Residues of polybrominated diphenyl ethers in honeys from different geographic regions

Article abstract of DOI:10.1021/jf904490g

Polybrominated diphenyl ethers (PBDEs) are a class of widely used flame-retardants. Fifty honey samples labeled as being from different countries and regions were analyzed for 27 PBDE congeners. The concentrations of the 26 PBDEs, excluding BDE-209, ranged from 300 to 10,550 pg/g while the concentrations of BDE-209 ranged from nondetected to 9,260 pg/g. The honey samples labeled as originating In developed countries generally displayed higher concentrations of the total 27 PBDEs than those labeled as being from developing countries. Concentrations of 26 PBDEs ranged from 2,720 to 10,550 pg/g in honeys originating in developed countries and ranged from 1,030 to 3,470 pg/g in those from developing countries. BDE-209 was a dominant PBDE congener in all honey samples, on average accounting for 16% and 65% of the total 27 PBDEs in honeys from developed and developing countries, respectively. Honeys originating in developing countries, however, showed much higher BDE-209 levels and higher ratios of BDE-209 relative to the other PBDE congeners. In addition, some highly brominated PBDE congeners such as BDE196, -197, -206, and -207 showed elevated concentrations in honeys from developing countries. The findings were in agreement with the long, heavy historical uses of PBDE products in developed countries and the current, heavy uses of BDE-209 in developing countries. When BDE-209 was fortified in honey and incubated in the dark for four weeks at 25 or 60 °C, BDE-153, -183, -206, and -207 were detected as debromination products of BDE-209. Less brominated congeners in honeys may primarily come from the environment. Debromination of BDE-209 is also a source of less brominated congeners in honeys. The detection of PBDEs in honeys suggests that human exposure to PBDEs occurs as a result of honey consumption. 2010 American Chemical Society.

Full text of DOI:10.1021/jf904490g

J. Agric. Food Chem. 2010, 58, 3495–3501 3495
DOI:10.1021/jf904490g
Residues of Polybrominated Diphenyl Ethers in Honeys from
Different Geographic Regions
†
‡
§
,†
JUN
W
ANG, MICHAEL M. KLIKS, SOOJIN
J
UN
,
AND
Q
ING X. L *
I
†
§
Department of Molecular Biosciences and Bioengineering and Department of Human Nutrition, Food
and Animal Sciences, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, Hawaii 96822, and
‡
CTS Foundation, 3081G Paty Drive, Honolulu, Hawaii 96822
Polybrominated diphenyl ethers (PBDEs) are a class of widely used flame-retardants. Fifty honey
samples labeled as being from different countries and regions were analyzed for 27 PBDE
congeners. The concentrations of the 26 PBDEs, excluding BDE-209, ranged from 300 to 10,550
pg/g while the concentrations of BDE-209 ranged from nondetected to 9,260 pg/g. The honey
samples labeled as originating in developed countries generally displayed higher concentrations of
the total 27 PBDEs than those labeled as being from developing countries. Concentrations of 26
PBDEs ranged from 2,720 to 10,550 pg/g in honeys originating in developed countries and ranged
from 1,030 to 3,470 pg/g in those from developing countries. BDE-209 was a dominant PBDE
congener in all honey samples, on average accounting for 16% and 65% of the total 27 PBDEs in
honeys from developed and developing countries, respectively. Honeys originating in developing
countries, however, showed much higher BDE-209 levels and higher ratios of BDE-209 relative to
the other PBDE congeners. In addition, some highly brominated PBDE congeners such as BDE-
1
96, -197, -206, and -207 showed elevated concentrations in honeys from developing countries. The
findings were in agreement with the long, heavy historical uses of PBDE products in developed
countries and the current, heavy uses of BDE-209 in developing countries. When BDE-209 was
fortified in honey and incubated in the dark for four weeks at 25 or 60 °C, BDE-153, -183, -206, and
-
207 were detected as debromination products of BDE-209. Less brominated congeners in honeys
may primarily come from the environment. Debromination of BDE-209 is also a source of less
brominated congeners in honeys. The detection of PBDEs in honeys suggests that human exposure
to PBDEs occurs as a result of honey consumption.
KEYWORDS: Honey; polybrominated diphenyl ethers (PBDEs); food contamination; food safety
INTRODUCTION
threat to human health. PBDEs have been detected in human fat
tissues, blood, and breast milk (10). PBDE concentrations in the
environment and humans have increased rapidly in the past two
decades (11). The main route of exposure to PBDEs in the general
human population is through consumption of PBDE-contami-
nated food (12) and inhalation of vapor-phase chemicals in
contaminated indoor environments (13). PBDE-contaminated
foodincludesfish, dairy products, meat, eggs, and vegetables(14).
Dietary exposure is a very important route of exposure to
PBDEs (15).
Polybrominated diphenyl ethers (PBDEs) are used extensively
as flame retardants. Because of large production volumes, wide-
spread usage, and their persistence, PBDEs are now widespread
in the environment (1-3). The most common commercial PBDE
products worldwideare the penta-, octa- and deca-BDEmixtures.
The total world PBDE production was approximately 67,000 t in
2001 (4), of which deca-BDE mixtures accounted for 75% of the
total PBDE production (3). The commercial deca-BDE product
consists mainly (>95%) of the deca-congener (BDE-209) (5).
Previous reports have shown that PBDEs can enter the ambient
environment during production, use, disposal, and recycling
processes (6). PBDEs have been detected in virtually all environ-
mental media such as air, water, sediment, soil and plants (1-3,7,8).
PBDE contamination has become an emerging environmental
concern in recent years, which is attracting attention from the public
and environmental community.
PBDE residues in various foods have been documented. For
example, market basket surveys were performed for the content
of PBDEs in food items in Europe and North America (1,9,16,17).
The main PBDE congeners included BDE-47, -99, -100, -153, and -
2
09 in fish, meat, dairy products, vegetables, and other food items.
BDE-47 was the most dominant, and its concentration was
-46000, 3-740, 6-240, 4-120, and nd-90 pg/g wet weight
ww), respectively (9, 16, 17). Due to highly bioaccumulative
5
(
PBDEs can enter into the food chain via bioaccumulation in
fats or nonfatty products (9) and, thus, may present a potential
potential of PBDEs, fish is believed to be the main contributor of
PBDEs to human exposure (18,19) and thus it has been analyzed to
a greater extent than other food groups. The mean reported total
PBDE content ( PBDE) in fish was approximately 4200 pg/g ww
*
Corresponding author. Tel: 808-956-2011. Fax: 808- 956-3542.
P
E-mail: qingl@hawaii.edu.
©
2010 American Chemical Society
Published on Web 02/25/2010
pubs.acs.org/JAFC

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496 J. Agric. Food Chem., Vol. 58, No. 6, 2010
Wang et al.
Table 1. Geographical Origin Information of the 50 Honey Samples
country no. of samples location
P
while the median of the reported PBDE was 1100 pg/g ww
worldwide (18). High concentrations of PBDEs were found in fatty
products such as butter, fats and oils ( PBDE, 119-569 pg/g
ww) (16, 20, 21). Solid milk products like cheese also contained
relatively high amounts of PBDEs (18-34 pg/g ww), while liquid
P
Developed Countries
milk products contained very low concentrations of PBDEs (0.8
pg/g ww) (22). Concentrations of
USA
13
California, Kansas, Maryland, Virginia,
Washington, Wisconsin, North Dakota
P
PBDEs in fast food and
U.K.
Canada
Japan
3
2
3
Kent
Ontario
Tokyo
beverages were found to be 39-52 and 76 pg/g ww, respectively,
in Europe and North America (17,23). There have been no studies
of PBDEs in honey although honey is one of the most popular
foods in the world. Honey is often consumed by children and elderly
and ill people, particularly in developing countries. Therefore,
honey should be free of any chemical contamination and be safe
for human consumption.
Honeybees travel long distances and are likely exposed to
PBDEs deposited on plants and vegetations via atmospheric
transfer. Honey, therefore, may contain PBDE residues that
would correlate with the PBDE usages and pollution status in a
particular region. The objectives of this study were to determine
residual levels, compositions and distribution of PBDEs in honey
samples from different geographic regions, and to investigate
their possible pollution sources.
Developing Countries
China
India
2
2
2
2
2
2
2
1
North Eastern region
New Delhi
Thailand
Indonesia
Vietnam
Bhutan
Mexico
Argentina
North Thailand
Jakarta
South region
Bhumtang
Mexico City
Buenos Aires
Background Regions
USA
USA
10
2
Oahu and the Big Island, Hawaii
Central region, Alaska
West coast
MATERIALS AND METHODS
New Zealand
2
Sample Collection. Fifty honey samples were purchased directly from
the retail stores or mailed from different regions worldwide. These honeys
were labeled with the geographic regions and origin of the country
triplicate samples. After four weeks, two groups of the honey samples
were extracted, cleaned up and fractionated according to the aforemen-
tioned method.
(Table 1). They were grouped into developed and developing countries
Instrumental Analysis. PBDEs were analyzed on a Varian 3800 gas
chromatograph (GC) connected with a electron capture detector (ECD)
and Saturn 2000 ion trap mass spectrometer (ITMS) (Varian, Walnut
Creek, CA). An aliquot of 2.0 μL of sample was injected in splitless mode
with an AS8400 autosampler. The purge valve was activated 3 min after
the sample injection. The column flow rate was 2 mL/min of carrier gas
(helium). Temperatures of the injector and ion trap were 300 and 250 °C,
respectively. A 30 m DB-5MS capillary column (30 m  0.25 mm i.d., 0.25
μm film thickness) was used for the separation of BDE-3, -7, -15, -17, -28,
based on the current approximate economic status of the countries. For
discussion purposes, New Zealand, Hawaii and Alaska were referred to as
background regions due to their geographical isolation and lower popula-
tions. All honey samples were stored at -20 °C until extraction and
analysis.
Sample Extraction, Cleanup and Fractionation. A mixture of
surrogate standards of
13
C12-BDE-3, -15, -28, -47, -99, -153, -154, and -183
was added to 20 g of blank honey samples for recovery studies. The
blank honey samples were two honey samples labeled as originating in
Hawaii, in which PBDEs were not detected (Figure 1). All commercial
honey samples and recovery samples (20 g) were mixed with a 3-fold
amount of anhydrous sodium sulfate, wrapped with a filter paper, and
placed in a 64 mL extraction cell. The remaining volume of the cell was
filled up with clean Ottawa sand (20-30 mesh). The sample cell was
loaded onto an accelerated solvent extractor (ASE) 200 system (Dionex,
Sunnyvale, CA). The extraction was performed with a mixture of equal
volumes of acetone and methylene chloride at a pressure of 1500 psi and
temperature of 100 °C for three static cycles, a flush volume of 60% of the
-
-
47, -49, -66, -71, -77, -85, -99, -100, -119, -126, -138, -153, -154, -156, -183,
184, and -191. The column temperature was started at 100 °C for 2 min
and increased to 250 at 10 °C/min, 265 at 1 °C/min, 300 at 20 °C/min and
then was held at 300 °C for 10 min. BDE-196, -197, -207, -206, and -209
were separated on a 15 m DB-5MS column (15 m  0.25 mm i.d., 0.25 μm
film thickness). The oven temperature was programmed from 150 to 300
°
C at a rate of 10 °C/min and then held at 300 °C for 10 min. The ITMS
was operated under the conditions previously described (24, 25). GC/
ITMS parameters were also the same as previously described (24, 25)
except that the precursor ion for BDE-196 and 197 and BDE-209 was 642.
Because highly brominated PBDEs show higher sensitivity on the ECD
than on the MS, GC/ECD was used to monitor BDE-209 degradation
in honey.
2
cell volume and a N purge time of 5 s. Each honey sample was extracted in
triplicate, and an equal weight mixture of anhydrous sodium sulfate and
Ottawa sand was extracted as the blank control.
After the extract was dried with 30 g of anhydrous sodium sulfate and
rinsed with hexane (3 mL), it was concentrated to approximately 3 mL by
using a rotary evaporator. The concentrated extract in hexane was cleaned
up on an 8 mm i.d. aluminum/silica column. The column was packed, from
the bottom to the top, with neutral alumina (6 cm, 3% deactivated),
neutral silica gel (10 cm, 3% deactivated), 50% sulfuric acid silica (10 cm),
and anhydrous sodium sulfate. The column was eluted with 30 mL of
methylene chloride and hexane (1:1, v/v) to yield the PBDE fraction. The
fraction was concentrated to 20 μL under a gentle stream of high purity
nitrogen after an aliquot of 20 μL of dodecane was added as trapping
Quality Control and Quality Assurance. All analytical procedures
were performed under quality assurance and quality control protocols.
PBDEs were not detected in the three blank controls. The limits of detection
(LODs) were determined as signals 3 times the background signals. Peaks
that were smaller than 3 times the signal-to-noise ratio were considered
nondetected. The LOD of individual PBDE congeners ranged from 1 to 10
pg/g for all PBDE congeners except for BDE-209 (Table 2). The LOD for
BDE-209 was 30 pg/g. Recoveries of the surrogate standards averaged
between 60% and 120% (Table 2). Reported values are recovery-corrected.
13
solvent. A known quantity of
C12-PBDE-139 was then added as an
internal standard prior to the chemical analysis.
RESULTS AND DISCUSSION
Degradation of BDE-209 in Honey. Solutions of freshly purchased
BDE-209 dissolved in acetone were added to aliquots of the same blank
honey sample used in recovery tests at a concentration of 20 ng/g. One
group of honey samples, fortified with BDE-209 standard, was allowed to
incubate at 60 °C in the dark in an oven for four weeks. The incubation
temperature was set at 60 °C because honey is often processed at between
Fifty honey samples labeled from different countries and
regions were analyzed for 27 PBDE congeners. The PBDE
congeners were detected in all honey samples except two honey
samples labeled from Hawaii. Table 3 shows the average con-
centrations and concentration ranges of the PBDEs in honey
samples grouped according to the labels as originating in devel-
oped and developing countries and background regions.
6
0 and 65 °C. Another group of the BDE-209 fortified honey samples was
placed at 25 °C in the dark in an oven for four weeks. Each group had

Article
J. Agric. Food Chem., Vol. 58, No. 6, 2010 3497
Figure 1. Typical GC/ITMS chromatograms of PBDEs ina standard mixture(50 ppb each congener) (A), chromatograms of extracts of a blank control honey
sample(B) andhoneysamplesfrom adeveloped country(C), developing country (D), andabackgroundregion(E). Peak1(BDE-3), 2(BDE-7), 3(BDE-15),
4
(BDE-17), 5 (BDE-28), 6 (BDE-47), 7 (BDE-49), 8 (BDE-71), 9 (BDE-66), 10 (BDE-77), 11 (BDE-85), 12 (BDE-99), 13 (BDE-100), 14 (BDE-119), 15
(
(
BDE-126), 16 (BDE-153), 17 (BDE-154), 18 (BDE-138), 19 (BDE-156), 20 (BDE-183), 21 (BDE-184), 22 (BDE-191), 23 (BDE-196), 24 (BDE-197), 25
BDE-206), 26 (BDE-207), and 27 (BDE-209).
Table 2. Recoveries, Relative Standard Deviations (RSD) of Recoveries, and
Limits of Detection (LODs) of 27 PBDE Congeners in Honey Samples
and developed countries. All the 27 congeners were quite
evenly present in honeys originating in developed countries while
the highly brominated PBDEs were more, and in higher con-
centrations, than less brominated congeners in honeys originating
in developing countries. Such results may be due to the long
history of PBDE uses in developed countries and decomposi-
tion of highly brominated congeners to less brominated ones
under natural conditions. Electronics industries are rapidly
changing in developing countries such as China and India and
the amount of PBDE products such as deca-BDE mixtures used
has been dramatically increasing. This may relate to the detection
of more highly brominated PBDEs in honeys from developing
BDE congeners (homologues) recoveries (%) RSD (%) LODs (pg/g ww)
BDE-3 (Br
BDE-7 (Br
1
)
)
75
80
10
15
15
20
20
20
10
10
18
18
13
14
11
15
18
13
15
10
19
10
9
0.6
0.6
1.50
2.3
2.0
1.5
0.8
0.7
0.6
0.8
3.8
1.2
0.81
1.6
4.0
9.2
8.6
5.5
5
2
BDE-15 (Br
BDE-17 (Br
BDE-28 (Br
BDE-47 (Br
BDE-49 (Br
BDE-71 (Br
BDE-66 (Br
BDE-77 (Br
BDE-85 (Br
BDE-99 (Br
2
)
)
)
)
)
)
)
)
)
)
85
3
3
4
4
4
4
4
5
5
93
110
105
101
120
98
89
countries.
P
98
The average concentrations of PBDE26 were 5950, 1870, and
113
85
640 pg/g ww in honey samples originating in developed countries,
BDE-100 (Br
BDE-119 (Br
BDE-126 (Br
BDE-153 (Br
BDE-154 (Br
BDE-138 (Br
BDE-156 (Br
BDE-183 (Br
BDE-184 (Br
BDE-191 (Br
BDE-196 (Br
BDE-197 (Br
BDE-206 (Br
BDE-207 (Br
5
)
)
)
)
)
)
)
)
)
)
)
)
)
)
developing countries and background regions, respectively. The
average concentrations of BDE-209 were 1170, 3390, and 450 pg/
g ww in honey samples originating in developed countries,
5
5
6
6
6
6
7
7
7
8
8
9
9
110
73
90
developing countries and background regions, respectively. The
120
106
96
P
concentrations of PBDE26 (excluding BDE-209) ranged from
2,720 to10,550 pg/g in the 21 honey samples originating in
P
96
9
developed countries. The concentrations of PBDE26 ranged
from 1,030 to 3,470 pg/g in the 15 honey samples originating
in developing countries and ranged from 300 to 850 pg/g in
the honey samples labeled as originating in background regions.
96
10
91
10
15
11
13
5
10
10
13
5
70
60
The concentrations of the four main congeners BDE-47, -49,
69
P
-
138, and -153 ( PBDE ) ranged from 630 to 7,520 pg/g, from
68
14
30
4
BDE-209 (Br10
)
82
9
230 to 1,920 pg/g, and from 100 to 600 pg/g in honey samples
originating in developed countries, developing countries, back-
ground regions, respectively. It is interesting that the average
concentrations of hepta- to deca-BDEs in honey samples origi-
nating in India, China and Thailand were approximately 3-5
times those in honeys originating in developed countries (data not
shown). The average level of the total 27 PBDEs in honey samples
from background regions was approximately 5 and 7 times lower
than that in honey samples from developing countries and
Figure 1 shows typical GC/ITMS chromatograms of PBDEs in
honey samples from different countries and regions. BDE-47, -49,
-138, and -153 are most commonly monitored congeners in
biological and environmental samples (26). They were found
to be major congeners in honey samples in the present study
P
(
Figures 1 and 2). Profiles of the 26 PBDEs ( PBDE )
26
except BDE-209 differed obviously in honeys from developing

3
498 J. Agric. Food Chem., Vol. 58, No. 6, 2010
Table 3. Average Concentrations of PBDEs in the Honey Samples from Different Countries
av concns ( std dev and concn ranges (pg/g ww)
developing countries (n = 15)
mean range
Wang et al.
developed countries (n = 21)
background regions (n = 14)
mean range
PBDE congeners
mean
range
a
BDE-3
BDE-7
260 ( 250
200 ( 205
95 ( 60
260 ( 210
220 ( 200
420 ( 560
210 ( 170
260 ( 170
50 ( 20
35-790
50 ( 40
6-120
20 ( 10
nd -40
nd-40
nd-150
nd-70
nd-60
10-410
nd-210
nd-30
nd-20
nd-30
nd-30
nd-20
nd-10
nd-10
nd-20
20-140
10-500
10-70
nd-20
10-120
nd-20
nd-80
nd-10
nd-80
nd-20
nd-70
nd-1170
100-600
300-850
20-580
20-210
20-580
10-560
20-1800
20-510
30-550
20-100
nd-70
10-590
10-500
10-170
nd-40
nd-330
20-1100
110-6170
10-690
nd-410
40-250
nd-1240
10-860
nd-650
10-280
nd-1740
nd-330
180-3360
630-7520
2720-10550
50 ( 30
50 ( 40
70 ( 50
60 ( 60
230 ( 250
80 ( 80
80 ( 70
35 ( 30
20 ( 30
40 ( 30
50 ( 50
20 ( 20
10 ( 10
20 ( 30
150 ( 140
360 ( 440
80 ( 60
5 ( 10
80 ( 120
50 ( 110
60 ( 90
50 ( 80
40 ( 70
40 ( 90
80 ( 100
3390 ( 2820
810 ( 4802
1870 ( 670
10-120
10-150
10-205
10-240
nd-910
nd-350
10-290
10-100
nd-140
nd-140
10-200
nd-60
10 ( 10
25 ( 40
30 ( 20
20 ( 20
110 ( 110
30 ( 50
10 ( 10
10 ( 10
10 ( 10
10 ( 10
10 ( 10
10 ( 10
10 ( 10
10 ( 10
80 ( 40
140 ( 120
20 ( 20
10 ( 10
30 ( 30
10 ( 10
20 ( 20
10 ( 10
20 ( 20
5 ( 5
BDE-15
BDE-17
BDE-28
BDE-47
BDE-49
BDE-66
BDE-71
BDE-77
BDE-85
BDE-99
BDE-100
BDE-119
BDE-126
BDE-138
BDE-153
BDE-154
BDE-156
BDE-183
BDE-184
BDE-191
BDE-196
BDE-197
BDE-206
BDE-207
BDE-209
30 ( 20
210 ( 200
180 ( 180
60 ( 50
20 ( 10
50 ( 90
460 ( 360
1520 ( 1730
260 ( 230
10 ( 10
100 ( 70
230 ( 350
290 ( 290
120 ( 180
110 ( 90
200 ( 490
120 ( 100
1170 ( 860
2620 ( 1870
5950 ( 2820
nd-30
nd-100
10-450
20-1700
10-260
nd-20
10-480
nd-510
nd-340
nd-320
nd-320
nd-410
nd-400
550-9260
230-1920
1030-3470
20 ( 20
450 ( 320
360 ( 140
640 ( 170
P
b
PBDE
PBDE26
4
P
c
a
b
c
Not detected. Sum concentrations of BDE-47, -49, -138 and -153. Sum concentrations of the 26 PBDEs except BDE-209.
developed countries, respectively (Table 3). The large data
dispersions may be attributed to different origins of the honey
samples, PBDE exposures in different regions, storage conditions
and time, honey processing and treatment variations, and un-
certainty of the actual origin of the honey samples. There was no
significant difference in concentrations of the total PBDEs and
congener profiles in the honey samples originating in developing
countries, developed countries and background regions. How-
ever, the average concentrations and congener profiles of PBDEs
indicate general trends of exposures to, and sources of, PBDEs in
honey.
report of BDE-209 degradation in honey was found in the
published literature. A preliminary study was conducted to
understand whether BDE-209 degrades in honey, which may be
a source of less brominated congeners in honey. Figure 3 shows
GC-ECD chromatograms of extracts of the BDE-209 fortified
honey samples after 4 weeks of incubation at 25 and 60 °C. The
chromatograms show degradation of BDE-209 in honey at 25
and 60 °C for 4 weeks. Four debromination products of BDE-209
are BDE-153, -183, -206 and -207, which were identified by
matching their mass spectra and GC retention times with those
of respective BDE congener standards. The peaks of BDE-206
and BDE-207 in Figure 3D are relatively smaller than the
corresponding peaks in Figure 3C while the peaks of BDE-153
and -183 in Figure 3D are relatively larger than the corresponding
peaks in Figure 3C. It is noteworthy that Figure 3A is a GC-ECD
chromatogram of an extract of a blank control honey sample
without any incubation and Figure 3B is a GC-ECD chromato-
gram of a recently purchased BDE-209 standard (unincubated
standard solutions). The three small peaks labeled as 2, 3, and 4
(unknown, BDE-207 and BDE-206, respectively) were impurities
in the standards. The abundance of these three impurities was less
than 3% based on the percentage of peak areas in Figure 3B. The
abundance of these three compounds was more than 25% based
on the percentage of peak areas in Figure 3C. Impurities in the
standard did not affect the analytical results.
The average concentration of BDE-209 in honeys labeled as
originating in developing countries was approximately 3-fold of
that in honeys originating in developed countries (Table 3). BDE-
209 was the dominant congener among all PBDE congeners
detected in honey samples. It averaged approximately 25% of the
P
PBDE26 in samples originating in developed countries and was
P
approximately 2-fold of the PBDE26 in samples originating
in developing countries (Table 3). The honey samples from the
background regions, i.e., Alaska, Hawaii and New Zealand,
contained very low concentrations of BDE-209 as well as the
other PBDEs. These findings indicate an agreement between
PBDE usages and their presence in honeys. Heavy uses of deca-
BDE mixtures are a primary suspected source of BDE-209 in the
honeys.
High concentrations of BDE-209 in various environmental
media raised concerns about whether BDE-209 in the environ-
ment was transformed into less brominated congeners. Studies
showed debromination of BDE-209 in the environment (1-3,27).
A number of recent studies have also shown that BDE-209 is
susceptible to breakdown under sunlight (28, 29). However, no
The results shown in Figure 3 suggest that BDE-209 may
undergo stepwise debromination to produce less brominated
congeners in honey. Debromination of BDE-209 in other ma-
trices also occurs under photochemical, hydrothermal and
reductive treatments (1, 2, 28-31). The results show that debro-
mination of BDE-209 is a source of less brominated congeners in

Article
J. Agric. Food Chem., Vol. 58, No. 6, 2010 3499
Figure 2. Average profiles of 27 PBDE congeners(pg/g ww) inthe honey samples labeled from the background regions, developing countriesand developed
countries.
honey. Degradation of BDE-209 in honey warrants further
investigation, particularly on degradation products and kinetics.
Information of BDE-209 degradation rates, products and path-
ways is important for understanding the sources of PBDEs in
honey. Such information is also significant for assessing human
exposures and risks associated with PBDEs (32, 33).
This may be attributed to the higher tendency of lower bromi-
nated congeners to vaporize relative to higher brominated
congeners and the potential decomposition of higher brominated
congeners to lower brominated ones. Honey samples from back-
ground regions displayed different PBDE compositional patterns
that had relatively lower abundance of higher brominated con-
geners than those in honey samples from developing countries.
The PBDEs in honeys from background regions may be partially
from long-range transport (34-37) rather than local sources.
Assuming all honey samples have been similarly aged and not
contaminated with additional PBDEs during transportation and
treatment processes, the fact that the concentrations of low
brominated congeners in honeys from developed countries were
higher than those from developing countries implies that the
lower levels of brominated congeners in honeys from developed
countries would primarily come from the environment.
Overall, the four main PBDE congeners, BDE-47, -49, -138
and -153, had an accumulative abundance of greater than 50% of
P
PBDE26 in all honey samples (Table 3), being similar to the
composition of the penta-BDE commercial formula (23). The
penta-BDE commercial mixture was a major brominated fire
retardant (BFR) product used in some developing countries (23),
in addition to the deca-BDE mixture (17). It is noteworthy that
the proportion of low molecular weight congeners detected in
honey samples from different countries was relatively greater than
that of high molecular weight congeners except for BDE-209.

3500 J. Agric. Food Chem., Vol. 58, No. 6, 2010
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Figure 3. GC-ECD chromatograms of an extractofa blank control honey
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and extracts of the BDE-209 fortified honey samples after 4 weeks of
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In summary, this study investigated the concentrations of 27
PBDEs in honey samples labeled as originating in 17 countries
and regions. The results from this data set showed higher levels of
P
the
PBDE , excluding BDE-209, in honey samples from
26
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153 were also dominant congeners and accounted for approxi-
P
mate 50% of the PBDE26 (excluding BDE-209). The findings
are consistent with long, heavy historical uses of PBDE products
in developed countries and current, heavy uses of BDE-209 in
developing countries. BDE-209 can be degraded to less bromi-
nated congeners in honey.
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Received for review September 7, 2009. Revised manuscript received
January 31, 2010. Accepted February 2, 2010. This project was
supported in part by the State of Hawaii Department of Agriculture,
the Hawaii Farm Bureau Federation, the Hawai‘i Beekeepers’
Association, CTS Foundation, and the National Honey Board.