Infant exposure to polybrominated diphenyl ethers (PBDEs) via consumption of homemade baby food in Korea

Environmental Research 134 (2014) 396–401

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Infant exposure to polybrominated diphenyl ethers (PBDEs) via consumption of homemade baby food in Korea Yunsun Jeong a, Sunggyu Lee a, Sunmi Kim b, Sung-Deuk Choi c, Jeongim Park d, Hai-Joong Kim e, Jeong Jae Lee f, Gyuyeon Choi f, Sooran Choi g, Sungjoo Kim h, Su Young Kim i, Young Don Kim i, Geumjoon Cho e, Eunsook Suh f, Sung Koo Kim h, So-Hee Eun e, Soyong Eom j, Seunghyo Kim i, Gun-Ha Kim e, Won Chan Lee k, Kyungho Choi b, Sungkyoon Kim b, Hyo-Bang Moon a,n a

Department of Marine Sciences and Convergent Technology, Hanyang University, Ansan, Republic of Korea School of Public Health, Seoul National University, Seoul, Republic of Korea c School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea d College of Natural Sciences, Soonchunhyang University, Asan, Republic of Korea e College of Medicine, Korea University, Seoul, Republic of Korea f College of Medicine, Soonchunhyang University, Seoul, Republic of Korea g College of Medicine, Inha University, Incheon, Republic of Korea h College of Medicine, Hallym University, Seoul, Republic of Korea i College of Medicine, Jeju National University, Jeju, Republic of Korea j College of Medicine, Yonsei University, Seoul, Republic of Korea k National Fisheries Research and Development Institute, Busan, Republic of Korea b

art ic l e i nf o

a b s t r a c t

Article history: Received 31 May 2014 Received in revised form 17 July 2014 Accepted 18 August 2014 Available online 22 September 2014

Limited data are available on the residue levels of polybrominated diphenyl ethers (PBDEs) in baby food. In this study, 24 PBDE congeners were determined in 147 homemade baby food samples collected from 97 households for 6-, 9-, 12-, 15-, and from 24 to 27-month-old infant groups during the period of 2012– 2013. The concentrations of total PBDEs (ΣPBDE) ranged from 24.5 to 6000 (mean: 263) pg/g fresh weight, higher than those found in commercial formulae from the United States. The predominant congeners were BDEs 209 and 47, accounting for 92% of the ΣPBDE concentrations, reflected by high deca-BDE consumption in Korea. The residue levels and detection rates of BDE 47 in the baby food samples showed a gradual increasing trend with an increase in infant ages, due to changes in the food ingredients from hypoallergenic to greasy. The daily intakes of BDEs 47 and 209 via baby food consumption ranged from 0.04 to 0.58, 0.80 to 20.3, and 1.06 to 22.3 ng/kg body weight/day for 6-, 9, 12-, 15-, and 24–27-month-old infant groups, respectively; these intakes were lower than the oral reference doses proposed by the US EPA. Together with three exposure sources, baby food, breast milk and dust ingestion for 6-month-old infants, the daily intake of ΣPBDE was 25.5 ng/kg body weight/day, which was similar to the intake via baby food consumption only for over 24-month-old infants in our study. This indicates that baby food is an important exposure pathway of PBDEs for over 24-month-old infants. This is the first study regarding the occurrence and exposure assessment of PBDEs via homemade baby food. & 2014 Elsevier Inc. All rights reserved.

Keywords: Baby food BDE 209 BDE 47 Infant Daily intake Breast milk

1. Introduction Polybrominated diphenyl ethers (PBDEs) are representative brominated flame retardants (BFRs), which are used in a variety of consumer products such as textiles, electronic and electrical

n Corresponding author at: Department of Marine Sciences and Convergent Technology, Hanyang University, Ansan, Republic of Korea. Fax: þ 82 31 408 6255. E-mail address: [email protected] (H.-B. Moon).

http://dx.doi.org/10.1016/j.envres.2014.08.018 0013-9351/& 2014 Elsevier Inc. All rights reserved.

equipment, and other materials (La Guardia et al., 2006; Schecter et al., 2006). Commercially technical mixtures of PBDEs are classified into three degrees of bromination: penta-, octa-, and deca-BDEs. Penta- and octa-BDE technical mixtures were voluntarily withdrawn by manufacturers in the United States (US) and banned in the European Union (EU) since 2004. In 2009, the United Nations Environment Program (UNEP) nominated the penta- and octa-BDEs as emerging persistent organic pollutants (POPs) regulated by the Stockholm Convention. More recently, the use of deca-BDE was phased out in the EU and the US

Y. Jeong et al. / Environmental Research 134 (2014) 396–401

manufacturers announced plans to phase out deca-BDE in 2013 (US Environmental Protection Agency, 2010). However, many products containing PBDEs have been extensively used and commercialized as BFRs in many countries without regulation. Due to the persistence, bioaccumulation, and adverse health effects of PBDEs, these contaminants have received considerable concerns during the past two decades. Several epidemiological studies have reported that PBDE exposure elicits alternations of thyroid and reproductive hormones (Meeker et al., 2009; Chevrier et al., 2010; Johnson et al., 2013), developmental neurotoxicity (Roze et al., 2009; Herbstman et al., 2010), and lower birth weight and length (Chao et al., 2007). PBDEs were not produced in Korea, but were imported from other countries in order to support the demands of the growing electrical and electronic markets. The technical mixture of deca-BDE has been widely used and its consumption has accounted for a major proportion (25%) of the total BFR market in Korea (KISTI (Korea Institute of Science and Technology Information), 2002; Moon et al., 2007b). Previous studies have reported severe contamination by PBDEs, with dominance of BDE 209, in water, sediment, and sludge samples from Korea (Moon et al., 2007a, 2012; Lee et al., 2014). The primary exposure pathways of PBDEs for the general population are diet, dust ingestion and inhalation (Van Leeuwen et al., 2009; D’Hollander et al., 2010; Besis and Samara, 2012; Lee et al., 2013a). Several studies have suggested that dust ingestion is the major exposure route of PBDEs to humans (Johnson-Restrepo and Kannan, 2009; Harrad et al., 2010), whereas some studies have reported that meat and seafood are the significant sources of PBDEs (Jensen et al., 2001; Schecter et al., 2006; Lee et al., 2013a; Zhang et al., 2013). Therefore, the exposure status of PBDEs varies considerably between countries and between population groups within countries. In particular, certain subgroups of populations may have higher risks from exposure to PBDEs than the general population (Jones-Otazo et al., 2005; Lee et al., 2013a). Infants are simultaneously exposed to PBDEs through breast milk, house dust and diet such as baby food (Jones-Otazo et al., 2005). Many studies have focused on breast milk consumption as a major exposure pathway of PBDEs to infants (Jones-Otazo et al., 2005; Lunder et al., 2010; Lee et al., 2013b; Abdallah and Harrad, 2014). Korean women have traditionally used homemade baby food to supplement breast milk (KIHASA (Korea Institute for Health and Social Affairs), 2006). However, the importance of baby food consumption to PBDE exposure for infants has not been well characterized. Homemade baby food could be a major source of PBDEs exposure for Korean infants, because the breast milk consumption rate is lower for Korean infants than infants in North America and EU countries (WHO, 2001; KIHASA, 2006). A previous study reported that organochlorine pesticides (OCPs) such as chlordanes and heptachlor epoxide posed potential health risks from simultaneous exposures by breast milk and homemade baby food to Korean infants (Jeong et al., 2014). Therefore, it is essential to determine PBDEs in baby food and to accurately assess the PBDE exposure with other exposure pathways, such as breast milk and house dust. A few studies are available on the occurrence and exposure of PBDEs in infant formula used as baby food (Schecter et al., 2004, 2006; EFSA, 2011). Commercial infant formula are usually processed with dried food items such as vegetable and meat. However, the components of homemade baby food are dependent on food consumption patterns of individual household in Korea. To date, there was no report on PBDEs in homemade baby food. Therefore, the objectives of this study were to investigate the occurrence, concentrations and compositional profiles of PBDEs in homemade baby food and to assess the daily intake and potential health risks of these contaminants for Korean infants. In addition, the contribution of baby food to the total exposure of Korean infants to PBDEs was assessed with multiple sources of PBDEs such as breast milk and dust ingestion.

397

2. Materials and methods 2.1. Sample collection The homemade baby food samples (n¼ 147) were collected from participating mothers (n¼97) in the Children's Health and Environmental Chemicals in Korea Panel, or CHECK Panel (Kim et al., 2013; Lee et al., 2013b, 2013c). CHECK Panel is comprised of pregnant women-fetus pairs recruited from four cities since 2011 in Korea. In this study, the baby food samples were collected from Seoul, Pyeongchon, Ansan, and Jeju, which are representatives of residential (Seoul and Pyeongchon), industrial (Ansan), and rural (Jeju) regions in Korea, during the period from 2012 to 2013. The individual baby food items such as water, beverages, rice, vegetables, fruits, meat, and fish, were collected from participant mothers, with consideration of the actual weight of the ingredients in the baby food. The collected food items for each household were transported to the laboratory. All of the food items were pooled and homogenized with an ultra-disperser to obtain one sample from each household or subject group. The homogenized baby food samples were stored at  25 1C until analysis. The homemade baby food samples were classified as five subject groups according to infant age; (1) 6-month-old (n ¼21), (2) 9-month-old (n ¼29), (3) 12-month-old (n ¼37), (4) 15-month-old (n¼12), and (5) from 24 to 27-month-old (n¼ 48). 2.2. Standards and reagents Twenty-four PBDE congeners (IUPAC no.: BDEs 17, 28, 47, 49, 66, 71, 77, 85, 99, 100, 119, 126, 138, 153, 154, 156, 183, 184, 191, 196, 197, 206, 207, and 209; BDE-CVS-G, Wellington Laboratories, Guelph, ON, Canada) composed of tri- to deca-BDEs were determined in baby food samples. PCBs 103, 198, and 209, obtained from AccuStandard (New Haven, NJ, USA), were used as surrogate standards. The 13C-labelled PBDEs (BDEs 28, 47, 99, 153, 154, 183, 197, 207, and 209; MBDE-MXE) were used as internal standards, which were obtained from Wellington Laboratories. The ultratrace residue analysis grade dichloromethane (DCM) and hexane were supplied from J.T. Baker (Phillipsburg, NJ, USA). Nonane (Pesticide analysis grade) was supplied from Sigma-Aldrich (St. Louis, MO, USA). Anhydrous Na2SO4 (Pesticide analysis grade) and neutral silica gel were purchased from GL Sciences (Tokyo, Japan). 2.3. Chemical analysis Analyses of the PBDEs in the baby food samples were performed by methods described elsewhere (Moon et al., 2007a; Lee et al., 2013a). In brief, approximately 15–20 g of the baby food samples were homogenized with anhydrous Na2SO4 and then extracted with mixed solvents of DCM:hexane (3:1) using a Soxhlet apparatus for 16 h. Prior to extraction, 100 ng of the surrogate standards (PCBs 103, 198, and 209) were spiked into the samples. The extract was concentrated to 11 mL, and an aliquot (1 mL) was used for gravimetric determination of the lipid content. The remaining aliquot was spiked with internal standards of 13C-labelled PBDEs and then cleaned by a multi-layered silica gel column, containing 2% KOH silica-gel, 22% and 44% H2SO4 silica-gel and hexane washed silica-gel with 150 mL of 15% DCM in hexane. The eluted fractions were concentrated to 1 mL and were dissolved in 100 mL of nonane for instrumental analysis. Twenty-four PBDE congeners were measured using a high resolution gas chromatography interfaced with high resolution mass spectrometry (HRGC/HRMS; JMS 800D, JEOL, Tokyo, Japan). The PBDEs were quantified using an isotope dilution method, based on the relative response factors (RRF) of individual congeners of PBDEs. The HRMS was operated in electron ionization (EI) mode and the ions were monitored by selected ion monitoring. The PBDE congeners were separately quantified, ranging from tri- to hepta-BDEs and from octa- to deca-BDEs, using a DB-5MS (15 m length, 0.25 mm inner diameter, 0.1 μm film thickness; J&W Scientific, Palo Alto, CA, USA) with different oven temperature programs. Procedural blanks (n¼ 15) were processed for every 10 samples with real samples in order to check for background contamination of PBDEs. The procedural blanks did not contain quantifiable amounts of the target compounds, except for BDE 209 (which was present at approximately 0.1 ng/g). The solvents injected before and after the injection of the standards showed negligible contamination or carryover. The limit of quantification (LOQ) was calculated as 10 times the signal to noise ratio, which ranged from 0.1 to 0.5 pg/g fresh weight for tri- to hepta- BDEs, and from 5.0 to 10 pg/g fresh weight for octa- to deca-BDEs. The recoveries of the surrogate standards (PCBs 103, 198, and 209), spiked into all of the baby food samples before extraction, ranged from 85% to 92% (mean: 87%). The recoveries of the 13C-labelled BDEs 28, 47, 99, 153, 154, 183, 207, and 209 were 94 7 16% (average7 standard deviation), 87 7 15%, 90 717%, 887 19%, 897 23%, 867 21%, 887 23% and 867 27%, respectively. In order to assess the quality of the PBDE determination, the standard reference house dust materials (NIST, Gaithersburg, MD, USA, SRM 2585) were analyzed. The recoveries (n¼ 5) of the measured PBDE values for SRM 2585 ranged from 72% to 117%, with a mean value of 92%. The measured lipid contents in the homemade baby food samples were 0.6 7 0.8%, 1.1 71.3%, 0.9 7 1.1%, 1.4 7 1.6%, and 5.7 7 4.6% for 6-, 9-, 12-, 15-, and 24–27month-old infant groups, respectively. The overall lipid contents increased with an

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increase in the subject age groups, implying that the ingredients in the collected baby food changed from hypoallergenic to greasy with increase in age. 2.4. Calculation of PBDE intake via homemade baby food The daily intake of PBDEs via the consumption of homemade baby food was calculated by multiplying the consumption rate of baby food with the concentrations of PBDEs measured in this study. In this study, the body weight (bw) and consumption rates of the baby food for each subject group were measured in order to accurately assess the potential health risks associated with baby food consumption for Korean infants. The body weight and baby food consumption rate for each subject group were obtained from a questionnaire. The estimated body weights for each subject group were 8.53, 9.47, 9.98, 10.5, and 12.8 kg for 6-, 9-, 12-, 15-, and 24–27-month-old infant groups, respectively. The estimated consumption rates (g/ day) of homemade baby food in this study were 95.9, 161, 222, 310, and 700 g/day for 6-, 9-, 12-, 15-, and 24–27-month-old infant groups, respectively. Most of the homemade baby food samples contained rice with vegetables, fruits, meat, and fish, and were dependent on the infant ages. 2.5. Statistical analyses The total concentrations of the PBDEs (ΣPBDE; the sum of PBDE congeners detected) and individual PBDE congeners detected 450% in the baby food samples were used for statistical analyses. Undetected PBDE congeners were imputed with LOQ/sqrt2. Kolmogorov–Smirnoff and Shapiro–Wilk tests were conducted to assess the normality of the data. Because the concentrations of PBDEs were log-normally distributed within each subject group, the concentrations of individual congeners of PBDEs were transformed by the natural logarithm before statistical analyses. Analysis of variance (ANOVA) was used to determine significant differences in the concentrations of the PBDEs and the estimated daily intakes (EDIs) between the subject groups. The statistical significance was based on the level of p o 0.05. All of the statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) Version 18 for Windows (SPSS, Chicago, IL, USA).

3. Results and discussion 3.1. Occurrence and concentrations of PBDEs The occurrence and concentrations of PBDE congeners in the homemade baby food samples from Korea are summarized in Table 1. PBDEs were detected in approximately 90% of the baby food samples, indicating widespread contamination of homemade baby food by PBDEs. Among the 24 PBDE congeners analyzed, only 10 congeners were detected in all of the baby food samples. The detection rates of PBDE congeners were, in decreasing order: BDEs 47 (80%), 209 (59%), 99 (31%), and 28 (26%), which are major congeners of PBDEs detected in food samples from other studies (Schecter et al., 2004, 2006; EFSA, 2011). The other congeners of PBDEs such as BDEs 100, 207, 183, 154, 153, and 71, showed detection rates of less than 20% in all of the samples. The concentrations of ΣPBDE in the baby food samples ranged from 25 to 6000 (mean: 263) pg/g fresh weight. Considerable variation was found in the concentrations of PBDEs among the baby food samples, due to the diverse ingredients of homemade baby food samples depending on the age of subject group. We found no significant (p4 0.05) differences in the concentrations of PBDEs among the regions for homemade baby food samples. Among the PBDE congeners analyzed, BDE 209 showed the highest concentrations, ranging from o10 to 5940 pg/g fresh weight, with a mean value of 234 pg/g fresh weight. The concentrations of BDE 47 ranged from o 0.1 to 56 pg/g fresh weight, with a mean value of 5.9 pg/g fresh weight. Compared to other studies, the mean concentration (234 pg/g fresh weight) of BDE 209 in our study was similar to those measured in infant formula from European countries (130 pg/g fresh weight; EFSA, 2011). However, the mean concentration of BDE 47 (5.9 pg/g fresh weight) in our study was lower than those found in infant formula from European countries (210 pg/g fresh weight; EFSA, 2011). Infant formula from the US market showed lower ΣPBDE concentrations (30 pg/g fresh weight) than those in our study (Schecter et al., 2004, 2006).

The congener profiles of PBDEs detected in the homemade baby food samples are shown in Fig. 1. The major congeners of PBDEs in the baby food samples were BDEs 209 and 47. BDE 209 showed the highest contribution, with 60745% to the ΣPBDE concentrations, which is reflecting in the consumption pattern of PBDE technical mixtures in Korea. In Asia, the consumption of deca-BDE was estimated to be approximately 24,000 t in 2001 with high consumption (50%) in Korea (Moon et al., 2007a, 2007b). Previous studies showed the dominance of BDE 209 (495%) on the total PBDE concentrations in sediment, house dust, and sludge from Korea (Moon et al., 2007a, 2007b, 2012; Lee et al., 2013a, 2014). Therefore, Korean infants are exposed to BDE 209 associated with baby food consumption and dust ingestion. The next major congener was BDE 47, accounted for 32741% of the ΣPBDE concentrations. The other PBDE congeners such as BDEs 99, 183, 207, 100, and 28 showed low contributions in ΣPBDE concentrations. Similar results were found in commercial infant formula from other countries. Infant formula from the United States (US) was dominated by BDE 209 (Schecter et al., 2004). In Europe, the contribution of BDEs 47 and 209 were highest in commercial infant formula (EFSA, 2011).

3.2. Comparison of PBDEs in baby food among infant age groups The concentrations of BDE 47, BDE 209, and ΣPBDE were compared among each subject group (Fig. 2). The mean concentrations of ΣPBDE for each subject group were 94, 311, 184, 108, and 407 pg/g fresh weight for 6-, 9-, 12-, 15-, and 24–27-month-old infant groups, respectively. The highest concentration of ΣPBDE (6000 pg/g fresh weight) was found in the baby food for 24–27-month-old infants and the lowest ΣPBDE (24.5 pg/g fresh weight) was found for 6-month-old infants. A similar pattern of residue levels was found for organochlorines (OCs), such as PCBs and DDTs, in the same sample set from a previous study (Jeong et al., 2014). Our findings seem to be due to the difference in the ingredients in baby food with an increase in the infant ages. In fact, increasing lipid contents were found in our samples with an increase in the age of the subject group. The lipid contents in the baby food for 24–27-month-old infants (mean: 5.7%) were approximately 10 times higher than those measured for 6-monthold infants (mean: 0.6%). According to a report by the Korea Health Promotion Foundation (KHPF), baby food for 6-month-old infants consists of hypoallergenic foods such as rice, vegetable and fruit, but 15-month-old and older infants consume greasy food like adults (KHPF, 2011; Table S1). It should be noted that over 15-month-old infants are a biologically sensitive group for the exposure to toxic chemicals due to lower detoxifying potential and body burden than adults (Dourson et al., 2004; Pandelova et al., 2011; Piccinelli et al., 2010). Table 1 Concentrations (pg/g fresh weight) and detection rates (%) of the PBDEs in the homemade baby food samples collected in Korea between 2012 and 2013.

BDE 28 BDE 47 BDE 71 BDE 99 BDE 100 BDE 153 BDE 154 BDE 183 BDE 207 BDE 209 ΣPBDEb a b

Mean 7 SDa

50th

95th

Range

Detection rate (%)

0.55 7 1.3 5.9 7 9.8 0.107 0.21 1.9 7 5.1 0.54 7 2.3 0.51 71.2 0.56 7 1.6 0.59 7 1.3 5.3 7 12 234 7 697 263 7 702

0.07 2.1 0.07 0.07 0.07 0.35 0.35 0.35 3.5 10 45

3.3 22 0.07 11 1.6 0.35 0.35 0.35 3.5 1120 1160

o0.1–8.3 o0.1–55 o0.1–2.5 o0.1–34 o0.1–19 o 0.5–14 o 0.5–18 o 0.5–11 o 5.0–134 o 10.0–5940 24.5–6000

26 80 5 31 16 4 5 7 12 59 89

SD ¼ standard deviation. Sum of PBDE congeners detected.

Y. Jeong et al. / Environmental Research 134 (2014) 396–401

The overall concentrations of BDE 47 in the homemade baby food samples showed a gradual increasing trend with an increase in the infant age. In particular, the concentrations of BDE 47 in the baby food for 24–27-month-old infants were significantly higher (ANOVA, p o0.05) than those found for the other subject groups. As mentioned above, the results could have been influenced by the changes from rice/vegetable to greasy foods in the ingredients with an older infant age. BDE 47 is a predominant congener in greasy food such as seafood, meat, and dairy products (Schecter et al., 2004, 2006; EFSA, 2011). However, no significant differences were found in the concentrations of BDE 209 and ΣPBDE, despite the highest levels of PBDEs in the oldest infant group. The detection rates of BDEs 47 and 209 in the baby food samples in the older infant ages support our findings (Fig. 3). The detection rates of BDE 47 gradually increased with an increase in the age of the subject group, whereas BDE 209 had no increasing trend for the detection rates. Our results imply that BDE 209 has diverse contamination sources for homemade baby food.

3.3. Estimation of the daily intake of PBDEs and health risk assessment The estimated daily intakes (EDIs) of BDE 47, BDE 209, and

ΣPBDE for 6, 9, 12, 15, and 24–27-month-old infant groups via the

Relative contribution (%)

100 80 60 40

399

consumption of homemade baby food are summarized in Table 2. The EDIs using the average and 95th percentile concentrations of PBDEs represent the average and high exposure group for the infant populations in our study, respectively. For the average infant group, the EDIs of BDE 47, BDE 209 and ΣPBDE for all of the subject groups ranged from 0.04 to 0.58, 0.80 to 20.3, and 1.06 to 22.3 ng/ kg bw/day, respectively. For the high exposure group, the EDIs of BDE 47, BDE 209, and ΣPBDE ranged from 0.23 to 1.39, 3.80 to 75.7, and 4.00 to 77.0 ng/kg bw/day, respectively. The EDIs of PBDEs for the high exposure group were 3–8 times higher than those for the average exposure group. The daily intakes of PBDEs via baby food consumption in this study were similar to those reported for ∑PCB and ∑OCP from our previous study using the same sample set (Jeong et al., 2014). The EDIs of BDE 209 for all of the subject groups contributed over 76% to the EDIs of ΣPBDE. In particular, the contribution of BDE 209 for the high exposure group was 490% of the ΣPBDE exposure. This result suggests that BDE 209 is a major PBDE congener for infant exposure via baby food consumption in Korea. The EDIs of BDEs 47, BDE 209, and ΣPBDE for the 24–27-monthold infants were an order of magnitude higher than the EDIs found for the 6- to 15-month-old infants, associated with a change in the ingredients in the baby food. Our results indicate that Korean infants have higher PBDE exposure via the consumption of baby food with an increase in age. In the present study, the EDIs of BDEs 47 and 209 were compared to the oral reference dose (RfD) proposed by the US EPA (US EPA, 2008), to assess the infant health risk by the PBDE exposure associated with the consumption of homemade baby food. The respective RfDs for BDEs 47 and 209 are proposed to be 100 and 7000 ng/kg bw/day, which were two orders of magnitudes higher than the EDIs of BDEs 47 and 209 found in our study. These results imply that the PBDE exposure via the consumption of baby food is safe for Korean infants. 3.4. Simultaneous exposure assessment of PBDEs with multiple sources

20

9 20

7

3

D B

B

D

E

E

20

15

E D B

B

D

E

18

4

3

0

15

B

D

E

10

99

E

E

D

D B

B

47

E B

D

E

28 E

D B

D B

71

0

Fig. 1. Relative contribution of PBDE congeners detected in homemade baby food samples from Korea. Vertical lines represent standard deviations.

10

1

0.1

0.01

1000

100

10

1

10000

Concentration (pg/g fresh weight)

100

10000

Concentration (pg/g fresh weight)

Concentration (pg/g fresh weight)

1000

Infants are exposed to PBDEs from multiple sources including breast milk, dust ingestion, and diet, such as baby food (JonesOtazo et al., 2005). Therefore, the simultaneous consideration of multiple sources of PBDE exposure is essential to accurately assess the contribution from each source and to establish efficient

1000

100

10

1

6-month-old 9-month-old 12-month-old 15-month-old 24 to 27-month-old

Fig. 2. Comparison of concentrations of (a) BDE 47, (b) BDE 209, and (c) total PBDEs in homemade baby food samples for the infant subject groups. The box plot represents the 10th, 25th, 50th and 90th percentiles with error bars. The circles are the 5th percentile (lower) and 95th percentile (upper). The arithmetic mean concentrations are given as red bars. *Significant differences at p o0.05. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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Y. Jeong et al. / Environmental Research 134 (2014) 396–401

are required to investigate additional sources of PBDE exposure, such as inhalation and contact with products containing PBDEs, for more accurate exposure estimation.

100

Detection rate (%)

80

BDE 47 BDE 209

60

4. Conclusions

40

20

0 6

9

12

15

24 to 27

Infant age (month) Fig. 3. Detection rates (%) of BDEs 47 and 209 in homemade baby food samples for the infant subject groups.

Table 2 Estimated daily intakes (EDIs, ng/kg body weight/day) of BDE 47, BDE 209, and ΣPBDE and its contribution to the total EDIs via the consumption of homemade baby food in Korea.

BDE 47 (% contribution) Average 6-month-old 9-month-old 12-month-old 15-month-old 24–27-month— old 95th percentile 6-month-old 9-month-old 12-month-old 15-month-old 24–27-month— old a

0.04 0.06 0.09 0.06

(3.8) (1.1) (2.2) (1.9)

BDE 209 (% contribution)

0.80 4.88 3.45 2.52

(76) (92) (85) (81)

ΣPBDEa

Acknowledgments 1.06 5.28 4.08 3.10

0.58 (2.7)

20.3 (92)

22.3

0.23 0.20 0.54 0.24

3.80 47.9 12.4 11.0

4.00 48.3 12.8 11.7

(5.4) (0.4) (3.9) (2.0)

1.39 (1.7)

(89) (99) (91) (93)

75.7 (95)

This is the first study to investigate the current levels and exposure assessment of PBDEs in homemade baby food samples. PBDEs were detected in approximately 90% of the samples. The concentrations of PBDEs detected were higher than those found in commercial formula from the US. BDEs 47 and 209 were the major congeners, reflected by the high consumption of the deca-BDE mixture in Korea. The gradual increasing trends in the concentrations and detection rates of BDE 47 were found for the subject groups, due to changes in the food ingredients over older infant age. The daily intakes of PBDEs estimated in our study were lower than the RfD proposed by the US EPA. Considering multiple exposure sources of PBDEs for 6-month-old infants, the daily intake of ΣPBDE was similar to the EDI via only baby food consumption for over 24 month-old infants. This implies the importance of baby food as an important source of PBDEs for over 24-month-old infants.

We would like to express our gratitude to all participating mothers in the CHECK (Children's Health and Environmental Chemicals in Korea) Panel for their great efforts in collecting homemade baby food samples. This study was supported by the Korea Food and Drug Administration (KFDA, 12162KFDA732) and the Ministry of Environment of Korea as the Environmental Health Action Program (ARQ201303083). YS Jeong, SG Lee and SM Kim are supported by BK21 Plus program of National Research Foundation.

77.0

Sum of PBDE congeners detected.

strategies for reducing PBDE exposure for infants. Considering the simultaneous exposure pathways of PBDEs to infants, the EDIs of ΣPBDE for 6-month-old infants were selected for comparison. From our previous studies, the EDIs of ΣPBDE for breast milk consumption and dust ingestion were 14.1 ng/kg bw/day and 10.3 ng/kg bw/day, respectively (Lee et al., 2013a, 2013b), which were an order of magnitude higher than the EDI of ΣPBDE (1.06 ng/kg bw/day) via baby food consumption for 6-month-old infants in the present study. Together with the three exposure pathways of PBDEs to Korean infants, the total EDI of ΣPBDE was 25.5 ng/kg bw/day. The relative contribution of the total PBDE exposure was 55%, 41%, and 4.0% for breast milk, dust and baby food, respectively. To date, a few studies have performed on exposure assessment of PBDEs with multiple exposure pathways to infants. Johnson-Restrepo and Kannan (2009) reported that the relative contribution of the total PBDE exposure to the US infants is 91%, 7.8%, and 1.2% for breast milk, dust and food, respectively. Wilford et al. (2005) reported that the relative contribution of the total PBDE exposure to the Canadian child (6 months–2 years) is 70%, 30% and 0.07% for dust, food and air, respectively. In the present study, the EDI of ΣPBDE via baby food consumption was 22.3 ng/kg bw/day for 24–27-month-old infants, which is similar to total EDIs (25.5 ng/kg bw/day) of ΣPBDE from the three exposure pathways for 6-month-old infants. Our results suggest that baby food is an important exposure pathway for PBDEs for over 24-month-old infants. Further studies

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