Article pubs.acs.org/est
Occurrence and Human Exposure of p‑Hydroxybenzoic Acid Esters (Parabens), Bisphenol A Diglycidyl Ether (BADGE), and Their Hydrolysis Products in Indoor Dust from the United States and Three East Asian Countries Lei Wang,†,‡ Chunyang Liao,† Fang Liu,† Qian Wu,† Ying Guo,† Hyo-Bang Moon,§ Haruhiko Nakata,∥ 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 12210-0509, United States ‡ Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, and Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China § Department of Environmental Marine Sciences, College of Science and Technology, Hanyang University, Ansan 426-791, South Korea ∥ Graduate School of Science & 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: p-Hydroxybenzoic acid esters (parabens) and bisphenol A diglycidyl ether (BADGE) are widely present in personal care products, food packages, and material coatings. Nevertheless, little is known about the occurrence of these compounds in indoor dust. In this study, we collected 158 indoor dust samples from the U.S., China, Korea, and Japan and determined the concentrations of 11 target chemicals, viz., six parabens and their common hydrolysis product, 4-hydroxybenzoic acid (4-HB), as well as BADGE and its three hydrolysis products (BADGE·H2O, BADGE·2H2O, and BADGE·HCl·H2O). All of the target compounds were found in dust samples from four countries. Concentrations of sum of six parabens in dust were on the order of several hundred to several thousands of nanogram per gram. Geometric mean concentrations of BADGEs in dust ranged from 1300 to 2890 ng/g among four countries. Methyl paraben (MeP), propyl paraben (PrP), BADGE·2H2O, and BADGE·HCl·H2O were the predominant compounds found in dust samples. This is the first report of BADGE and its hydrolysis products (BADGEs) in indoor dust samples and of parabens in indoor dust from Asian countries. On the basis of the measured concentrations of target chemicals, we estimated the daily intake (EDI) via dust ingestion. The EDIs of parabens via dust ingestion were 5−10 times higher in children than in adults. Among the four countries studied, the EDIs of parabens (5.4 ng/kg-bw/day) and BADGEs (6.5 ng/kg-bw/day) through dust ingestion were the highest for children in Korea and Japan.
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INTRODUCTION Reports of the endocrine-disrupting potential of environmental chemicals continue to increase.1,2 Although some chemicals have been regulated due to their endocrine-disrupting potential, many endocrine-disrupting chemicals (EDCs) are still widely used in a variety of consumer products. There has been considerable interest in the assessment of the doses of human exposure to EDCs and associated health outcomes. Human exposure from the indoor environment is particularly important, as people spend most of their time indoors.3 Because many EDCs are present in household products as additives (e.g., plastics, cosmetics, paints), contamination of the indoor environment with these compounds is inevitable. © 2012 American Chemical Society
Bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), phthalic acid diesters (phthalates), alkyl phenols, and halogenated phenols have been reported to occur in many household commodities including personal care products.4,5 Human exposure to PBDEs, phthalates, and phenolic EDCs has been widely studied.6−10 Nevertheless, little is known about the exposures of other ether and ester compounds such as parabens and BADGE. Received: Revised: Accepted: Published: 11584
August 29, 2012 September 26, 2012 October 1, 2012 October 1, 2012 dx.doi.org/10.1021/es303516u | Environ. Sci. Technol. 2012, 46, 11584−11593
Environmental Science & Technology
Article
Table 1. Target Analytes (Parabens and Bisphenol A Diglycidyl Ether Derivatives) and Selected Physicochemical Properties
a
Predicted data cited from chemspider.com, which is generated using the US Environmental Protection Agency’s EPISuite, (KOWWIN v1.67 estimate). bPredicted data cited from chemspider.com, which is generated using the US Environmental Protection Agency’s EPISuite, [HENRYWIN v3.10] (25 °C), with a unit of atm-m3/mol.
Additives in 1974.13 Although the carcinogenicity of parabens is still debated,14,15 the endocrine-disrupting activities of these compounds have been widely reported in in vitro and in vivo tests.16−24 Denmark’s Environmental Ministry announced a ban on the use of two parabens, PrP and butyl paraben (BuP), in children’s products.12
As the most commonly used preservatives, p-hydroxybenzoic acid esters (i.e., parabens) are added to foods, cosmetics, and pharmaceuticals.11,12 An acceptable daily intake (ADI) in the range of 0−10 mg/kg-bw/day was suggested for methyl paraben (MeP), ethyl paraben (EtP), and propyl paraben (PrP) by the Joint FAO/WHO Expert Committee on Food 11585
dx.doi.org/10.1021/es303516u | Environ. Sci. Technol. 2012, 46, 11584−11593
Environmental Science & Technology
Article
Analytical standards of BADGE analogues, including BADGE (≥95%), BADGE·H2O (≥95%), BADGE·HCl·H2O (≥95%), BADGE·2H2O (≥97%), and BPA (97%), were purchased from Sigma-Aldrich (St. Louis, MO). The molecular structures and selected physiochemical properties of the target analytes are shown in Table 1. 13C-isotopically labeled 2-hydroxy-4methoxybenzophenone ( 13 C 12 −BP-3) (99%), 13 C 6 -MeP (99%), 13C6−BuP (99%), and 13C12-labeled BPA (99%) were purchased from Cambridge Isotope Laboratories (Andover, MA). Formic acid (98.2%) and methanol (HPLC grade) were purchased from Sigma-Aldrich and Mallinckrodt Baker (Phillipsburg, NJ), respectively. Milli-Q water was prepared using an ultrapure water system (Barnstead International, Dubuque, IA). The stock solutions of target analytes and internal standards were prepared at 1 mg/mL in methanol and stored at −20 °C. Sample Collection. Between 2006 and 2012, 158 dust samples were collected from 13 cities in four countries, including Albany (U.S., 2006 and 2010, n = 40), Beijing, Jinan, Guangzhou, Shanghai, Qiqihaer, and Urumchi (China, 2010, n = 55), Ansan and Anyang (Korea, 2012, n = 41), and Kumamoto, Nagasaki, Fukuoka, Saitama, and Saga (Japan, 2012, n = 22). Frequently used rooms of houses, apartments, offices, and laboratories were selected, and floor dust was collected using a vacuum cleaner from all locations, except for samples from China, which were collected by sweeping the floor directly. Before extraction, dust samples were sieved and homogenized by a 2 mm sieve. Sample Preparation. Dust samples were extracted by solid−liquid extraction and then by a solid phase extraction (SPE) method, as described in a previous study with minor modifications.41 In brief, 50−100 mg of dust were accurately weighed and spiked with 13C6-MeP (10 ng), 13C6−BuP (10 ng), 13C12−BP-3 (10 ng), and 13C12−BPA (20 ng). The spiked dust samples were equilibrated for 30 min at room temperature, and 5 mL of methanol/Milli-Q water mixture (5:3, v/v) were added for extraction. After being shaken in an oscillator shaker for 60 min (Eberbach Corp., Ann Arbor, MI), the mixture was centrifuged at 4500 × g for 5 min (Eppendorf Centrifuge 5804, Hamburg, Germany). The supernatant was transferred into a glass tube. The extraction was repeated with an additional 3 mL of methanol/Milli-Q water mixture. The combined extracts were concentrated to ∼4 mL under a gentle nitrogen stream and then diluted to 10 mL with Milli-Q water that contained 0.2% formic acid (pH 2.5). The extract was purified by passage through Oasis MCX cartridges (60 mg/3 cm3; Waters, Milford, MA). The cartridge was conditioned with 5 mL of methanol and then with 5 mL of Milli-Q water. The diluted sample extract (10 mL) was loaded, followed by passage of 15 mL of methanol/Milli-Q water (20:80, v/v) and 5 mL of Milli-Q water. After drying the cartridge by a gentle nitrogen stream, target analytes were eluted with 5 mL of methanol. The eluate was concentrated to 1 mL under a gentle nitrogen stream and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chemical Analysis. Separation and detection of target analytes were accomplished with an Agilent 1100 Series HPLC (Agilent Technologies Inc., Santa Clara, CA), interfaced with an Applied Biosystems API 3200 electrospray triple quadrupole mass spectrometer (ESI-MS/MS; Applied Biosystems, Foster City, CA). Ten microliters of the sample were injected onto an analytical column (Betasil C18, 100 × 2.1 mm column; Thermo Electron Corporation, Waltham, MA), which was connected to
Bisphenol A diglycidyl ether (BADGE) is a building block of epoxy resins that coat food and beverage cans and is used as a monomer in the production of epoxy-based polymers as well as an additive for the elimination of surplus hydrochloric acid in polyvinyl chloride (PVC) organosol production. BADGE is present in many canned foods and is absorbed through the gastrointestinal tract.25 Therefore, a migration limit of 1 mg/kg for BADGE and its hydrolytic and chlorinated derivatives (collectively referred to as BADGEs in this study) including bisphenol A (2,3-dihydroxypropyl) glycidyl ether (BADGE·H2O), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether (BADGE·HCl·H2O), and bisphenol A bis (2,3dihydroxypropyl) ether (BADGE·2H2O), has been set by the European Commission for food contact applications.26,27 Cytotoxic and genotoxic effects of BADGE and its hydrolysis and chlorohydrin products have been reported.26,28 BADGE·2H2O, a hydrolysis product of BADGE, was shown to exhibit estrogenic activity, even greater than that of BPA.29 Conspicuous antagonistic activity for androgen receptors also was reported for BADGE·2H2O.30 BADGE can form DNA adducts and result in teratogenic and mutagenic effects.31 Developmental toxicity of BADGE in male rats32 and reproductive effects of BADGE·2H2O in prenatal mice29,33 also have been reported. A ban on or regulation of the use of BPA, a popular EDC, in several countries will result in an indirect regulation of BADGE, as BPA in canned food is believed to be released from BADGE-based epoxy resin coating.34 Although the occurrence of parabens and BADGEs in foodstuffs, pharmaceuticals, and cosmetics,10−13,27,34−37 and the occurrence of parabens in surface water and wastewater treatment plants38 have been reported earlier, studies on the occurrence of these two classes of compounds in indoor dust are scant. Parabens are semivolatile compounds with Henry’s law constants that range from 2.92 × 10−10 to 1.98 × 10−8 atm·m3/mol (Table 1). Therefore, parabens are expected to be adsorbed on the surface of indoor dust after they are released into air. For example, maximum concentration of MeP in indoor air was reported to be ∼20 ng/m3.7 BADGE is present in epoxy resins that are used in paints, varnishes, and furniture coatings26 and can contribute to the contamination of indoor dust. Degradation or transformation of parabens and BADGE in indoor dust is unknown, although the occurrence of hydrolysis products of these compounds in aquatic environments has been reported.37,39,40 In this study, we determined the concentrations of six currently used parabens (i.e., MeP, EtP, PrP, BuP, benzyl paraben (BzP), heptyl paraben (HepP)) and their common hydrolysis product, 4-hydroxybenzoic acid (4-HB), as well as BADGE and its hydrolysis products, BADGE·H2O, BADGE·HCl·H2O, and BADGE·2H2O, in 158 indoor dust samples collected from the U.S., China, Korea, and Japan. The objectives of the study were to (i) reveal differences in concentrations and profiles of parabens and BADGE as well as their hydrolysis products in indoor dust collected from the U.S., China, Japan, and Korea; (ii) establish correlations between the target compounds; and (iii) assess human exposure doses of these compounds through the ingestion of indoor dust.
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MATERIALS AND METHODS Chemicals. Standard solutions of paraben analogues, including MeP, EtP, PrP, BuP, BzP, HepP, and 4-HB, were purchased from AccuStandard, Inc. (New Haven, CT). 11586
dx.doi.org/10.1021/es303516u | Environ. Sci. Technol. 2012, 46, 11584−11593
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