Article pubs.acs.org/est
Occurrence of Eight Bisphenol Analogues in Indoor Dust from the United States and Several Asian Countries: Implications for Human Exposure Chunyang Liao,†,‡ Fang Liu,† Ying Guo,† Hyo-Bang Moon,§ Haruhiko Nakata,∥ Qian Wu,† and Kurunthachalam Kannan†,⊥,* †
Wadsworth 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, New York 12201-0509, United States ‡ Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai, Shandong 264003, China § Department of Environmental Marine Sciences, College of Science and Technology, Hanyang University, Ansan 426-791, South Korea ∥ Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan ⊥ International Joint Research Center for Persistent Toxic Substances, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China S Supporting Information *
ABSTRACT: Bisphenol A has been reported to be a ubiquitous contaminant in indoor dust, and human exposure to this compound is well documented. Information on the occurrence of and human exposure to other bisphenol analogues is limited. In this study, eight bisphenol analogues, namely 2,2-bis(4-hydroxyphenyl)propane (BPA), 4,4′-(hexafluoroisopropylidene)diphenol (BPAF), 4,4′-(1-phenylethylidene)bisphenol (BPAP), 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4′-dihydroxydiphenylmethane (BPF), 4,4′-(1,4-phenylenediisopropylidene)bisphenol (BPP), 4,4′- sulfonyldiphenol (BPS), and 4,4′-cyclohexylidenebisphenol (BPZ), were determined in indoor dust samples (n = 156) collected from the United States (U.S.), China, Japan, and Korea. Samples were extracted by solid−liquid extraction, purified by automated solid phase extraction methods, and determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total concentrations of bisphenols (∑BPs; sum of eight bisphenols) in dust were in the range of 0.026−111 μg/g (geometric mean: 2.29 μg/g). BPA, BPS, and BPF were the three major bisphenols, accounting for >98% of the total concentrations. Other bisphenol analogues were rare or not detected, with the exception of BPAF, which was found in 76% of the 41 samples collected in Korea (geometric mean: 0.0039 μg/g). The indoor dust samples from Korea contained the highest concentrations of both individual and total bisphenols. BPA concentrations in dust were compared among three microenvironments (house, office, and laboratory). The estimated median daily intake (EDI) of ∑BPs through dust ingestion in the U.S., China, Japan, and Korea was 12.6, 4.61, 15.8, and 18.6 ng/kg body weight (bw)/day, respectively, for toddlers and 1.72, 0.78, 2.65, and 3.13 ng/kg bw/day, respectively, for adults. This is the first report on the occurrence of bisphenols, other than BPA, in indoor dust.
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INTRODUCTION
Due to endocrine disrupting chemicals’ (EDCs) potential to adversely affect human health, concern about human exposure is growing.1,2 EDCs consist of a wide range of substances, including organochlorine pesticides, organotins, polychlori© 2012 American Chemical Society
Received: Revised: Accepted: Published: 9138
January 1, 2012 January 1, 2012 July 11, 2012 July 11, 2012 dx.doi.org/10.1021/es302004w | Environ. Sci. Technol. 2012, 46, 9138−9145
Environmental Science & Technology
Article
Figure 1. Chemical structures of several bisphenols analyzed in the present study.
BPA is a weak estrogen receptor agonist and its toxicity to laboratory animals has been well documented.3,4,8 Considerable controversies surround the safety of BPA, and this compound is being replaced with alternatives in certain products. Some of the alternatives include compounds that are similar in structure to BPA. Limited studies have shown that BPS, BPB, and BPF possess toxicities (e.g., acute toxicity, genotoxicity, and estrogenic activity) similar to BPA.12,13,25−27 One study showed that BPB and BPAF are potent human pregnane X receptor agonist.28 Another study compared biodegradation of a series of bisphenols and showed that BPF and BPS are more resistant to degradation than BPA.29 Given the similarity in molecular structure of the bisphenol analogues, it is expected that these compounds will have similar environmental behavior, toxicity, and exposure pathways to those of BPA, the prototype compound of this class. In view of the potential for occurrence and toxicity, determination of bisphenol analogues in indoor dust and evaluation of human exposure arising from the ingestion of dust are imperative to the assessment of risks and for the development of strategies to mitigate exposures. In this study, eight bisphenol analogues, including BPA, BPF, BPB, and BPS, were measured in 156 indoor dust samples collected from houses, offices, laboratories, and dormitories in the United States (U.S.), China, Japan, and Korea. The baseline concentrations of bisphenol analogues in indoor dust were established, and geographic distribution patterns were explored. Bisphenol exposures via dust ingestion for various age groups (infants, toddlers, children, teenagers, and adults) were estimated on the basis of measured concentrations. This is the first study to report the occurrence of bisphenol analogues other than BPA in indoor dust from the U.S. and three Asian countries.
nated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), phthalates, and bisphenols, among others. Mounting evidence suggests that EDCs interfere with the body’s endocrine system and adversely affect reproduction and development, neural network, and cardiovascular, metabolic, and immune systems in humans.1,2 Bisphenols are a group of chemicals with two hydroxyphenyl functionalities and include several analogues such as bisphenol A [BPA; 2,2-bis(4-hydroxyphenyl)propane], bisphenol B [BPB; 2,2-bis(4-hydroxyphenyl)butane], bisphenol F (BPF; 4,4′dihydroxydiphenylmethane), bisphenol AF [BPAF; 4,4′(hexafluoroisopropylidene)diphenol], and bisphenol S (BPS; 4,4′-sulfonyldiphenol). Bisphenols have been widely used as the base chemical in the manufacturing of polycarbonate plastics and the resin lining of food and beverage cans.3−6 Although studies have reported the ubiquitous occurrence of BPA in environmental and human samples,7−10 information on the occurrence of other bisphenol analogues is scarce. One study reported the occurrence of BPF in surface water, sewage, and sediments.11 BPF was reported to occur in soft drinks at a mean concentration of 0.180 μg/L.12 BPS has been reported to occur in canned foodstuffs at concentrations ranging from below the limit of quantitation (LOQ) to 175 ng/g.13 BPB has been found not only in canned foodstuffs but also in human serum from Italy at concentrations on the order of several tens of nanograms per gram.14,15 Diet is considered an important source of human exposure to contaminants such as PCBs, perfluorochemicals, phthalates, and BPA.16−19 In addition to diet, indoor air and indoor dust can be a significant source of human exposure to these contaminants. Elevated concentrations of BPA has been found in dust samples from daycare centers, homes, offices, and research laboratories, at concentrations on the order of several micrograms per gram; and ingestion of indoor dust has been demonstrated to be an exposure pathway to BPA in humans, especially children.20−23 The 2010 joint Food and Agriculture Organization (FAO) and World Health Organization (WHO) expert meeting estimated soil/dust ingestion at 0.0001−0.03 μg BPA/kg body weight (bw)/day for the general population.24 The contribution of dust ingestion to exposure to other bisphenols is not known.
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MATERIALS AND METHODS Chemicals. Bisphenol analogues, including BPA (purity: 97%), BPAF (97%), bisphenol AP [BPAP; 4,4′-(1phenylethylidene)bisphenol; 99%], BPF (98%), bisphenol P [BPP; 4,4′-(1,4-phenylenediisopropylidene)bisphenol; 99%], BPS (98%), and bisphenol Z [BPZ; 4,4′-cyclohexylidenebisphenol; 98%] were purchased from Sigma-Aldrich (St. Louis, 9139
dx.doi.org/10.1021/es302004w | Environ. Sci. Technol. 2012, 46, 9138−9145
Environmental Science & Technology
Article
Table 1. Elemental Composition and Ions Monitored for Several Bisphenol Analogues Analyzed in This Study target compounds
CAS no.
elemental composition
molecular weight
retention time (min)
MS/MS ions (m/z)
BPA BPAF BPAP BPB BPF BPP BPS BPZ
80−05−7 1478−61−1 1571−75−1 77−40−7 620−92−8 2167−51−3 80−09−1 843−55−0
C15H16O2 C15H10F6O2 C20H18O2 C16H18O2 C13H12O2 C24H26O2 C12H10O4S C18H20O2
228.29 336.23 290.36 242.32 200.23 346.46 250.27 268.35
19.1 20.5 20.9 20.2 17.2 22.6 13.3 21.2
227 > 212 335 > 265 289 > 274 241 > 212 199 > 93 345 > 330 249 > 108 267 > 173
Biosystems API 2000 electrospray triple quadrupole mass spectrometer (ESI-MS/MS; Applied Biosystems, Foster City, CA), coupled with an Agilent 1100 Series HPLC (Agilent Technologies Inc., Santa Clara, CA) equipped with a binary pump and an autosampler. An analytical column (Betasil C18, 100 × 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. The injection volume was 10 μL. The mobile phase was methanol and water at a flow rate of 0.3 mL/min with a gradient as follows: 0−2 min, 15% methanol; 2−5 min, 15−50% methanol; 5−8 min, 50% methanol; 8−20 min, 50−90% methanol; 20−21 min, 90−99% methanol; 21−25 min, 99% methanol; 25−30 min, 15% methanol. The negative ion multiple reaction monitoring (MRM) mode was used; the transitions of ions monitored are listed in Table 1. The MS/MS parameters were optimized by infusion of individual compounds into the mass spectrometer through a flow injection system (Supporting Information (SI) Table S1). Nitrogen was used as both a curtain and a collision gas. Quality Assurance and Quality Control (QA/QC). The extraction efficiency of bisphenols from dust samples was examined by performing a third extraction (after the first two extractions) with 3 mL solvent mixture of methanol and water (5:3, v/v) for 20 randomly selected samples. BPA was detected in the third extraction in 4 of 20 samples, at concentrations ranging from 0.13 to 0.57 ng/mL. In comparison with the high concentrations of BPA detected in these dust samples (ranging from 203 to 2035 ng/g), the residual BPA found in the third extraction was only 1.1 ± 0.6% (mean ± SD) of the total concentration. BPF was detected in the third extraction in only one sample (0.58 ng/mL), and the residual BPF found in the third extraction was 1.0% of the total concentration in the corresponding dust sample (1890 ng/g). No other bisphenols were detected in the third extraction. With each set of 20 samples, a procedural blank, a spiked blank (containing water in place of dust), a pair of matrix spike samples (50 ng of BPA and 20 ng of other individual bisphenols), and duplicate samples were analyzed. Trace levels of BPA, BPF, and BPS (approximately 0.01, 0.3, and 0.01 ng/mL, respectively) were found in procedural blanks in some batches, and background subtraction was performed in the quantification of concentration in samples. Recoveries of bisphenols in spiked blanks ranged from 89 ± 10% (mean ± SD) for BPAF to 109 ± 6% for BPS (SI Table S2). Recoveries of bisphenols in spiked matrices ranged from 51 ± 11% for BPZ to 137 ± 45% for BPS (SI Table S2). Duplicate analysis of randomly selected samples showed a coefficient variation of
