AccuStandard Inc. (New Haven, CT, USA). Methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), butyl paraben (BuP), benzyl paraben (BzP), and heptyl paraben (HepP) were purchased from AccuStandard, Inc. Bisphenol A diglycidyl ether (BADGE, ≥95%), bisphenol A (2,3-dihydroxypropyl) glycidyl ether (BADGE·H2O,≥95%), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether (BADGE·HCl·H2O, ≥95%), and bisphe- nol A (2,3-dihydroxypropyl) ether (BADGE·2H2O, ≥97%) were purchased from Sigma–Aldrich (Table S1; Supporting Informa- tion).13C-labeled 2-hydroxy-4-methoxybenzophenone (13C12-BP-3) (99%), 13C6-MeP (99%), 13C6-BuP (99%), and 13C12-BADGE (99%) were purchased from Cambridge Isotope Laboratories (Andover, MA, USA).
2.2. Sample collection
Indoor dust samples were collected during April and May 2014 in Hanoi (n =18), Hatinh (n=12), Hungyen (n= 8), and Thaib- inh (n = 8), Vietnam. The sampling locations were grouped into four categories: homes (living rooms and kitchens,n=16), super- markets/grocery shops, electronic stores and pharmacies; (n=18), laboratories (Hanoi only,n=7), and offices (n=5); all of the sites were built after 2000. Floor dust samples were collected using a vacuum cleaner or by sweeping the floor directly with a broom.
Samples were stored in polyethylene bags and then placed in glass jars at 4°C until analysis.
2.3. Sample preparation
Prior to analysis, dust samples were sieved and homogenized by passage through a 150
μ
m sieve. Fifty nanograms of d4-phthalates (except for d4-DEHP, for which 250 ng was spiked) were spiked onto 50–60 mg of dust samples, as internal standards. The spiked dust samples were equilibrated for 30 min at room temperature.The dust samples were extracted three times by shaking in an or- bital shaker (Eberbach Corp., Ann Arbor, MI, USA) with a 4 mL mix- ture of dichloromethane (DCM) and hexane (3:1, v:v) for 10 min each time. After shaking, samples were centrifuged at 2000g for 5 min (Eppendorf Centrifuge 5804, Hamburg, Germany), and the supernatant was transferred into a 15 mL glass tube. The extracts
T.M. Tran et al. / Chemosphere 144 (2016) 1553–1559 1555
were concentrated to 1 mL under a gentle stream of nitrogen, fil- tered through a regenerated cellulose membrane filter (PhenexTM, pore size: 0.2
μ
m), and then transferred into a GC vial for the anal- ysis of phthalates.For the analysis of parabens and BADGEs, 200–250 milligrams of dust were accurately weighed and spiked with 20 ng 13C6- MeP,13C6-BuP, and13C12-BADGE, as internal standards. The spiked dust samples were equilibrated for 30 min at room temperature.
The samples were extracted with 5 mL of methanol/Milli-Q water mixture (2:1, v/v) by shaking in an oscillator shaker for 60 min, and the mixture was centrifuged at 4500g for 5 min. The super- natant was transferred into a glass tube. The extraction was re- peated twice. The combined extracts were concentrated to∼4 mL under a gentle nitrogen stream. The extract was diluted to 10 mL with 0.2% formic acid (pH 2.5). The extract was purified by passage through Oasis MCX®cartridges (60 mg/cm3; Waters Corp., Milford, MA, USA), preconditioned with 5 mL of methanol and 5 mL of wa- ter. The diluted sample extract was loaded, followed by passage of 10 mL methanol/Milli-Q water (1:3, v/v) and 5 mL of Milli-Q wa- ter. After drying the cartridge under a gentle nitrogen stream, the target compounds were eluted with 7 mL of methanol. The extract was concentrated under a gentle nitrogen stream and analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS).
2.4. Instrumental analysis 2.4.1. GC/MS
Nine phthalates were analyzed on a gas chromatograph (6890 GC) (Agilent Technologies, Santa Clara, CA, USA) coupled with a 5973 mass spectrometer (MS). A fused-silica capillary col- umn (HP-5MS; Agilent; 5% diphenyl 95% dimethylpolysiloxane, 30 m × 0.25 mm i.d.; 0.25
μ
m film thickness) was used for the separation of phthalates. The oven temperature was programmed from 80°C (held for 1 min) to 180°C at 12°C/min (held for 1 min), increased to 230°C at 6°C/min, then to 270°C at 8°C/min (held for 2 min), and finally increased to 280°C at 30°C/min (held for 12 min). Ion fragmentsm/z163, 279, and 149 were monitored for the quantification of DMP, DNOP, and seven other phthalate di- esters, respectively. The fragment ionsm/z177 for DEP,m/z233 for DIBP and DBP, m/z 223 andm/z 206 for BzBP, m/z 167 for DCHP, m/z167 andm/z 279 for DEHP, andm/z279 for DNHP were mon- itored for the confirmation of the target compounds. Ion fragment m/z167 was monitored for d4-DMP andm/z153 for other internal standards (Guo et al., 2014).2.4.2. LC/MS/MS
Parabens and BADGEs were measured by an Applied Biosys- tems API 2000 electrospray triple quadrupole mass spectrometer (ESI-MS/MS; Applied Biosystems, Foster City, CA, USA), coupled with an Agilent 1100 series HPLC (Agilent Technologies) equipped with a binary pump and an autosampler. Ten microliters of the sample extracts were injected onto an analytical column (Betasil® C18, 100×2.1 mm column; Thermo Electron Corp., Waltham, MA, USA), which was connected to a Javelin guard column (Betasil® C18, 20 × 2.1 mm column; Thermo Electron Corp.). The mobile phase comprised methanol (A) and 10% methanol in Milli-Q water that contained 2 mM (0.15 g/L) ammonium acetate (B) at a flow rate of 300
μ
L/min. The proportion of methanol was linearly in- creased from 20% to 75% in 5 min, then increased to 95% in 3 min and held for 8 min, and then reverted to 20% methanol in 1 min and held for 5 min. The MS/MS was operated in multiple reac- tion monitoring (MRM) negative and positive ionization modes for parabens and BADGEs, respectively. The MRM transitions were set at 151>92 for MeP, 165>92 for EtP, 179>92 for PrP, 193>92 for BuP, 227 > 92 for BzP, 157 > 98 for 13C6-MeP, 199 > 98 for 13C6-BuP, 358 > 191 for BADGEs, 376> 209 for BADGE·H2O,394> 209 for BADGE·2H2O, 412 > 227 for BADGE·HCl·H2O, and 364>197 for d6-BADGE (Wang et al., 2012a,b; Ma et al., 2013).
2.5. Quality assurance and quality control (QA/QC)
The contamination of phthalates arising from laboratory prod- ucts and reagents was examined in our laboratory (Guo and Kan- nan, 2011, 2012, 2013; Guo et al., 2011b, 2012, 2014). Efforts to re- duce background levels of phthalates in the analytical procedure were followed. All glassware was baked at 450°C for 20 h prior to use. Solvents were used directly from newly opened glass bottles.
Prior to instrumental analysis, hexane was injected into the GC- MS until the background levels became stable. Hexane also was injected between every sample as a check for background con- tamination and carry-over. The calibration curve was linear over a concentration of 0.3–200 ng/mL for individual phthalates, and the regression coefficient (R 2) was≥0.99. DEP (2.5–7.0 ng/g), DBP (2.0–5.5 ng/g), DIBP (1.5–8.5 ng/g), and DEHP (3.6–24.5 ng/g) were found in blanks. Fifty nanograms of d4-phthalates (except for d4- DEHP, for which 250 ng were spiked) were spiked into blanks and passed through the entire analytical procedure. The average recov- eries of d4-phthalates in procedural blanks and samples ranged from 76 to 112% and from 68 to 109%, respectively. The mean re- coveries of target compounds in spiked matrices were 66–98%. The limits of quantifications (LOQs) were 12 ng/g for DOP and 5.0 ng/g for other phthalates.
For parabens and BADGEs, procedural blanks (n = 12) con- tained trace levels of MeP (mean value: 0.3 ng/g), EtP (0.1 ng/g), PrP (0.1 ng/g), BADGE·H2O (0.7 ng/g), and BADGE.2H2O (1 ng/g).
These values were subtracted from sample concentrations. Twenty nanograms of13C6-MeP (for MeP and EtP),13C6-BuP (for PrP, BuP, BzP, and HeP), and d6-BADGE (for BADGEs) were spiked into proce- dural blanks and every sample. Recoveries of internal standards in procedural blanks and samples ranged from 76 to 103% and from 69 to 97%, respectively. Recoveries of target analytes (six parabens and four BADGEs, spiked at 20 ng each) in procedural blanks and spiked matrices ranged from 70 to 105% and from 67 to 116%, re- spectively. Instrumental calibration was verified by the injection of 10-point calibration standards (at concentrations ranging from 0.08 to 100 ng/mL for parabens and 0.2–100 ng/mL for BADGEs), andR
2 was≥0.99. The LOQs were 0.4 ng/g for parabens and 1 ng/g for BADGEs, which was calculated as 10 times the valid lowest accept- able calibration standard and a normal sample weight of 200 mg.
2.6. Statistical analysis
All of the reported concentrations in dust samples were sub- tracted from the mean values found in procedural blanks. Statisti- cal analysis was performed with Microsoft Excel (Microsoft Office 2010) and Graph Pad Prism, V. 5.0 software.
3. Results and discussion
3.1. Phthalates in indoor dust
The mean, median, and range of concentrations of phtha- lates found in dust samples collected from Vietnam are shown in Table 1. DEP, DIBP, DBP, BzBP, and DEHP were found in all samples, whereas DOP, DMP, DCHP, and DNHP were detected in 96.9%, 69.6%, 60.0%, and 45.6% of the samples, respectively.
The sum concentration of nine phthalates in dust ranged from 3440 to 106,000 ng/g (median: 22,600 ng/g; mean: 30,200 ng/g).
Dust samples collected from supermarkets contained the high- est concentrations, ranging from 8030 to 106,000 ng/g (median:
32,700 ng/g). The lowest phthalate concentrations were found in dust samples from offices (range: 4500 to 17,000; median:
T.M.Tranetal./Chemosphere144(2016)1553–1559 Table 1
Concentrations of phthalates, parabens, and BADGEs in indoor dust samples collected from four cities in Vietnam (ng/g).
Phthalates Parabens BADGEs
DMP DEP DIBP DBP DNHP BzBP DCHP DEHP DOP ƩPHTs MeP EtP PrP BuP BzP HepP ƩPARs BADGE BADGE·H2O BADGE·2H2O BADGE·HCl·H2O ƩBADGES Homes, n=16 Range n.d. –
685 9.49 –362
17.9 –968
73.7 –4910
n.d.
–259 28.0 –4600
n.d.
–298 2080 –76,500
17.5 –1450
3440 –79,300
6.73 –533
2.0 –92.0
5.95 –261
n.d.
–47.0 n.d.
–51.8 n.d.
–2.25 46.9 –842
n.d.
–34.5 1.79 –80.5
10.9 –1630
2.49 –417
27.7 –1650
Mean 90.5 76.6 419 1110 37.5 968 49.4 23,800 312 26,800 140 34.2 50.7 11.7 7.30 0.70 245 9.00 27.4 243 44.2 324
Median 20.4 20.9 425 470 7.44 217 16.9 19,400 189 22,600 101 27.9 31.4 6.53 0.63 <0.5 205 4.78 26.3 53.4 9.90 114
DR% 87.5 100 100 100 50 100 62.5 100 100 100 100 100 81.3 56.3 50.0 68.8 100 100 100
Shops/
supermarkets, n=18
Range n.d.
–738 7.75 –45.6
294 –4580
408 –6330
n.d.
–465 17.0 –9780
n.d.
–137 6580 –102,000
37.1 –1070
8030 –106,000
21.6 –78.7
1.93 –99.9
1.82 –135
1.11 –250
n.d.
–19.6 n.d.
–2.79 40.8 –431
n.d.
–172 1.79 –255
7.58 –1300
n.d.
–240
23.2 –1750
Mean 50.1 18.4 1180 1570 39.6 1270 19.3 35,800 258 40,200 50.7 19.1 25.6 36.8 3.41 <0.5 136 35.1 73.4 343 39.6 491
Median 9.41 16.1 791 950 <5.0 218 6.44 28,900 144 32,700 47.6 9.55 9.39 17.7 1.56 <0.5 96.7 12.6 38.6 167 15.4 260
DR% 58.8 100 100 100 30.8 100 47.0 100 100 100 100 100 100 72.2 11.1 72.2 100 100 94.4
Laboratories, n=7
Range 6.32 –35.3
8.81 –300
310 –1390
297 –2120
n.d.
–106 237 –5790
n.d.
–48.9 15,000 –46,500
421 –4960
421 –53,300
22.9 –128
6.24 –40.0
6.14 –234
14.2 –116
n.d.
–2.38
n.d. 115 –326
5.43 –73.1
22.5 –146
73.9 –452
4.41 –178
115 –666
Mean 16.0 62.5 749 786 31.0 1420 16.6 23,400 1300 27,800 78.0 19.8 57.6 66.4 0.73 n.d. 223 32.5 67.7 226 38.9 365
Median 11.3 20.7 513 612 2.50 422 <5.0 19,500 487 22,200 77.9 15.0 37.9 78.3 <0.5 n.d. 211 37.2 66.1 151 16.1 225
DR% 85.7 100 100 100 42.9 100 42.9 100 100 100 100 100 100 57.1 0.0 100 100 100 100
Offices, n=5 Range n.d.
–202 8.09 –13.1
116 –2620
113 –3470
44.7 –373
47.9 –2470
n.d.
–15.4 2270 –10,000
10.5 –353
4500 –17,000
25.0 –92.5
2.95 –38.6
1.44 –14.0
n.d.
–34.2 n.d.
–8.55
n.d. 40.0 –144
n.d.
–29.1 8.02 –58.2
63.2 –337
4.25 –11.4
94.9 –353
Mean 49.0 9.36 824 1090 128 1190 <5.0 5340 116 8280 55.4 15.9 7.68 16.4 2.89 n.d. 98.4 12.5 29.9 168 8.21 219
Median 2.50 8.50 392 738 56.4 785 <5.0 3710 36.7 5370 51.3 13.6 7.36 15.9 1.56 n.d. 120 9.86 26.7 136 8.58 213
DR% 33.3 100 100 100 50.0 100 16.7 100 50.0 100 100 100 80.0 80.0 – 80.0 100 100 100
Total, n=46 Range n.d.
–738 7.75 –363
18.0 –4580
73.7 n.d.
–465 17.0 –9780
n.d.
–298 2080 –102,000
10.5 –4960
3440 –106,000
6.73 –533
1.93 –99.9
1.44 –261
n.d.
–250 n.d.
–51.8 n.d.
–2.25 40.0 –842
n.d.
–172 1.79 –255
7.58 –1630
n.d.
–417
23 –1750
Mean 58.8 44.4 811 1240 47.2 1180 27.6 26,400 419 30,200 86.4 24.1 37.3 30.4 4.30 <0.5 183 23.4 52.3 274 38.3 388
Median 14.0 16.8 562 737 <5.0 243 <5.0 19,800 183 22,600 58.2 12.7 15.0 14.9 0.92 <0.5 132 11.1 28.0 129 11.4 184
DR% 69.6 100 100 100 45.6 100 50.0 100 96.6 100 100 100 91.3 65.2 21.7 76.1 100 100 97.8
ƩPHTs,ƩPARs, andƩBADGEs: Total concentrations of nine phthalates, six parabens, and four BADGEs, respectively. DR%: per cent detection rates. n.d.: not detectable. “<”: lower than limit of quantitation (LOQ). The LOQs were 5.0, 0.5, and 1.0 ng/g for phthalates, parabens, and BADGEs, respectively.
T.M. Tran et al. / Chemosphere 144 (2016) 1553–1559 1557
8280 ng/g). The overall median concentrations of phthalates in in- door dust from Vietnam were 13 and 18 times lower than those reported from China (295,000 ng/g) and the USA (396,000 ng/g), respectively (Guo and Kannan, 2011). The lower concentrations of phthalates in indoor dust from Vietnam than from China resemble the urinary phthalate metabolite concentrations observed for the Vietnamese population (median: 133 ng/mL), which were approx- imately two-to threefold lower than the values reported for the Chinese population (median: 234–331 ng/mL) (Guo et al., 2011a, b). These results imply that phthalate concentrations in dust can be a predictor of urinary concentrations.
The profile of the phthalates in indoor dust from Vietnam is shown inFig. 1a. DEHP was the most abundant compound in in- door dust from Vietnam. The concentration of DEHP in dust sam- ples ranged from 2080 to 102,000 ng/g (median: 19,800 ng/g), followed by DBP (range: 73.7 to 1240 ng/g; median: 737 ng/g) and DIBP (range: 18 to 4580 ng/g; median: 562 ng/g). Similarly, DEHP was found at the highest concentration in indoor dust from Canada (median: 462,000 ng/g) (Kubwabo et al., 2013), France (median: 289,000 ng/g) (Blanchard et al., 2014), China (median:
228,000 ng/g), and the USA (median: 304,000 ng/g) (Guo and Kan- nan, 2011).
Among the four cities surveyed, the highest concentration of the sum of the nine phthalates was found in dust samples from Hanoi (median: 32,000 ng/g), followed by Hungyen (23,000 ng/g), Hatinh (16,000 ng/g), and Thaibinh (13,000 ng/g). Hanoi is the most populous urban center in Vietnam (2.6 million), followed by Thaibinh (1.8 million), Hatinh (1.3 million), and Hungyen (1.1 mil- lion) (Vietnam Government, General Statistics Office, 2013). These results suggest that dust from urban areas contains elevated con- centrations of phthalates.
3.2. Parabens in indoor dust
Total concentrations of sum of the six parabens in dust sam- ples ranged from 40.0 to 842 ng/g (median: 132 ng/g). Among various microenvironments studied, dust samples collected from homes and laboratories contained similar median concentrations of parabens, at 205 and 211 ng/g, respectively; these concentra- tions were two times higher than in dust samples from retail stores (96.7 ng/g) and offices (120 ng/g). Paraben concentrations
in indoor dust from Vietnam were 12, 4, 17, and 14 times lower than those reported in dust samples from the USA (median: 1560), China (573), South Korea (2180), and Japan (1850), respectively (Wang et al., 2012a). Individual paraben concentrations in indoor dust from Vietnam were 30 times lower than in dust samples from Spain (median concentrations of MeP and PrP were at 2440 and 910 ng/g, respectively) (Ramírez et al., 2011). A major source of parabens in the indoor environment is cosmetics and personal care products (Dodson et al., 2012).
Among parabens, MeP was the most abundant compound, with a median concentration of 58.2 ng/g, followed by PrP (15.0 ng/g), BuP (14.9 ng/g), and EtP (12.7 ng/g). MeP and PrP concentra- tions were significantly correlated (Fig. S1; Supporting Informa- tion). These results suggest that MeP and PrP coexist in many con- sumer products (Soni et al., 2005; SCCS, 2011). The total concen- trations of parabens in dust from the four cities were not signifi- cantly different (p>0.05), although the highest levels were found in samples from Hanoi (median: 196 ng/g), followed by Hatinh (124 ng/g), Thaibinh (122 ng/g), and Hungyen (100 ng/g).
3.3. BADGE and its derivatives in indoor dust
The overall sum concentrations of BADGEs in indoor dust from Vietnam ranged from 23 to 1750 ng/g (median: 184). The con- centrations of BADGEs in dust from Vietnam were 7, 8, 13, and 11 times lower than those reported from the USA (1350 ng/g), China (1410 ng/g), South Korea (2380 ng/g), and Japan (2020 ng/g), respectively (Wang et al., 2012a). The median concentrations of BADGEs in dust collected from shops/supermarkets, laboratories, offices, and homes were 260, 225, 213, and 114 ng/g, respec- tively. BADGE·H2O and BADGE·2H2O were the predominant com- pounds found in dust, followed by BADGE·HCl·H2O (detection rate:
97.8%), and BADGE (detection rate: 76.1%). The distribution profile of BADGEs in indoor dust from Vietnam was similar to that re- ported for the USA, China, South Korea, and Japan (Wang et al., 2012a).
Among the BADGEs, BADGE·2H2O was measured at the highest concentrations, ranging from 7.58 to 1630 ng/g (median: 129 ng/g), followed by BADGE·H2O (1.79–255 ng/g; median: 28.0 ng/g).
The concentrations of BADGE and BADGE·HCl·H2O were similar
Fig. 1. Distribution profiles of phthalates (a), parabens (b), and BADGEs (c) in indoor dust collected from various locations in Vietnam.
(11 ng/g) and were 12 times lower than the concentration found for BADGE·2H2O.
BADGE·2H2O and BADGE·HCl·H2O are stable hydrolysis products of BADGE. BADGE·H2O is formed by the reaction of BADGE with moisture and humidity in the atmosphere (Wang et al., 2012a).
The toxicity of hydrated products of BADGE was reported to be significantly higher than that of BADGE itself (Nakazawa et al., 2002). In this study, the sum of concentrations of BADGE·2H2O and BADGE·HCl·H2O [i.e., BADGE·2H2O + BADGE·HCl·H2O] were pos- itively correlated with the sum of concentrations of BADGE and BADGE·H2O [i.e., BADGE + BADGE·H2O] (p < 0.0004) (Fig. S2;
Supporting Information), which suggests similarity in sources of release for these compounds. The highest concentration of BADGE·2H2O and BADGE·HCl·H2O found in indoor dust was 1640 ng/g, and the corresponding value for BADGE and BADGE·H2O was 427 ng/g. Very few studies have reported the occurrence of BADGE in indoor dust, and the presence of high levels of these compounds in dust suggests the need for further studies to assess the sources and exposures in humans.
Concentrations of BADGEs in dust samples were significantly different among the four cities (p < 0.005). The highest concen- tration of the sum of the four BADGEs was found in indoor dust from Hungyen (median: 671 ng/g) followed by Thaibinh (297 ng/g), Hanoi (150 ng/g), and Hatinh (124 ng/g). The reason for this pat- tern is unclear, and further studies are needed to delineate the sources of BADGEs.
In general, phthalates were more abundant in indoor dust from Vietnam than were parabens and BADGEs. The concentrations of phthalates in indoor dust were around 100 times higher than that of both parabens and BADGEs. No marked correlations were iden- tified between the concentration profiles of three classes of con- taminants in indoor dust of different microenvironments.
3.4. Human exposure to phthalates, parabens, and BADGEs through dust ingestion
We estimated the daily intake of phthalates, parabens, and BADGEs through dust ingestion (EDIdi) by following the meth- ods described in several previous studies (Guo and Kannan, 2011;
Wang et al., 2012a; Liao et al., 2012). In this study, the average body weights (bw) for Vietnamese was applied as: infants (6–
12 months): 8 kg, toddlers (1–5 yrs): 15 kg, children (6–11 yrs):
27 kg, teenagers (12–18 yrs): 50 kg, and adults (≥19 yrs): 70 kg (Vietnam encyclopedic knowledge, 2014). The mean dust ingestion rates were 0.03 g/d for infants and 0.06 g/d for toddlers, children, teenagers, and adults (U.S. Environmental Protection Agency, 2008).
The daily intake, DI, which has the units of ng/kg-bw/d, was deter- mined by Eq.(1):
DI=Cdustf
M (1)
where Cdust is the concentration in dust (ng/g), f is the dust in- gestion rate (g/d), and M is the body weight (kg). The estimated exposure doses to phthalates through dust ingestion (based on the median concentrations) were in the ranges of 19.4 ng/kg-bw/d (for adults) to 90.4 ng/kg-bw/d (for toddlers) (Table 2). The exposure to DEHP was the highest through dust ingestion; DEHP exposure doses were 74.3, 79.2, 44.0, 23.8, and 17.0 ng/kg-bw/d for infants, toddlers, children, teenagers, and adults, respectively. The exposure of Vietnamese to phthalates through indoor dust ingestion was 10–
12 times lower than exposure doses reported for Chinese and 12–
28 times lower than exposure doses reported for Americans (Guo and Kannan, 2011).
The exposure doses to parabens and BADGEs through dust ingestion decreased with increasing age. The exposure doses to parabens ranged from 0.113 (adult) to 0.528 ng/kg-bw/d (toddlers),
Table 2
Median estimated daily intakes (EDI) of phthalates, parabens, and BADGEs through dust ingestion (EDIdi, ng/kg-bw/d) for various age groups in Vietnam.
Infants Toddlers Children Teenagers Adults
Phthalates 84.8 90.4 50.2 27.1 19.4
Parabens 0.495 0.528 0.293 0.158 0.113
BADGEs 0.690 0.736 0.409 0.221 0.158
and the corresponding values for BADGEs were from 0.158 (adult) to 0.736 ng/kg-bw/d (toddlers). The exposure of Vietnamese to parabens through dust ingestion was similar to those reported for Chinese (from 0.2 for adult to 0.98 ng/kg-bw/d for children) and 10 times lower than those reported for Koreans (1.11–5.42 ng/kg- bw/d) and Japanese (1.18–5.38 ng/kg-bw/d) (Wang et al., 2012a).
The exposure of Vietnamese to BADGEs through dust ingestion was three times lower than those reported for Chinese (0.66–
3.22 ng/kg-bw/d) and 10 times lower than those reported for Ko- reans (1.38–6.77 ng/kg-bw/d) and Japanese (1.42–6.45 ng/kg-bw/d) (Wang et al., 2012a).
The exposure to the three compound classes in indoor dust col- lected from homes was estimated for several age groups (Table S2).
There were small differences in exposure doses to these com- pounds among several age groups, which is attributed to varia- tions in body weight and dust ingestion rates. Overall, this is the first study to report the occurrence of emerging contaminants such as phthalates, parabens, and BADGEs in indoor dust from Vietnam.
Notable concentrations of these chemicals were found in dust, and the measured concentrations were comparable to or lower than those reported in other developed countries. The exposure of Viet- namese to these emerging environmental chemicals through dust ingestion was lower than those reported in other Asian coun- tries, such as Korea and Japan. Future studies are needed to assess the health outcomes associated with exposure to these endocrine- disrupting chemicals in Vietnam.
Acknowledgments
This study was funded in part by a grant from by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, un- der grant no. 167-130-1435. The authors, therefore, acknowledge with thanks DSR technical and financial support.
Appendix A. Supplementary data
Supplementary data related to this article can be found athttp:
//dx.doi.org/10.1016/j.chemosphere.2015.10.028.
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