Environmental Toxicology and Chemistry, Vol. 29, No. 10, pp. 2135–2142, 2010
# 2010 SETAC
Printed in the USA
DOI: 10.1002/etc.315
Critical Review
DIETARY INTAKE OF PERSISTENT ORGANIC POLLUTANTS AND POTENTIAL HEALTH
RISKS VIA CONSUMPTION OF GLOBAL AQUATIC PRODUCTS
HUAN-YUN YU,yz YING GUO,yz and EDDY Y. ZENG*y
yState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
zGraduate School, Chinese Academy of Sciences, Beijing 100049, China
(Submitted 4 March 2010; Returned for Revision 21 May 2010; Accepted 23 June 2010)
Abstract— The concentration levels of typical persistent organic pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofur-
ans (PCDD/Fs), polychlorinated biphenyls (PCBs) including dioxin-like PCBs (DL-PCBs) and non–dioxin-like PCBs, organochlorine
pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) in global aquatic products from major producing countries were
summarized. Daily intakes of these compounds via consumption of various aquatic products for global consumers were also estimated
based on available literature data. Risk assessment based upon existing criteria for OCPs and PBDEs shows that there is minimal risk to
global consumers from consumption of aquatic products, with the exception of products from specific regions located around known
heavy-point sources. Exposure to dioxins through consumption of aquatic products, excluding marine fish, is also in the range of the
acceptable level, lower than 4 pg World Health Organization toxic equivalent (WHO-TEQ)/kg bw/d; however, dioxin intake via marine
fish may cause hazards to human health, especially for Europeans. Regarding PCBs, there is cancer risk for global consumers via
consumption of aquatic products, especially marine fish, based on cancer and noncancer hazard ratio assessment. Generally, European
consumers have higher exposure levels of PCDD/Fs and DL-PCBs, while Americans and Asians have relatively higher exposure levels
of OCPs and PCBs. In contrast, all global populations are found to have lower exposure levels of PBDEs, which may be attributed to its
relatively shorter history of use compared with PCBs and OCPs. Finally, the estimated total amounts of PCBs, OCPs, and PBDEs stored
in global aquatic products constitute only a small portion of the total amount that has been used, and the majority obviously occurs in
other environmental media or even remains in commercial products. Environ. Toxicol. Chem. 2010;29:2135–2142. # 2010 SETAC
Keywords—Persistent organic pollutants
Aquatic products
Dietary intake
Global consumers
Risk assessment
shellfish provide high-quality protein and other essential
nutrients, are low in saturated fat, and are a highly recommended dietary source for omega-3 fatty acids. Because of this
high nutritional value, fish and shellfish have thus become an
important part of a healthy diet worldwide [18]. Given the
dietary importance and widespread popularity of aquatic products, we have attempted here to conduct preliminary estimates
of daily dietary intakes of the four typical pollutant groups
through consumption of aquatic products. In addition, to assess
human health risk from the four pollutant groups, we compare
these estimated daily intake rates for aquatic consumption with
various applicable standards, limits, or similar health advisories
set by different organizations or countries worldwide. It should
be noted that the range of aquatic products targeted in the
current review includes marine and freshwater fish and shellfish, and species will be specified wherever appropriate
throughout the review.
INTRODUCTION
Persistent organic pollutants (POPs) important to human
health include polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) including
both dioxin-like PCBs (DL-PCBs) and non–dioxin-like
PCBs, organochlorine pesticides (OCPs), and polybrominated
diphenyl ethers (PBDEs). A previous review comprehensively
considered the persistence, long-range atmospheric transport,
bioaccumulation in biota, food-web biomagnifications, and
adverse effects upon human and ecosystem health as the main
reasons why PCDD/Fs, PCBs, and OCPs attracted considerable
attention worldwide [1]. The four major endpoints of toxicological concern for these compounds include endocrine disruption in humans and wildlife [2–5], reproductive and
developmental toxicity [6], central nervous system effects
[7,8], and damage to the immune system of top-predator species
[9]. These chemicals are typically hydrophobic and lipophilic,
so they are readily sequestered in adipose tissue and are
bioaccumulated/biomagnified into higher trophic levels in the
food web. It is well accepted that dietary intake is the major
route for human exposure to these chemicals, compared to other
routes such as inhalation and dermal contact [10–13].
Numerous researchers have shown that human dietary exposure to POPs is largely attributable to consumption of aquatic
products [13–17]. It is likewise well established that eating
aquatic products also offers many nutritional benefits. Fish and
METHODS
Data collection
Data related to the concentrations of these four typical
pollutant groups in aquatic products from major aquaculture
countries were collected from the following world regions:
Africa—Egypt and Tanzania; North and South America—
Brazil, Canada, Chile, and the United States; Asia—China,
India, Indonesia, Japan, South Korea, and Vietnam; Europe—
Belgium, Denmark, Norway, Spain, Sweden, and Switzerland;
and Oceania—Australia (Sydney). Wherever possible, data
were obtained preferentially from the most recent available
literature (published after 2000). Information and statistics
All Supplemental Data may be found in the online version of this article.
* To whom correspondence may be addressed
(eddyzeng@gig.ac.cn).
Published online 3 August 2010 in Wiley Online Library
(wileyonlinelibrary.com).
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Environ. Toxicol. Chem. 29, 2010
regarding consumption rates for aquatic products from different
world regions were obtained from the database compiled
and maintained by the United Nations Food and Agriculture
Organization (FAO; http://faostat.fao.org/site/610/default.
aspx#ancor). The estimated daily intake (EDI) for PCDD/Fs
and DL-PCBs is calculated as EDI (pg toxic equivalent [TEQ]/
kg body weight [bw]/d), and is based upon aquatic consumption
(g/d) contaminant concentration (pg TEQ/g)/bw (60 kg for Asian
consumers and 70 kg for European, African, and American
consumers). The EDI for PCBs, OCPs, and PBDEs is calculated
as EDI (ng/kg bw/d), and is based upon aquatic product consumption (g/d) contaminant concentration (ng/g)/bw (60 kg for
Asian consumers and 70 kg for European, African, and American consumers), of which contaminant concentrations were
primarily derived from 50th and 90th percentile concentrations,
and utilizing mean concentrations whenever median values
were not available (Supplemental Data, Tables S1–S5).
Data comparison among groups was done using nonparametric
tests (Kruskal–Wallis H and Mann–Whitney U) with statistical
significance p < 0.05 under SPSS version 13.0.
Data analysis
Several guidelines have been established by different international organizations to assess POPs intake risk for human
health. These include the World Health Organization (WHO)specified tolerable daily intakes for dioxins plus dioxin-like
PCBs of 1–4 pg World Health Organization toxic equivalent
(WHO-TEQ)/kg bw/d [5]; the European Commission, Health
and Consumer Protection Scientific Committee on Food has
recommended a tolerable weekly intake for dioxins plus dioxinlike PCBs of 14 pg WHO-TEQ/kg bw/week (2 pg WHO-TEQ/
kg bw/d) [19]; the Korea Food and Drug Administration has
proposed a tolerable daily intake of 4 pg WHO-TEQ/kg bw/d
for dioxins plus dioxin-like compounds [20]; the United Kingdom Committee on Toxicity of Chemicals in Food, Consumer
Products and the Environment has proposed a tolerable daily
intake of 2 pg WHO-TEQ/kg bw/d [20]; and the Joint FAO/
WHO Expert Committee on Food Additives has recommended
a tolerable monthly intake of 70 pg WHO-TEQ/kg bw/month
(2.33 pg WHO-TEQ/kg bw/d) [21]. Regarding regulations for
intake of PCBs and OCPs, Health Canada has recommended a
tolerable intake level of 1,000 ng/kg bw/d for PCBs [22]. For
residues in edible commodities, the U.S. Food and Drug
Administration developed the action levels of 2,000 ng/g wet
weight for PCBs ([23]; www.epa.gov/ost/fishadvice/volume2/
index.html). China has established a maximum residue level for
DDTs (500 ng/g wet weight) and HCHs (100 ng/g wet weight)
([24];
http://down.foodmate.net/standard/sort/3/5949.html).
The European Union has established a maximum admissible
concentration of 50 ng/g wet weight for DDTs, 25 ng/g wet
weight for lindane, 10 ng/g wet weight for hexachlorobenzene
(HCB), and 10 ng/g wet weight for other HCH isomers [25].
The FAO/WHO has recommended acceptable daily intakes and
provisional tolerable daily intakes of 1.0 104 ng/kg bw/d and
5,000 ng/kg bw/d for DDTs and HCHs, respectively ([26];
http://www.who.int/ipcs/publications/jmpr/jmpr_pesticide/en/
index.html). The U.S. Environmental Protection Agency has
developed screening values (SVs) for contaminants such as
PCBs, OCPs, and PBDEs. These are defined as concentrations
of targeted analytes in fish and shellfish tissue which can be
used as threshold values to evaluate possible risk associated
with consumption of contaminated fish or seafood and to
H.-Y. Yu et al.
indicate that more intensive investigation should be conducted
[27,28]. The following equations are used to calculate SVs:
For noncarcinogens : SVn ¼ ðRfDBWÞ=CR
(1)
For carcinogens : SVc ¼ ð½RL=CSFBWÞ=CR
(2)
where SV is the screening value (mg/kg); BW is the body weight
(kg); CR is the consumption rate (kg/d); and RL is the maximum
acceptable risk level (10
5) ([27]; http://www.epa.gov/earth1r6/
6pd/qa/qadevtools/mod4references/supplemental/volume1.pdf).
The values for the oral reference dose (RfD; mg/kg/d) and the
oral cancer slope factor (CSF; mg/kg/d
1) are available online
at http://cfpub.epa.gov/ncea/iris/index.cfm?fuseaction ¼ iris.
showSubstanceList.
Hazard ratios (HRs) are calculated by dividing the average
daily exposure (EDI) by the screening values. A ratio greater
than unity indicates that the average daily exposure level
exceeds the SVs [29]. With respect to PBDEs, although several
authors have recently published toxicity data for PBDEs [30–
33], applicable risk assessment guidelines and regulations for
PBDEs are thus far quite limited. In the United States, the
Agency for Toxic Substances and Disease Registry (ATSDR)
has derived a minimal risk level of 3.0 104 ng/kg bw/d for
acute-duration oral exposure and 7,000 ng/kg bw/d for intermediate-duration oral exposure to lower brominated phenyl
ethers (BDEs), respectively. The ATSDR has also derived a
minimal risk level of 1.0 107 ng/kg bw/d for intermediateduration oral exposure to BDE-209 based on a no observable
adverse effect level of 1.0 109 ng/kg bw/d for developmental
toxicity in rats exposed to BDE-209 for 19 d during gestation
(http://www.atsdr.cdc.gov/mrls/index.html#bookmark02). Darnerud et al. have recommended a lowest observed adverse effect
level of 1.0 ¼ 106 ng/kg bw/d, based on the most sensitive
endpoints of toxic effects of PBDEs [34,35].
RESULTS AND DISCUSSION
Occurrence
Concentration levels of all the contaminants varied among
different regions and different types of aquatic products (Fig. 1).
Generally, levels of dioxins in marine fish, mollusks, crustaceans, and freshwater fish from Europe, and freshwater fish
from America, were higher than those in other regions. Marine
fish from Asia and Europe, and freshwater fish from America,
contained higher loadings of PCBs and OCPs; marine fish and
freshwater fish from America, Europe, and Asia showed higher
levels of PBDEs. Detailed concentration data are given in
Supplemental Data, Tables S1–S5. Some distribution patterns
associated with individual pollutant groups are described
below.
The highest level of dioxins was found in Saginaw Bay,
Michigan, USA. It was reported that this particular region
received many organic and inorganic materials from industrial
releases, as well as urban and agricultural runoff and domestic
sewage. Contaminants such as PCDDs, PCDFs, and PCBs in the
Saginaw Bay area have been shown to induce adverse environmental effects on local people and wildlife [36]. These results
are in general agreement with previously reported findings of
Wagrowski and Hites [37]. Marine fish samples from Frierfjorden, Norway also contained very high levels of PCDD/Fs. In
a situation somewhat similar to the industrial contamination at
Saginaw Bay, the Hydro Porsgrunn factory in Frierfjorden,
Norway discharged wastes containing high levels of PCDD/
PCDFs. It was estimated that the total amount of TEQPCDD/Fs
Review of dietary intake and health risk of POPs
Environ. Toxicol. Chem. 29, 2010
600
10
Concentration Level of PHCs
8
6
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Marine fish
Cephalopods
Mollusks
Crustaceans
Freshwater fish
Dioxins (pg TEQ/g ww)
OCPs (ng/g ww)
450
300
4
150
2
0
0
30
160
PCBs (ng/g ww)
PBDEs (ng/g ww)
25
120
20
15
80
10
40
5
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Af
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Eu
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0
Af
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Am a
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ic
a
0
Fig. 1. The 50th percentile concentrations of typical persistent organic pollutants in various types of aquatic products from each continent. Detailed data are
compiled in Supplemental Data, Tables S1–S5. Dioxins ¼ sum of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like PCBs;
OCPs ¼ organochlorine pesticides; PBDEs ¼ polybrominated diphenyl ethers; PCBs ¼ polychlorinated biphenyls; PHCs ¼ persistent halogenated
compounds; TEQ ¼ toxic equivalent. [Color figure can be seen in the online version of this article, available at wileyonlinelibrary.com.]
flowing into Frierfjorden was about 56 to 107 kg from 1951 to
1990 [38,39]. As a result, aquatic product consumption among
local residents had been constrained by PCDF/PCDD contamination [39].
The highest PCB level was found in freshwater fish samples
from four river basins located in the southeastern United States,
where industrial discharge from chemical manufacturing plants,
military facilities, pulp and paper mills, coal-fired power plants,
urban and agriculture runoff, mine drainage, and municipal
wastewater effluents had inevitably resulted in deterioration of
the environment around the four river basins [40]. Furthermore,
high levels of PCBs were also found in the livers of bluefin tuna
collected from coastal waters of Japan. Japan consumes more
tuna than any other country, about a quarter of the total annual
world tuna fishery resource (http://www.jsof.gov.cn/art/2008/8/
27/art_128_29752.html). Bluefin tuna farming was first developed in Japan in the 1970s [41]. These circumstances of species
preference and extensive tuna diet make it worthwhile to focus
further on contaminants in bluefin in Japan, together with
potential health risks from excessive human consumption. In
similar fashion, Ueno et al. [42] reported that high PCB concentrations were detected in livers of skipjack tuna collected
from offshore waters around Japan. The concentration levels of
PCBs in aquatic products collected from China were quite low
compared with those from other countries (Supplemental Data,
Table S3), which is in line with the fact that the amounts of
PCBs manufactured and used in China were relatively minor. It
was reported that China produced only 8,000 tons of PCBs
(0.6% of the total global production) during the1960s and 1970s
[43–44]. The United States consumed the largest quantity of
PCBs (46% of the total global consumption), followed by
Russia (7.9%), Germany (7.1%), Japan (4.1%), France
(4.1%), and Canada (3.1%), which consistently corresponds
to the residual levels of PCBs in aquatic products from these
countries (Supplemental Data, Table S3). In contrast, the highest PBDE level was found in freshwater fish samples from Lake
Mjøsa in Norway, probably due to the release of PBDEs into the
water from a textile manufacturer in the town of Lillehammer
[45]. Globally, the levels of OCPs in mussel samples collected
from the coast of the Egyptian Red Sea were significantly higher
than those from other regions, which may be attributed to the
use of large amounts of OCPs in this region [46]. It is also
important to note that relatively lower OCP residual levels
typically seen in biota samples from some tropical regions, such
as India and some African countries, do not necessarily equate
with less usage of OCPs in these regions. Rather, there are
indications that perhaps higher temperatures in these countries
facilitate more rapid volatilization and higher elimination rates
in biota [47,48].
Generally, all the contaminants in marine fish and freshwater
fish were more abundant than those in the other three types of
aquatic species, including cephalopods, crustaceans, and mollusks, except mollusk samples from China and Egypt (Fig. 1),
probably because of fish being at higher trophic levels and
having higher lipid contents than other aquatic species. The
levels of the contaminants under investigation were also different in developed and developing countries. Figure 2 shows that
the levels of dioxins (sum of PCDD/Fs and DL-PCBs), PCBs,
PBDEs, and OCPs were higher in industrialized countries than
those in less industrialized regions due to their special status as
by-products in industrial processes involving incineration,
chlorine bleaching of paper and pulp, and the manufacture
of some pesticides, herbicides, and fungicides [49], or large
amounts of usage in industrial production. This tendency has
been further confirmed by global pollution monitoring studies
of PCDD/Fs and DL-PCBs, in which comparatively higher
levels of these contaminants have been detected in highly
industrialized countries around the East and South China Seas
such as Japan, Korea, Taiwan, Hong Kong, and coastal China
[42]. By comparison, OCPs, because of their widespread
applications in agriculture and sanitation, exhibited certain
spatial distributional patterns. For example, in some developing
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Environ. Toxicol. Chem. 29, 2010
H.-Y. Yu et al.
patterns of the pollutants being sought. Except for some situations that are heavily influenced by the existence of pointsource pollution, levels of these persistent pollutants in aquatic
products tend to show a positive correlation with usage amount
in each country or continent. For example, the levels of PCDD/
Fs, PCBs, and PBDEs were higher in aquatic products from
industrialized countries than those from less industrialized
countries. Regarding OCPs, some developing countries had
also used large amounts of them; however, some more volatile
OCP constituents, such as HCBs and HCHs, are readily distilled
to colder regions, resulting in lower than expected levels in
aquatic products from tropical regions.
Dietary intake
Fig. 2. Mean concentration levels of typical persistent organic pollutants in
marine fish and freshwater fish from developed and developing countries.
Dioxins ¼ sum of polychlorinated dibenzo-p-dioxins and dibenzofurans and
dioxin-like PCBs; FF ¼ freshwater fish; MF ¼ marine fish; OCPs ¼
organochlorine pesticides; PBDEs ¼ polybrominated diphenyl ethers;
PCBs ¼ polychlorinated biphenyls; TEQ ¼ toxic equivalent.
countries such as India, China, and Egypt, large amounts of
technical hexachlorocyclohexanes (HCHs) have been used for
these purposes [50]. Certain OCPs, such as HCHs, are more
liable to undergo atmospheric transport due to their higher
values of Henry’s Law constant and vapor pressure.
On the whole, the levels of contaminants in aquatic products
are influenced by numerous factors, such as the nature of the
environments being sampled, the types of aquatic products
being investigated, and the different characteristics and usage
The estimated dietary intake based on median concentrations
(EDI50) for people from different regions was highly variable in
different types of aquatic products (Fig. 3 and Supplemental
Data, Tables S7–S11). Compared with the global distribution of
concentration levels of pollutants in aquatic products, the EDI
of pollutants for global populations showed some similarities,
e.g., EDI50 through marine fish and freshwater fish were relatively higher than those through other types of aquatic products. Pollutant intake via cephalopods for Japanese, mollusks
for Chinese, and crustaceans for Norwegian consumers were
also very high (Fig. 3). The definition of EDI suggests that EDI
depends not only on pollutant concentration in aquatic products
but also on consumption of different species of aquatic products
for people in each region. As shown in Figure 4, the correlation
coefficients between EDI50 and pollutant concentrations in
aquatic products and between EDI50 and fish consumption
varied widely for different pollutants. For example, the concentrations of OCPs and PCBs in marine fish and concentrations
of PCBs and PBDEs in freshwater fish were decisive factors in
determining pollutant intake for global populations ( p < 0.01
for EDI50 vs concentration and p > 0.01 for EDI50 vs consump-
5
12
Dioxins (pg TEQ/kg bw/d)
OCPs (ng/kg bw/d)
4
3
Estimated Daily Intake
9
Marine fish
Cephalopods
Mollusks
Crustaceans
Freshwater fish
2
6
3
1
0
0
2.0
40
PCBs (ng/kg bw/d)
PBDEs (ng/kg bw/d)
1.6
30
1.2
20
0.8
10
0.4
ia
Eu
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Af
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Fig. 3. Estimated daily intake of typical persistent organic pollutants via various types of aquatic products for global consumers based on the 50th percentile
concentrations compiled from the major aquaculturing countries. Dioxins ¼ sum of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like PCBs;
OCPs ¼ organochlorine pesticides; PBDEs ¼ polybrominated diphenyl ethers; PCBs ¼ polychlorinated biphenyls; TEQ ¼ toxic equivalent. Detailed data are
given in Supplemental Data, Tables S7–S11. [Color figure can be seen in the online version of this article, available at wileyonlinelibrary.com.]
Environ. Toxicol. Chem. 29, 2010
1.2
70
0.000
0.005
0.000
0.004
0.001
0.8
0.459
0.01
0.000
0.002
60
0.304
0.045
0.6
0.2
0.4
0.2
0.0
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CP OC
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Fig. 4. The correlation coefficients between 50th concentrations of different
chemicals in marine and freshwater fish and estimated daily intake for global
consumers derived from 50th concentration levels in samples. The value
at top of each column is the value for statistical significance p. Filled
bars ¼ estimated dietary intake based on median concentrations (EDI50)
versus concentration; open bars ¼ EDI50 versus consumption. Dioxins ¼ sum
of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxinlike PCBs; OCPs ¼ organochlorine pesticides; PBDEs ¼ polybrominated
diphenyl ethers; PCBs ¼ polychlorinated biphenyls.
tion). In contrast, both the concentrations and consumption
levels of OCPs in freshwater fish, dioxins in marine and freshwater fish, and PBDEs in marine fish were equally important in
determining their intakes for people ( p < 0.01 for both EDI50 vs
concentration and consumption).
The EDI50 values of DL-PCBs and PCDD/Fs through consumption of marine fish and crustaceans collected from Frierfjorden, Norway were much higher than those from other
regions. As discussed above, this region had very significant
point-source pollution from PCDDs, PCDFs, and PCBs, which
has resulted in recommendations that people should limit their
consumption of fish [36]. Consumption of marine fish and
crustaceans by Norwegian people is at the high end of the
global range (Supplemental Data, Table S6). Similarly, the
highest exposure level for PCBs was found in Japan’s consumers via marine fish collected from Japanese coastal waters,
which was also due to high PCB concentrations and large
marine fish consumption for the Japanese population [51].
Among all species of aquatic products, PBDE intake through
marine and freshwater fish for global populations was much
higher, which can be ascribed to higher marine and freshwater
consumption rates on a global scale. According to statistics data
by the FAO of the United Nations, the total production of
marine fish and freshwater fish in 2007 amounted to 6.76 107
and 4.06 107 tons, accounting for 48 and 29%, respectively, of
total aquaculture production. The highest PBDE intake was, for
Norwegians, via consumption of freshwater fish collected from
Lake Mjøsa, Norway, which was also attributed to point-source
pollution. Because China has the largest fishery production in
the world and a long history of OCP usage, the Chinese
population is exposed to the highest level of OCPs through
consuming mollusks.
Figure 5 shows the EDI50 values for all the target analytes
and aquatic products on the continent level. As discussed above,
the daily intake correlated with both the concentrations of POPs
6
Africa
America
Asia
Europe
Oceania
0.006
EDI50 (ng/kg BW/day)
Correlation coefficient r
1.0
0.002 0.002
0.000
50
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5
4
40
3
30
2
20
1
10
EDI50 (pg TEQ/kg BW/day)
Review of dietary intake and health risk of POPs
0
0
PCBs
PBDEs
OCPs
Dioxins
Fig. 5. The total estimated daily intakes of typical persistent organic
pollutants via consumption of aquatic products based on the 50th percentile
concentrations for each continent. bw ¼ body weight; dioxins ¼ sum of
polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like PCBs;
EDI50 ¼ estimated dietary intake based on median concentrations;
OCPs ¼ organochlorine pesticides; PBDEs ¼ polybrominated diphenyl
ethers; PCBs ¼ polychlorinated biphenyls; TEQ ¼ toxic equivalent.
and consumption rates of aquatic products. Generally, Europeans uptake more dioxins than people in other continents
(Fig. 5). Asians and Americans are exposed to higher levels
of PCBs and OCPs via aquatic product consumption than other
populations (Fig. 5). It is noteworthy that the uptake levels of
PBDEs are all extremely low for all global consumers compared
with those of other pollutants, which was previously attributed
to the possibility that large portions of PBDEs used as ingredients of brominated fire retardants may have remained in
currently used and/or disposed commercial products [52]. African people, in general, uptake very small amounts of POPs
through aquatic products probably because they consume small
quantities of aquatic products and the loadings of POPs are low
in Africa. It should be noted that intakes of the sum of PBDEs,
PCBs, and OCP via marine fish, cephalopods, mollusks, crustaceans, and freshwater fish account for 55.8, 13.6, 7.4, 0.8, and
22.4%, respectively, of the total intake (Fig. 6), indicating that
consumption of marine fish is the predominant route of human
exposure to these contaminants.
Risk assessment
Compared with the criteria for DL-PCBs and PCDD/Fs,
EDI50 and EDI90 (except intakes via mollusks for people in
France) for dioxins in all types of aquatic products except
marine fish were lower than 4 pg WHO-TEQ/kg bw/d. Due
to high residues of dioxins and high consumption of marine fish,
human exposure to dioxins via marine fish was higher than that
through other aquatic products. The EDII50 and EDI90 of dioxin
intakes via marine fish were in the range of 0.07 to 12.8 and 0.13
to 43.8 pg WHO-TEQ/kg bw/d, with mean values of 2.6 and
9.1 pg WHO-TEQ/kg bw/d, respectively. Furthermore, 53% of
EDI90 were higher than 4 pg WHO-TEQ/kg bw/d. Exposure to
PCDD/Fs and DL-PCBs through aquatic products, excluding
marine fish, for most people in the world is in the range of levels
lower than 4 pg WHO-TEQ/kg bw/d. Nevertheless, dioxin
intakes via marine fish should be taken seriously especially
for people in Norway and France. As for OCPs and PCBs, the
non-cancer hazard ratio (HRn) and cancer hazard ratio (HRc)
based on the 50th and 90th percentile concentrations of OCPs
(except HRc based on the 90th percentile concentration (1.5) for
Chinese people via freshwater fish) were much lower than one,
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Environ. Toxicol. Chem. 29, 2010
H.-Y. Yu et al.
Fig. 6. Contribution of various types of aquatic products to total intake of
persistent. halogenated compounds.
indicating minimum risk from exposure to OCPs through
aquatic products. Additionally, the levels of DDTs and HCHs
in most samples, except bivalves collected from Egypt, were all
lower than the limits set by the Chinese government (600 ng/g
wet weight) and FAO/WHO (15,000 ng/kg bw/d) for the sum of
DDTs and HCHs. Additionally, 4.2 and 40% of the samples
studied had levels lower than the European Union limit (85 ng/g
wet weight) based on the 50th and 90th percentile concentrations, respectively. However, the mean values of the HRn and
HRc for PCBs were 0.68 and 1.3 from the 50th percentile
concentration, and 2.7 and 5.2 from the 90th percentile concentration, indicating that there is some cancer risk for humans
due to PCBs intake through consumption of aquatic products
(Fig. 7). However, if marine fish were excluded from the
assessment, the mean values of HRn (50th percentile: 0.05;
90th percentile: 0.19) and HRc (50th percentile: 0.20, 90th
percentile: 0.77) were lower than one, suggesting that higher
hazard risk was derived from marine fish compared with other
types of aquatic products. In contrast, the levels of PCBs were
far below the limits of 1,000 ng/kg bw/d set by Health Canada
and the maximum level of 2,000 ng/g wet weight set by the U.S.
Food and Drug Administration. The HRn values for PBDEs
were all several orders of magnitude lower than one, and the
estimated daily intakes of PBDEs compiled herein were all
much lower than the limits described above, including minimal
risk level for acute-duration oral exposure (3.0 104 ng/kg bw/d),
intermediate-duration oral exposure to lower brominated
phenyl ethers (BDEs) (7,000 ng/kg bw/d), and intermediateduration oral exposure to deca BDE (1.0 107 ng/kg bw/d)
developed by the ATSDR, and the lowest observed adverse
effect level (1.0 106 ng/kg bw/d) recommended by Darnerud
et al. (Supplemental Data, Table S10). In all, health risk is
minimal for PBDEs intake via aquatic consumption based on
the current regulations and guidelines.
Generally speaking, risk derived from dioxins, OCPs, and
PBDEs through consumption of aquatic products (excluding
marine fish for dioxins) is in the acceptable level against
existing criteria. In contrast, risk derived from dioxins through
consumption of marine fish is relatively higher and may cause
hazard to consumers, especially to people in Norway and
France. Polychlorinated biphenyls might pose threats to human
health via aquatic products, particularly marine fish consumption, based on cancer and noncancer hazard ratio assessment.
The health risk assessment based on concentration levels and
consumption data from each country is not definitive because
concentration data were limited and consumption data were
largely out of date. Furthermore, numerous guidelines and
regulations related to human health risk assessments, which
are somewhat variable, have been set by different organizations
and governments. Therefore, the assessment results based these
Fig. 7. Non-cancer (HRn) and cancer (HRc) hazard ratios of polychlorinated
biphenyls (PCBs) derived from the 50th and 90th percentile concentrations.
Mean hazard ratio was used for countries with more than one set of data
available.
criteria are mostly qualitative and intended to provide general
trends only.
Total amount of PHCs in global aquatic products
The total amounts of persistent halogenated compounds
(PHCs), sum of PCBs, OCPs, and PBDEs annually accumulated
in global aquatic products were estimated based on the 50th and
90th percentile concentrations compiled in this review, and
the total fishery production data of 2007 in each continent,
available at http://www.fao.org/fishery/statistics/software/
fishstat/en (Supplemental Data, Table S12). The total amounts
accumulated in global aquatic products are 2.1 and 5.6 tons/year
for PCBs, 0.21 and 0.96 tons/year for PBDEs, and 4.7 and
12.8 tons/year for OCPs, based on the 50th and 90th percentile
concentrations, respectively. Therefore, the amounts of PHCs
accumulated in global aquatic products were 7.0 and 19.4 tons/
year from the 50th and 90th percentile concentrations. The
amounts of PHCs in aquatic products from Asia, America,
Europe, Africa, and Oceania account for 75.3, 14.5, 7.6, 2.4,
and 0.15% of the global total based on the 50th percentile
concentration. It is interesting to note that the total global
amount of PBDEs used in 2001 alone was approximately
67,390 tons [53], and the amounts of PCBs and sum of DDTs
and HCHs used were 1,200,000 and 16,800,000 tons, respectively [54,55], indicating that the amount of PHCs stored in
aquatic products appears to be an extremely small fraction of the
total present in the environment. Other environmental media or
Review of dietary intake and health risk of POPs
even commercial products, such as electronics and furniture,
may contain vast amounts of PHCs. For example, electronic
waste still holds the majority of PBDEs ever produced [56].
CONCLUSION
Generally, the levels of dioxins, PCBs, OCPs, and PBDEs in
aquatic products are somewhat consistent with the amounts of
these compounds used in each country or continent. As byproducts in industrial processes or industrial chemicals, PCDD/
Fs, DL-PCBs, PCBs, and PBDEs were all quite abundant in
aquatic products from industrialized countries such as Norway,
Spain, the United States, and Canada. With respect to OCPs,
because they have been used abundantly in agriculture and
sanitation in some developing countries such as China, India,
and Egypt, levels of OCPs were also considerably high in
aquatic products from developing countries. Estimated daily
intakes of PCDD/Fs, DL-PCBs, OCPs, and PBDEs for global
residents through consumption of aquatic products (excluding
marine fish for dioxins) are in the acceptable range against
existing regulations and guidelines, with the following descending magnitude of exposure: first, Europeans > Asians >
Americans > Oceanians > Africans for the sum of PCDD/Fs
and DL-PCBs; second, Asians > Americans > Europeans >
Oceanians > Africans for OCPs; and third, Americans >
Europeans > Asians for PBDEs. In contrast, dietary intake of
PCBs through aquatic product consumption, especially via
marine fish, appears to be at sufficiently high levels to cause
cancer risk for global consumers, with the exposure levels
following the order of Asians > Europeans > Americans >
Oceanians. It should be noted that although the levels of PCBs
and OCPs in recent years have shown a declining trend in the
general environment [57–60], obvious fresh inputs exist in
some regions around the world [40,51,61–65], which merits
greater awareness and attention. Furthermore, we suggest that
all countries should strive, on a more global scale, to better
harmonize their various regulations and guidelines for these
ubiquitous pollutants, in order to allow the development of more
comprehensive and accurate risk assessment models, as well as
dietary exposure pathways, for protecting public health.
SUPPLEMENTAL DATA
Table S1. Levels of PCDD/Fs.
Table S2. Levels of DL-PCBs.
Table S3. Levels of PCBs.
Table S4. Levels of PBDEs.
Table S5. Levels of OCPs.
Table S6. Consumption of aquatic products for global
consumers.
Table S7. Estimated daily intake of PCDD/Fs.
Table S8. Estimated daily intake of DL-PCBs.
Table S9. Estimated daily intake and cancer and noncancer
hazard ratio for PCBs.
Table S10. Estimated daily intake and non-cancer hazard
ratio for PBDEs.
Table S11. Estimated daily intake and cancer and noncancer
hazard ratio for OCPs.
Table S12. The total amounts of dioxins, PCBs, OCPs, and
PBDEs stored in global aquatic products. (338 KB DOC)
Acknowledgement—Financial support for the present study was provided by
the National Natural Science Foundation of China (40821003, U0633005,
and 40588001). Thanks also go to Michael Watson for his input to, and
technical editing of, the manuscript. This is contribution IS-1239 from
GIGCAS.
Environ. Toxicol. Chem. 29, 2010
2141
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