ARTICLE
pubs.acs.org/est
Halogenated POPs and PAHs in Blood Plasma of Hong Kong Residents
)
Yan Yan Qin,† Clement K. M. Leung,‡ C. K. Lin,§ Anna O. W. Leung,† Hong Sheng Wang,†
John P. Giesy, ,^,#,r,O and Ming H. Wong†,*
†
Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Hong Kong, PR China
IVF Centre Limited, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, PR China
§
Hong Kong Red Cross Blood Transfusion Service, 15 King's Park Rise, Kowloon, Hong Kong, PR China
Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
^
Department of Zoology, and Center for Integrative Toxicology, Michigan State University, East Lansing, MI, USA
#
Department of Biology & Chemistry, City University of Hong Kong, Kowloon, Hong Kong, SAR, China
r
School of Biological Sciences, University of Hong Kong, Hong Kong, SAR, China
O
Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
)
‡
bS Supporting Information
ABSTRACT: The objective of this study was to quantify organic chlorinated pesticides (OCPs), polychlorinated biphenyls (PCBs),
polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in blood plasma collected from 111
healthy residents in Hong Kong to assess the levels of these pollutants in the general population during the period of March to April,
2008. Concentrations of these residues in blood plasma obtained from the Hong Kong Red Cross Blood Transfusion Service were
determined by gas chromatography-mass spectrometry. Naphthalene, phenanthrene, p,p0 -DDE, PCB-180, and PBDE-47 were
detected in 100% of the participants. Females had significantly greater concentrations of acenaphthylene (female: 93.3 ng/g lipid;
male: 39.8, p < 0.05), anthracene (22.3; 15.3, p < 0.05), fluoranthene (138; 125, p < 0.05), p,p0 -DDE, p,p0 -DDT, PCB-183, BDE-99
than males. Blood of smokers contained significantly greater (p < 0.05) concentrations of acenaphthene, benzo(a)pyrene, p,p0 -DDE,
p,p0 -DDT, PCB-138, BDE-47, and BDE-99 than did blood of nonsmokers. Positive correlations were found between concentrations
of each class of pollutant, with respect to seafood diet habit, Body Mass Index (BMI), and age. Concentrations of HCHs and DDTs
in blood plasma of healthy Hong Kong residents were greater than those of other countries, and it was found that smoking,
consumption of a seafood diet, BMI, and age could influence concentrations in human blood.
’ INTRODUCTION
Due to rapid industrial development in China, there is an
urgent need to study the relationship between environmental
pollution and human health.1 POPs such as OCPs, PCBs,
PBDEs, in addition to PAHs have become major human health
concerns. Their ubiquitous environmental occurrence, biochemical and toxic effects, linking to human exposure and health risk
have been investigated.2,3 The results of a previous study revealed
that significantly greater (p < 0.05) concentrations of DDTs,
HCHs, PCBs, PAHs, and PBDEs were detected in the subcutaneous fat of patients with uterine leiomyomas (UL) when
compared with those of the control group and that OCPs, PCBs,
PAHs, and PBDEs may be correlated with UL for Hong Kong
residents.4 It has also been suggested that DDTs and HCHs may
increase a woman's risk of breast cancer in China.5 Moreover,
exposure to DDTs and HCHs was associated with adverse
developmental outcomes, including fetal death, intrauterine
growth restriction, preterm birth, and birth defects.6
There has been wide historical use of OCPs, PCBs, and
PBDEs. For example, OCPs such as DDTs and HCHs were
produced and used extensively to increase agricultural
production 7 while PCBs were often used in transformers,
r 2011 American Chemical Society
hydraulic fluids, printing, and other applications8 and PBDEs
continue to be used as additive flame-retardants in plastic
materials, paints, and textile fabrics in certain regions of the
world resulting in wide occurrence in the environment, leading to
elevated concentrations in human milk.9,10 Although DDTs and
HCBs were banned in 1983 for agricultural application in China,
their residues are still found in some areas, including the Pearl
River Delta.1,11 PCBs were banned in a number of countries since
the 1970s8 and also in China (since early 1980s).12 PAHs are
mainly produced from incomplete combustion of different fuels
such as oil, petroleum gas, coal, and wood and also through
cigarette smoke and barbecue.13 PAHs are ranked in the top 8 of
the 2007 list of the most hazardous substances in the environment, prepared by the Agency for Toxic Substances and Disease
Registry,14 with benzo[a]pyrene (BaP) topping the list. Our
previous studies have also indicated that common marine and
freshwater fish collected from various freshwater fish ponds and
Received: July 19, 2010
Accepted: December 12, 2010
Revised:
December 6, 2010
Published: January 5, 2011
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mariculture sites around the Pearl River Delta (including Hong
Kong) were grossly polluted by DDTs, PCBs,15,16 and greater
concentrations of these contaminants detected in human milk
were significantly correlated with consumption of fish by the
mothers.17,18 Most of these pollutants are toxic, persistent,
bioaccumulative, and lipophilic. If they enter into food chains,
they are biomagnified, with all the halogenated POPs stored in
the lipid for a long time resulting in great concentrations in the
human body.19
Although a number of studies reported the contaminations of
POPs in different environmental compartments,1,12,15 human
body burdens of these pollutants can better reflect their toxicities
on human health.20,21 There have been a number of studies
which have investigated chemical concentrations of POPs in
human populations using human adipose tissues,17,22 milk, 18,23
and blood.24,25 Adipose tissues could be obtained during surgery,
but this matrix is not readily available. A limitation to the use of
human milk is that it can only be obtained from the female
population and only during lactation in the reproductive age.
Blood samples, however, are more readily available and recruitment is easier, and blood can be obtained from both genders of a
wide age range.
Several previous studies have used PCBs and DDTs in human
blood as exposure biomarkers for evaluating exposure sources
and potential adverse health effects;5,6,26 however, the concentrations of POPs in blood plasma of humans in Hong Kong have
not been reported. Since blood samples can cover a wide range of
age and both genders, it was used as a medium to assess the levels
of these pollutants in the general population of Hong Kong and
their health effects.27 Therefore, the objectives of this study were
to determine the concentrations of PCBs, OCPs, PBDEs, and
PAHs in blood plasma from 111 people in Hong Kong through
the Hong Kong Red Cross and to study the association of
concentrations of POPs with age, Body Mass Index (BMI),
seafood diet habit, and smoking habit.
’ EXPERIMENTAL SECTION
Sampling and Preparation. A total of 111 participants
(blood donors) were recruited during March to April, 2008
and grouped under different age groups 20-30, 31-40, 41-50,
and 51-60 years old. All participants were eligible as blood
donors based on their health history status and screening by a
nurse at the Red Cross before recruitment into the study.
Informed consent was then obtained from each participant,
together with a short questionnaire (given by staff of Hong
Kong Baptist University, self-reported by participant) recording
details on age, weight, height, and number of seafood meals per
week for the association study.
Analyses of POPs. The methods were based on previous
studies with some modifications.28,29 Before extraction, the
surrogates m-terphenyl, 13C-β-HCH, 13C-p,p0 -DDT, 13C labeled
PCB 28, 52, 101, 138, 153, 180, 209, unlabeled BDE 77, 116, and
126 (50 ng) were spiked separately into the blood plasma
samples and kept at 4 C overnight for equilibrium before sample
extraction. The solid phase extraction (SPE) column was washed
with DCM and activated with methanol and Milli-Q water. After
conditioning, the SPE column was not allowed to dry, and 2 mL
plasma was added into column. The column was then dried for
15 min by aspiration of ambient air. Subsequently, 50 mL of
DCM:n-hexane (1:1, v/v) was added to the column for elution.
The extract was further cleaned up by Florisil column (modified
ARTICLE
from USEPA 3620C)30 and concentrated to 0.5 mL before
analysis by Gas Chromatography-Mass Spectrometer (GCMS). Concentrations of PAHs, OCPs, PCBs, and low molecular
weight PBDEs were determined with a Hewlett-Packard (HP)
6890 N gas chromatograph (GC) coupled with a HP-5973 mass
selective detector (MSD) and a 30 m 0.25 mm 0.25 μm DB5 capillary column (J & W Scientific Co. Ltd., USA). BDE-209
was analyzed with a 15 m DB-5HT capillary column (0.25 mm i.
d., 0.1 μm film thickness). Internal standards acenaphthene-d10,
phenanthrene-d10, chrysene-d12, perylene-d12 for analysis of
PAHs, OCPs, deuterated PAHs (phenanthrene-d10, chrysened12 and perylene-d12), and PCB 209 for analysis of PCBs, 13Clabeled PBDE 3, 15, 28, 47, 99, and 153 for analysis of PBDEs
were added respectively. Total lipids in plasma were determined
gravimetrically31 (details in the Supporting Information).
Quality Assurance/Quality Control. For every sequence of
10 samples, a solvent blank and a procedural blank were added to
ensure that the samples and the analysis process were free of
contamination. Four quality control criteria were used to ensure
the identification of POPs congeners in the plasma samples:
First, retention times matched with those of the authentic
reference compounds. Second, the ratios of the two characteristic
ions were within 15% of the theoretical values. Third, the signalto-noise (S/N) ratio was greater than three for the selected ions.
Fourth, the amount of the analytes in the sample had to be at least
two times that in the blank sample if there were interferences. If
any of these four criteria failed, the congener was excluded. The
average procedural blank value was subtracted from each sample
when appropriate. The limit of detection (LOD) (in ng/g lipid)
of PAHs, OCPs, PCBs, and PBDEs defined as standard deviation
from mean blank (n = 3) was 1-5, 2, 0.6, 0.2, respectively. The
recoveries of spiked plasma samples for PAHs ranged from 79 to
98%, PCBs from 75 to 92%, HCHs and DDTs from 82% to
103%, and PBDEs from 79 to 107%. If a congener was below the
LOD, its concentration was assumed to be LOD/2. Reported
concentrations were not corrected with recovery rates. Six-point
calibration curves were constructed for the quantification, with
good to excellent linearity (r2 > 0.99).
Statistical Analyses. Data were presented as median, mean
( SD, and analyzed using SPSS 16.0 software. Inspection of a
normal probability plot (Q-Q plot) and the Shaprio-Wilk statistic
were used to test the normality of primary data. The data were
log-transformed prior to conducting statistical tests. The effects
of age and cofactors sex and seafood diet on pollutants body
burden were determined by two-way ANOVA model. Student t
test was used to compare the concentrations of pollutants
between female and male, smokers and nonsmokers. Duncan's
Multiple Range Test was performed for investigating the bivariate relationships between seafood diet habit, BMI, age, and
concentrations of pollutants after one-way ANOVA test. Correlation analysis between concentrations of pollutants and amount
of seafood consumed, BMI, and age was conducted using
Pearson's correlation method.
’ RESULTS AND DISCUSSION
POPs Concentrations. PAHs, OCPs, PCBs, and PBDEs
concentrations were detected in human blood plasma
(Figure 1 and Table 1). While exposure to PAHs is usually
monitored through the measurement of hydroxylated metabolites in urine,32 parent compounds of PAHs can also be
detected in blood plasma. Among individual PAHs, naphthalene
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ARTICLE
Figure 1. Box plots of total PAHs, DDTs, HCHs, PCBs, and PBDEs concentrations in female and male blood plasma. Total HCHs refer to the sum of βHCHþ γ-HCH, Total DDTs refer to the sum of pp-DDE and pp-DDT, and Total PAHs, PCBs, and PBDEs represent the sum of all the compounds.
(female: 305 ng/g lipid; male: 310) and phenanthrene (430;
316) were the dominant congeners detected in both females and
males, followed by pyrene (193; 215), fluorene (160; 130).
Individual PAH compounds such as naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, and chrysene were detected
in more than 90%, while benzo(bþk)fluoranthene and benzo(a)pyrene in about 60% of the samples from both female and
male participants. These compounds are the main byproduct of
pyrolytic processes, such as incomplete combustion of organic
materials during the processing of coal and crude oil, combustion
of natural gas, including vehicle traffic, cooking, and tobacco
smoking.33 Females showed significantly greater concentrations
of acenaphthylene (female: 93.3; male: 39.8, p < 0.05), anthracene (22.3; 15.3, p < 0.05), and fluoranthene (138; 125, p < 0.05)
than males, while males accumulated significantly greater pyrene
(193; 215, p < 0.05) than females.
HCHs and p,p0 -DDE were detected in the blood plasma of
100% of the samples, while p,p0 -DDT and HCB in about 90%
and 80%, respectively. p,p0 -DDE was the most abundant congener of the DDTs detected in both females and males. Previous
studies also revealed that DDE is the most commonly detected
congener of DDTs in the general population (UK;25 Southern
Spain34). Samples of blood from females contained significantly
greater concentrations of p,p0 -DDE (female: 1219; 961, p < 0.05)
and p,p0 -DDT (63.7; 60.3, p < 0.05) than did that of males.
PCB congeners 118, 180, 153, and 138 were detected in more
than 90% of the blood samples, with PCB-180 being the
predominant congener in both females (49.5 ng/g lipid) and
males (43.8). It has been reported that PCB-153, -180, and -138
were the dominant congeners (Thomas et al.25 and Petrik et
al.35). Blood of female participants contained greater PCB-183
(2.31; 2.05, p < 0.05) concentrations than did those of males.
PBDE-47 and -153 were detected in 100% of the blood samples,
with BDE-47 being the most dominant congener. BDE-209, the
predominant congener in the deca-BDE commercial product,25 was
found in half of the blood samples. This result is consistent with the
results of other studies in the US and Norway.36 This may be due to
the fact that less brominated BDEs have longer half-lives (years) and
could be formed through debromination of more brominated
congeners.37 The finding that females accumulated higher concentrations of PAHs, DDTs, PCBs, and PBDEs than males was in line
with a previous study26 and may have resulted from differences in
dietary exposure or metabolism.38
Comparison among Concentrations of POPs in Blood of
Humans in Different Countries. Concentrations of OCPs in
human blood from different countries were compared (Table S1
Supporting Information). Concentrations of p,p0 -DDE in blood
of people from Mexico (2770 ng/g lipid)39 were greatest, while
the least concentrations were observed in blood of people living
in Japan (93.0).24 The concentration of p,p0 -DDE (1057)
observed in the present study was similar to that detected in
Thailand (1191).40 The greatest concentration of p,p0 -DDT was
observed in Bangladesh (1340),41 while the least were found in
Japan (2.40).24The ratio of p,p0 -DDE/p,p0 -DDT is an indicator
of whether the DDT observed was recently released from
technical material or had been weathered in the environment.
In general, a lesser p,p0 -DDE to p,p0 -DDT ratio is an indication of
more recent exposure to DDT; conversely, a greater ratio
indicates that the DDT complex had been more weathered.42
The greatest ratio of p,p0 -DDE/p,p0 -DDT was observed in
Slovakia (41.5),35 while Bangladesh (1.19)41 had the least ratio.
This indicated a more recent exposure to DDT. The ratio
observed in the present study (16.8) was least among these
countries, which is consistent with the conclusion that people in
Hong Kong are exposed to more recently applied DDT.
Alternatively, blood samples from Hong Kong (206 ng/g
lipid) contained the greatest concentration of HCHs, with the
least concentration in Poland (2.00).23 China is the largest
producer and user of technical HCHs in the world, with the
total production of HCH estimated to be 4.9 million tonnes,
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Table 1. Concentrations of PAHs, DDTs, PCBs, and PBDEs (ng/g lipid) in Human Blood Plasma Collected from Hong Kong
femalea (n = 51)
compound
*
malea (n = 60)
mean ( SD
median
range (min-max)
%>LOD
mean ( SD
median
range (min-max)
%>LOD
100
naphthalene
316 ( 131
305
86.0-617
100
343 ( 106
310
110-590
acenaphthylene
78.0 ( 59.1*
93.3
15.3-228
100
38.8 ( 11.0
39.8
9.75-172
100
acenaphthene
54.6 ( 26.4
67.3
7.25-264
100
54.4 ( 32.5
50.3
10.3-152
100
fluorene
124 ( 60.6
160
47.0-287
100
105 ( 38.7
130
30.5-203
100
phenanthrene
366 ( 233
430
131-797
100
303 ( 126
316
116-674
100
anthracene
10.8 ( 9.81*
22.3
2.25-54.0
100
6.82 ( 2.35
15.3
1.25-31.0
100
fluoranthene
106 ( 46.2*
138
38.5-272
100
88.5 ( 39.5
125
25.0-206
100
pyrene
benz(a)anthacene
184 ( 47.5*
27.7 ( 16.7
193
45.8
99.0-305
5.75-137
100
100
212 ( 52.7
25.9 ( 7.08
215
30.1
75.8-312
2.50-80.5
100
96
chrysene
12.6 ( 5.65
13.5
1.50-40.3
87
11.9 ( 5.04
12.9
1.50-51.8
92
benzo(bþk)fluoranthene
14.7 ( 8.02
9.32
0.60-38.4
70
16.5 ( 8.21
14.8
0.60-40.4
68
benzo(a)pyrene
7.63 ( 1.06
5.25
0.50-10.6
72
7.05 ( 3.03
6.01
0.50-15.2
62
HCB
16.7 ( 13.8
20.3
1.50-49.5
89
12.8 ( 5.45
21.8
1.50-47.5
82
pp-DDE
942 ( 224*
1219
420-2540
100
756 ( 312
961
306-2193
100
pp-DDT
71.9 ( 43.9*
63.7
2.25-177
95
55.2 ( 46.7
60.3
2.25-209
97
PCB74
PCB123
1.90 ( 0.21
2.89 ( 0.67
1.63
1.50
0.30-2.85
0.31-3.42
91
56
1.75 ( 0.17
2.88 ( 0.24
1.61
1.85
0.30-2.20
0.31-3.22
42
51
PCB118
15.3 ( 6.56
22.2
12.2-59.7
100
14.3 ( 4.34
20.2
10.1-41.5
100
PCB126
0.67 ( 0.28
0.30
0.30-1.43
79
0.54 ( 0.18
0.30
0.30-0.81
77
PCB180
51.7 ( 10.1
49.5
11.5-85.5
100
48.5 ( 11.8
43.8
10.5-87.5
100
PCB138
15.9 ( 6.40
21.6
1.75-55.1
100
14.9 ( 5.10
21.7
2.78-49.0
100
PCB153
10.9 ( 7.33
11.5
0.35-31.7
96
9.77 ( 4.93
10.3
0.35-28.4
91
PCB156
0.74 ( 0.19
0.32
0.32-1.38
92
0.69 ( 0.50
0.32
0.32-4.20
90
PCB183
PCB169
2.38 ( 0.97*
0.47 ( 0.19
2.31
0.30
0.31-6.80
0.30-1.17
82
79
2.09 ( 0.90
0.48 ( 0.17
2.05
0.30
0.31-4.95
0.30-1.30
75
84
BDE47
2.57 ( 0.35
2.97
2.08-5.57
100
2.59 ( 0.64
2.83
2.07-6.42
100
BDE100
0.06 ( 0.02
0.10
0.10-0.21
63
0.06 ( 0.03
0.10
0.10-0.26
59
58
BDE119
0.05 ( 0.04
0.12
0.12-0.42
53
0.05 ( 0.03
0.12
0.12-0.40
BDE99
0.11 ( 0.06*
0.15
0.15-0.72
55
0.06 ( 0.04
0.15
0.15-0.30
56
BDE85
0.17 ( 0.06
0.27
0.13-0.74
71
0.12 ( 0.03
0.21
0.13-0.62
75
BDE154
0.06 ( 0.03
0.10
0.10-0.38
50
0.05 ( 0.02
0.10
0.10-0.37
57
BDE153
BDE184
0.67 ( 0.20
0.43 ( 0.15
0.75
0.49
0.46-1.25
0.21-1.01
100
56
0.63 ( 0.24
0.39 ( 0.11
0.79
0.41
0.45-1.47
0.21-1.39
100
61
BDE183
0.30 ( 0.16
0.38
0.14-0.81
69
0.27 ( 0.24
0.32
0.14-0.88
74
BDE209
1.32 ( 0.86
1.44
1.05-3.86
60
1.03 ( 0.83
1.73
1.05-3.66
52
p < 0.05, between female and male (Student t-test). a Represent information in female and male: female number is 51, BMI is 22.6 ( 3.62, age is 37.2 (
12.2, smoking number is 6; male number is 60, BMI is 23.2 ( 3.14, age is 39.7 ( 11.7, smoking number is 9; total participant number is 111, BMI is
23.0 ( 3.61, age is 38.5 ( 11.9, smoking number is 15.
which accounts for 33% of the total world production.43,44 The
Pearl River Delta in southern China is one of the most developed
and prosperous regions in the country and also has a history of
having the greatest rates of pesticide application in the country.
The average annual application from 1980 to 1995 in the region
was four times greater than the country's average annual application and reached 37.2 kg/ha.45
Concentrations of PCBs in human blood were compared
among countries (Table S2 in the Supporting Information).
The concentrations of PCBs in human blood from Hong Kong
(110 ng/g lipid) was similar to Bangladesh (91.7)41 but less than
that observed in the Europe countries. In the present study
concentrations of PCB congeners 153, 180, 138 were 11.0, 45.6,
and 21.6, respectively, which were less than those observed in
Sweden (296, 207, 134)46 and Spain (183, 120, 105).47 This
result might be due to the relatively fewer industrial activities in
Hong Kong (1970s), compared with urban areas of other
developed regions (1950s and 1960s).17 Since the worldwide
ban of PCBs around late 1970s-early 1980s,8,12 small concentrations of PCBs were detected in different food items including
fish, meat, and vegetables collected from Shanghai, China.44 The
present study also provides additional information showing that
concentrations of PCBs in human blood plasma in Hong Kong
were generally low.
Concentrations of PBDE in human blood from studies among
different countries were compared (Table S3 in the Supporting
Information). The total PBDE concentration obtained in this
study was similar to those observed in other countries, but less
than those in Korea and the USA. In Japan, the PBDEs
concentration found in 1980 (1.20 ng/g lipid)48 compared with
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Figure 2. Concentrations of PAHs, DDTs, PCBs, and PBDEs (ng/g lipid) in human blood plasma between smokers and nonsmokers: * p < 0.05, ** p <
0.01 between smoker and nonsmoker (Student t test).
that in 1995 (8.50)48 indicated that PBDE contamination had
increased with time. Concentrations of PBDE in blood of Hong
Kong residents (5.56) were approximately 10-fold less than the
mean concentration observed in blood plasma of people from the
USA (61.0).49 The concentration of BDE 47 (2.90) was also ten
times less than in the USA (34.0).49 The concentration of BDE
209 measured in this study (1.59) was less than that found in the
UK (83.0).25 This is likely due to the fact that the USA has strict
fire resistance laws for furniture, and PBDEs are used as flameretardant additives in plastics, foams, electrical appliances, television sets, computer circuit boards, and casings.10 The global
demand for PBDEs reached 200,000 tonnes in 2003, with half of
the PBDEs and 95% of the PentaBDE used worldwide being
consumed in North America.50 This then leads to greater
exposure of the general population of the USA to PBDEs than
people living in other countries.
Contributing Factors to POPs Concentrations in Human
Blood Plasma. Concentrations of PAHs, OCPs, PCBs, and
PBDEs in human blood plasma collected from Hong Kong
residents were correlated with seafood diet. POPs concentrations
in seafood (including fish, shrimp, shellfish, and mussel) were
measured in samples collected from Hong Kong markets. There
were statistically significant correlations between the amount of
seafood in the diet and concentrations of fluorene (r = 0.557, p <
0.05), p,p0 -DDE (r = 0.527, p < 0.05), p,p0 -DDT (r = 0.502, p <
0.05), DDTs (r = 0.533, p < 0.05) and PCB-126 (r = 0.579, p <
0.05) in human blood plasma (adjusting for age in a two-way
ANOVA, seafood diet*age >0.05, Table S4 in the Supporting
Information). Diet has long been believed to be the predominant
source of human exposure to POPs through bioaccumulation in
food chains. The average Hong Kong person consumes fish or
shellfish four or more times per week, with an average mass of
164.4 g consumed per day.51 A previous study showed that DDT
levels in fish species such as snubnose pompano (133 ng/g wet wt)
and golden threadfin bream (59.8 ng/g wet wt) investigated in
Hong Kong were higher than the guideline of 14.4 ng/g wet wt
for human consumption.15 Moreover, previous studies also
observed that concentrations of DDTs and PCBs in human milk
and adipose tissue collected from Hong Kong were significantly correlated with frequency of fish consumption of the
donors.4,18
POPs are ubiquitous environmental pollutants. They can
also be found in indoor environments and inhalation is
another important exposure pathway.52 Concentrations of
PAHs, OCPs, PCBs, and PBDEs in blood plasma were
compared between smokers and nonsmokers in Hong Kong
(Figure 2). Due to the limited number of smokers in this
study, student t test was used to make a comparison between
smokers and nonsmokers. Compounds such as acenaphthene
(smoker: 84.0 ng/g lipid; nonsmoker: 49.9, p < 0.05), benzo(a)pyrene (15.0; 7.27, p < 0.05), p,p0 -DDE (908; 831, p <
0.05), p,p0 -DDT (65.6; 62.0, p < 0.05), DDTs (973; 893, p <
0.05), PCB-138 (19.5; 14.7, p < 0.05), PBDE-47 (2.94; 2.52,
p < 0.01), and PBDE-99 (0.09; 0.03, p < 0.05) were significantly greater in smokers than in blood of nonsmokers.
Tobacco smoke is a major source of human exposure to PAHs.
A previous study showed that the concentrations of PAHs,
especially BaP (two times greater), were greater in lung tissues
of smokers than those of nonsmokers.53 The concentrations of BaP observed in this study confirmed this finding
(smoker:15.0 ng/g lipid; nonsmoker: 7.27). The present
study also showed that there were greater concentrations
(p < 0.05) of p,p0 -DDE, p,p0 -DDT, and DDTs in blood plasma
of smokers. This is consistent with the findings that organochlorine concentrations in human plasma were positively
correlated with smoking.54 It has been reported that smoking
during pregnancy was associated with greater concentrations
of both PCBs and PBDEs in cord blood.55 In recent years, it
has been observed that house dust is an important source
of PBDEs,56 and ingestion absorption is estimated to be a
significant parameter in human exposure to PBDEs.52 The
greater PCBs and PBDEs concentrations in smokers may be
due to the smokers' hand-to-mouth behavior which can
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Environmental Science & Technology
increase oral ingestion of contaminated dust in the environment.55 Although not readily explained, these associations
between smoking and PCBs and PBDEs were consistent
warranting further studies.
Concentrations of PAHs, OCPs, PCBs, and PBDEs in human
blood plasma were found to be correlated with BMI (see
Table S5, Supporting Information). Concentrations of chrysene
(r = 0.505, p < 0.05), p,p0 -DDE (r = 0.649, p < 0.05), DDTs
(r = 0.613, p < 0.05), PCB-138 (r = 0.582, p < 0.05), and PCBs
(r = 0.560, p < 0.05) were significantly correlated with BMI.
Significant correlations between BMI and PCBs and DDTs in
blood were also observed by Hanrahan et al.57 These results
indicated that BMI is an important factor influencing the body
burdens of these pollutants, possibly due to the bioaccumulative
and lipophilic nature of these pollutants.19
Table S6 (see Supporting Information) shows the mean concentrations of PAHs, OCPs, PCBs, and PBDEs in human blood plasma
of different age groups. p,p0 -DDE (female: r = 0.607, male: r = 0.729,
p < 0.05), DDTs (female: r = 0.591, male: r = 0.678, p < 0.05), PCB180 (male: r = 0.507, p < 0.05), PCBs (female: r = 0.519, male: r =
0.502, p < 0.05), BDE-209 (female: r = 0.583, male: r = 0.516, p <
0.05), and PBDEs (female: r = 0.532, male: r = 0.545, p < 0.05) were
significantly correlated with age. Previous studies have reported
significant correlations between pesticide levels in blood and
age.54,58 A study which analyzed blood samples of thirteen family
members from twelve EU countries in order to identify persistent and
bioaccumulative chemicals showed that p,p0 -DDE was detectable in
blood samples of three generations, and the greatest found in
grandmothers who had concentrations that were 2-fold greater than
mothers, with the least found in their children (three times less than
their mothers).58 No significant correlations between donor age and
concentration of PBDEs were obtained in Belgium and New
Zealand,22,59 but the present study indicated that the 51-60 age
group contained the greatest concentrations of PBDEs. It was found
that women between 20 and 40 years of age had a significantly (p <
0.05) lesser average concentration of DDTs than in women in the age
groups of 41-50 and 51-60, which indicates that breast-feeding
provides a possible mechanism for the elimination of organochlorine
pesticides.60
The greater concentrations of HCHs and DDTs detected in
human blood plasma of the present study compared with other
countries was linked to the great concentrations of DDTs detected in
fish in Hong Kong markets15 because there was a significant
correlation (p < 0.05) between the frequency of seafood consumption
with the accumulation of DDTs and HCH in human milk and
adipose of people in Hong Kong.4,18 Furthermore, relatively great
concentrations of DDTs and HCHs in adipose tissue of patients in
Hong Kong with UL4 indicated that DDTs and HCHs are great risk
factors that affect human health via frequent fish intake.
There are several limitations to the present study in that blood
samples were only obtained from one blood donor center; therefore,
most of the donors may live or work near the center, and the study
group was not a random sample of the population. There may also be
characteristics of self-selected individuals that make them different
from the general population, such as health, or some types of
behaviors; however, it is difficult to determine what these factors
might be. There was no indication from our data that the volunteers of
this study were significantly different from the general population.
The volunteers examined in this study represented a broad age
group, both genders, and a range of lifestyle and personal factors
that may influence chemical exposure and concentrations in
individuals. Our result serves as an early warning that a diet of
ARTICLE
contaminated fish, smoking, and continued environmental pollution in air and water in the Pearl River Delta will lead to the
accumulation of PAHs, OCPs, PCBs, and PBDEs in the body,
which is potentially harmful to health. Donor blood from the Red
Cross could serve as a good benchmark matrix for future regional
or global pollution surveillance studies.
’ ASSOCIATED CONTENT
bS
Supporting Information. Tables S1, S2, S3, S4, S5, and
S6. This material is available free of charge via the Internet at
http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Author
*Phone: 852-34117746; fax: 852-34117743; e-mail: mhwong@
hkbu.edu.hk.
’ ACKNOWLEDGMENT
Financial support from Research Grants Council of Hong Kong
(HKBU 2482/05 M, RC/AOE/08-09/01, and SEG HKBU09) is
gratefully acknowledged. The authors would like to thank the
participants for donating blood samples, and the doctors and nurses
involved for technical assistance. Prof. Giesy was supported by the
Canada Research Chair program and an at large Chair Professorship
at the Department of Biology and Chemistry and State Key
Laboratory in Marine Pollution, City University of Hong Kong.
’ NOMENCLATURE
BMI
body mass index
GC-MS gas chromatography - mass spectrometer
OCPs organic chlorinated pesticides
PAHs polycyclic aromatic hydrocarbons
PBDEs polybrominated diphenyl ethers
PCBs polychlorinated biphenyls
POPs persistent organic pollutants
DDTs dichlorodiphenyltrichloroethane
HCBs hexachlorobenzene
HCHs hexachlorocyclohexane
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