Human Exposure to Brominated Flame Retardants - ACS Publications

Chapter 2

Human Exposure to Brominated Flame Retardants Downloaded by UNIV OF IDAHO on December 12, 2016 | http://pubs.acs.org Publication Date (Web): December 7, 2016 | doi: 10.1021/bk-2016-1243.ch002

Boris Johnson-Restrepo*,1 and Aída L. Villa2 1Chemistry

and Environmental Research Group, School of Exact and Natural Sciences, San Pablo Campus, University of Cartagena, Cartagena 130015, Colombia 2Environmental Catalysis Research Group, Chemical Engineering Department, Engineering Faculty, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia *E-mail: [email protected]

The aim of this chapter is to examine the human exposure to brominated flame retardants (BFRs) such as polybrominated bisphenyl ethers (PBDEs), hexabromocyclohexane (HBCDs), and tetrabromobisphenol A (TBBPA). BFRs have been measured in several types of samples including adipose tissue, blood, and breast milk. PBDE concentrations from the U.S. population are the highest at 10 to 100-times greater than those reported for the rest of the world. HBCDs and TBBPA concentrations in the U.S. population are lower than the concentrations found in Europe. These exposure differences among different countries were explained by the usage pattern and market demand for BFRs. Several pathway contribute to human body burmen such as food daily intake, dust, and indoor/outdoor air. While Dust and food ingestion are considerated the important contribution to PBDE exposure in adults, breast milk intake is the principal source of exposure to infants.

© 2016 American Chemical Society Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.

Downloaded by UNIV OF IDAHO on December 12, 2016 | http://pubs.acs.org Publication Date (Web): December 7, 2016 | doi: 10.1021/bk-2016-1243.ch002

Introduction Brominated flame retardants (BFRs) are incorporated into polymers as additives or are bonded chemically through a reaction, for the purpose of reducing the flammability of the materials to reach established fire safety standards (1). BFRs have been used widely in industrial and consumer products since the 1970s with a global annual growing of 4-5%. The worldwide market of BFR in 2011 was estimated at 394,000 metric tons (19.7 %) (www.flameretardants-online.com). BFRs are contained in different polymers such as polyurethane, epoxy resins, polyolefins, polyamides, high impact polystyrene foam, acrylonitrile–butadiene–styrene (ABS), polyurethanes, polycarbonate, styrene copolymers, polyterephthalate, and polyvinyl chloride; these polymers are extensively used in several consumer products including building materials, electronics, carpets, upholstery textile, and car panels (2). Polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and hexabromocyclododecanes (HBCDs) were the most widely BFRs used. PBDEs have been commercially produced as penta-BDE, octa-BDE, and deca-BDE technical mixtures (3). Several of the BFR compounds are persistent and bioaccumulative and have become ubiquitous environmental pollutants. PBDEs have been detected in environmental samples since the 1970s (4–7). However, earlier measurements of PBDEs in environmental samples were not isomer-specific because standards were not available until the late 1990s. Örn and coworkers synthesized selected PBDE congeners for isomer-specific analysis for environmental samples and toxicity evaluation (8–10). In addition, it was estimated that PBDE concentrations in Swedish breast milk had increased by 60 fold with a doubling time of 5 years (9). Several other studies have showed the occurrence of PBDEs in a variety of environmental and biological samples. Now, PBDEs are considered ubiquitous due to these compounds are being present in all environmental media including air (11, 12). soil (12), water (13), sediments (14, 15), foodstuffs (16–18), dust (19, 20), wildlife (21, 22), and humans (9, 23–28). PBDEs have been detected in remote areas such as the Arctic (29, 30), and the Antarctic (31–33). BFRs have been reported to elicit toxic effects in model animal studies (34–36).

Brominated Flame Retardants Brominated flame retardants (BFRs) are synthetic organobromide chemicals that have been incorporated into many flammable materials in order to provide longer escape times in case of fire, thus saving lives as well as reducing the damages from the fire. The use of BFRs had been mandated by law in several countries, especially in furnishings used in public places such as cinema theaters (37). Chemicals that have been the most widely used as BFRs include polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), hexabromocyclododecanes (HBCDs), polybrominated biphenyls (PBBs), and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). BFRs are classified into two broad categories, based on their usage, as ‘additive’ or ‘reactive’. Additive BFRs are incorporated into the mass of polymers or materials whereas the reactive 18 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.


BFRs are linked covalently to the chemical structure of polymers. Thus, there is a reduced leaching or release of reactive BFRs from source materials into the environment. However additive BFRs are not strongly bound to the matrix and therefore can be leached or released easily from the substrate. BFRs have a characteristic inhibitory effect on combustion and thus make the materials that contain them resisting to flammability. Bromine atoms present in BFRs generate bromine radicals (Br•) at elevated temperatures due to poor thermal stability. These radicals interrupt the propagation of free radical reactions involved in the flame by suppressing the high-energy and exothermic free radicals (hydrogen, H• and hydroxyl, OH•) formed in the gas phase. As a consecuense, radical free species (H• and OH•) are not propagated in the combustion and are reemplaced by less reactive radical species (R•) and thus the fire of materials containing flame retards are slowed, suppressed or eventually extinguished (Figure 1) (38).

Figure 1. Mechanism of action of brominated flame retardants. Although BFRs have beneficial roles when used in several materials including plastics, rubbers, textiles, and building materials, by imparting fire resistance, these chemicals present toxic, persistent and bioaccumulative effects as the organochloride contamiants previously reported (39). Furthermore, some BFRs have occured in various environmental media, wildlife, and human tissues throughout the world showing that they are widespread in the environment (2, 3, 40, 41). BFRs have also been reported to occur in fish from open oceans and in marine mammals (42, 43).

Polybrominated Diphenyl Ether (PBDEs) PBDEs are syntetic organic compounds that have been used as additive BFRs, and resemble polychlorinated biphenyls (PCBs) in their chemical structures. Also PBDEs and their metabolites are structurally similar to thyroid hormones (THs) (Figure 2). PBDEs are diphenyl ether substituted with bromine atoms at different positions resulting in 209 theoretically possible congeners. The general chemical formula for PBDEs is C12H10-nOBrn, (n = 1, 2,..,10). There are 10 homologues of PBDEs depending on the degree of bromination (Table 1). The chemical structure of THs (triiodothyronine, T3 and thyroxine, T4) contains a diphenyl ether backbone but is substituted by iodine instead of bromine. Iodine 19 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.


substitutions on the dipheyl ether ring for T3 and T4 are at the positions 3, 3′, 5 and 3, 3′, 5, 5′, respectively. Additionally, T3 and T4 contain one OH group at the 4′ position and an alanine residue. PBDEs were produced as three types of technical penta-BDE, octa-BDE, and deca-BDE mixtures. The penta-BDE mixture contains tri-BDEs, tetra-BDEs (mainly BDE-47), penta-BDEs (mainly BDE-99 and BDE-100) and hexa-BDEs (BDE-153 and BDE-154); the octa-BDE mixture contains hexa-BDEs, hepta-BDEs (BDE-183), octa-BDEs (BDE-203), nona-BDEs, and BDE-209; and the deca-BDE mixture comprises primarily BDE-209 (~96%) and small amounts of nona-BDEs (Table 1).

Figure 2. Chemical structures of polybrominated diphenyl ether (PBDEs) (x and y are atoms of bromide, x+ y ≤ 10) and thyroid hormones.

20 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.

Table 1. Brominated diphenyl ether homologues


Homologues Formula

Homologues Name

Abbreviation

Molecular Weight

No. of Congeners

C12H10O

Biphenyl ether

BDE

170.2

1

C12H9OBr

Monobromodiphenyl ether

MonoBDE

249.1

3

C12H8OBr2

Dibromodiphenyl ether

DiBDE

328.0

12

C12H7OBr3

Thribromodiphenyl ether

ThriBDE

406.9

24

C12H6OBr4

Tetrabromodiphenyl ether

TetraBDE

485.8

42

C12H5OBr5

Pentabromodiphenyl ether

PentaBDE

564.7

46

C12H4OBr6

Hexabromodiphenyl ether

HexaBDE

643.6

42

C12H3OBr7

Heptabromodiphenyl ether

HeptaBDE

722.5

24

C12H2OBr8

Octabromodiphenyl ether

OctaBDE

801.4

12

C12H1OBr9

Nonabromodiphenyl ether

NonaBDE

880.3

3

C12OBr10

Decabromodiphenyl ether

PentaBDE

959.2

1

Technical mixtures have been sold under different trade names. The penta-BDE mixture is known as Bromkal 70-5DE and DE-71; the octa-BDE mixture as Bromkal 79-8DE and DE-79; and the deca-BDE mixture as DE-83R and Satex 102E. The technical mixtures differ in their compositions of specific BDE congeners. The technical mixtures differ in their composition of specific BDE congeners and have been characterized in detail (Table 2) (44–46). The penta-BDE mixture has been mainly used in polyurethane foam (for furniture at levels as high as 30% by weight) in upholsteries, carpet, and insulation panels, whereas the octa-BDE mixture has been used in rigid plastics such as acrylonitrile-butadiene-styrene (ABS) in applications such as electronic goods and appliances. The deca-BDE mixture is used in plastics, including high impact polystyrene for electrical and electronic equipment (televisions, cars, pipes, cables, and wires), polypropylene, poly(butylene terephthalate), unsaturated polyesters, and nylon, as well as in textiles for furniture.


Mixture Penta-BDE

Commercial name DE-71

Bromine atoms (x + y)

IUPAC

3

28

2,4,4′-tri-BDE

0.37

4

47

2,2′,4,4′-tetra-BDE

33.0

49


0.77

66


1.02

85

2,2′,3 4,4′-penta-BDE

3.18

99

2,2′,4,4′,5-penta-BDE

42.5

100

2,2′,4,4′,6-penta-BDE

10.9

102

2,2′,4,5,6′- penta-BDE

0.13

138

2,2′,3,4,4′,5′-hexa-BDE

0.24

139

2,2′,3,4,4′,6- hexa-BDE

0.16

153

2,2′, 4,4′,5,5′-hexa-BDE

3.75

154

2,2′, 4,4′,5,6′-hexa-BDE

3.00

155

2,2′,4,4′,6,6′- hexa-BDE

0.32

138

2,2′,3,4,4′,5′-hexa-BDE

0.6

153

2,2′, 4,4′,5,5′-hexa-BDE

8.7

154

2,2′, 4,4′,5,6′-hexa-BDE

1.1

171

2,2′,3,3′,4,4′,6-hepta BDE

1.8

5

22


Table 2. Specific congener composition of PBDE mixtures

6

Octa-BDE

DE-79

6

7

Chemical Name

Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.

Concentration (% w/w)

23


Mixture

Commercial name

Bromine atoms (x + y)

Concentration (% w/w)

2,2′,3,4,4′,5,5′-hepta-BDE

1.7

183

2,2′,3,4,4′ 5′,6-hepta BDE

42.0

196

2,2′,3,3′,4,4′,5,6′-octa-BDE

10.5

197

2,2′,3,3′,4,4′,6,6′-octa-BDE

22.2

203

2,2′,3,4,4′,5,5′,6-octa-BDE

4.4

206

2,2′,3,3′,4,4′,5,5′,6-nona-BDE

1.4

207

2,2′,3,3′,4,4′,5,6,6′-nona-BDE

11.5

10

209

2,2′,3,3′,4,4′,5,5′,6,6′-deca-BDE

1.3

9

206

2,2′,3,3′,4,4′,5,5′,6-nona-BDE

2.2

207

2,2′,3,3′,4,4′,5,6,6′-nona-BDE

0.2

208

2,2′,3,3′,4,5,5′,6,6′-nona-BDE

0.1

209

2,2′,3,3′,4,4′,5,5′,6,6′-deca-BDE

96.8

9

Saytex 102E

Chemical Name

180

8

Deca-BDE

IUPAC

10


Tetrabromobisphenol A (TBBPA)


TBBPA is a reactive flame retardant used principally in the circuit boards of electronic goods (e.g., television sets, computers, printers, photocopiers, fax machines, mobile phones) and electrical equipment (e.g., washing machine, dryers) (Figure 3). TBBPA is covalently bound to epoxy resins but in some cases, this is used as a additive BFR on acrylonitrile-butadiene-styrene polymers.

Figure 3. Chemical structures of tetrabromobisphenol A (TBBPA).

Hexabromocyclododecane Isomers (HBCDs) HBCDs are used mainly in expandable and extruded polystyrene foam for thermal insulation, textile coating for upholstery furniture, and high impact polystyrene for electrical and electronic consumer goods (www.bsef.com). HBCD (Figure 4) consists of a non-aromatic ring of 12 atoms, of which 6 asymmetric carbons in the positions of 1, 2, 5, 6, 9, and 10, resulting in 16 possible diastereoisomer structures. There are eight HBCD diastereoisomers found in the technical HBCD mixture, comprising 3 pairs of racemic enantiomers of (±) α- (11.8%), (±) β- (5.8%), and (±) γ- (81.6%) isomers and two meso forms of δ- (0.5%) and ε- (0.3%) isomers (47). When the HBCD technical mixture is heated at temperatures of between 160 and 200°C, α-HBCD prevails due to thermal stereoisomerization of the γ- and β- HBCD isomers (48).



Figure 4. Steroisomer structure of hexabromocyclododecane (HBCDs) (47).



Human Exposure to PBDEs PBDEs have been used in large volumes (up to 30% by weight) in many consumer products and have become ubiquitous pollutants in all environmental compartments, including wildlife and humans. PBDEs became the contaminants of interest among environmental scientists and regulators after earlier studies in the 1990s showed an exponential increase in concentrations in breast milk. The first report was published using breast milk samples from Sweden population. Results showed that PBDE concentrations haven been increasing exponentially with a doubling time every 5 years over a period of 25 years since the 1970s (9). Concentrations of PBDEs in North American human samples were also shown to increase exponentially (2, 49) but increasing concentrations have been also reported in China (50, 51). Therefore, PBDEs have been regarded as a new type of persistent organic pollutants (POPs), similar to PCBs, and the concerns regarding these contaminants are mounting due to the potential impact on human health that these chemicals may pose if the exposure levels and body burdens continue increasing. Although PBDEs can affect thyroid hormone levels in animal models, the levels at which such effects would occur in humans are also reported (52). The mechanisms by which PBDEs cause thyroid dysfunction are not clearly understood. However, PBDEs and their hydroxylated metabolites are structurally similar to THs, as mentioned earlier, and these chemicals can alter the transport of THs, or can directly interact with the thyroid gland (53). Alterations in the homeostasis of THs during the first three months of prenatal development can carry latent effects in the early stages of brain development in neonates. The rising concentrations of PBDEs, their environmental persistence, and the high bioaccumulation potential (similar to that for PCBs and DDTs) in biota and human tissues, resulted in a voluntary phase-out or ban on the usage of penta-BDE and octa-BDE mixtures in Europe and the U.S. Although the concentrations and frequency of detection of decabrominated diphenyl ethers (BDE-209) have been low in biological samples, high and increasing concentrations have been found in environmental abiotic samples (sludge, dust, food, air, soil, water, and sediment). It has been suggested that BDE-209 could be debrominated to more toxic lower-polybrominated diphenyl ether congeners by photolytic, thermal (54) or microbiological processes (55–57). Therefore, the lower brominated congeners will remain in the environment and human exposures will continue to occur in the near-future. Furthermore, products containing PBDEs are still in use and they will continue to be a source of human and environmental exposures. Nevertheless, some important advances in regulations have taken place in Europe and in the Unitted States, including banning or restrictions of manufacturing and use of PBDEs, including the deca-BDE mixture.



Exposure Pathways, Bioaccumulation, Storage, and Excretion Models of BFRs The body burdens of brominated flame retardants occurs by exposure from different sources and physicochemical properties of these chemicals. BFRs, as other organohalogen compounds (DDT, PCBs, PCDDs, etc.), are lipophilic and non-ionized at physiological pH. Thus they readily penetrate cellular barriers and establish a dynamic equilibrium between the blood and adipose tissues which are stored in the body. Storage of these chemicals in adipose tissue is considered as a mechanism of protection to keep the chemicals away from important target organs. The metabolism and elimination of BFRs from the body is slow. For the general population, a lifelong exposure brings consequence to a gradually increasing concentration of the chemicals in the organism. Elimination half-lives of the chemicals from the biological lipid deposits are on the order of several years. However, in females, chemical may again be transported to the blood during the lactactation, making this period the most important route of elimination for such chemicals (Figure 5). Brominated retardant such as PBDEs in.the U.S. general population are much higher than the body burdens reported from the populations in other parts of the world (2, 40, 41). Estimates of daily dietary intake of PBDEs did not appear to be a major pathway of exposure to PBDEs (58–61) (Figure 6).

Figure 5. Exposure pathway, bioaccumulation, storage, and excresion model for organohalogens (BFRs).



Figure 6. Important human exposure pahways to BFRs.

Human Biomonitoring of PBDEs A global review of literature on PBDEs in human tissue samples was performed to evaluate the current knowledge and to identify data gaps. In this review, only the research papers that report specific PBDE congener concentrations were selected. For comparison, concentrations were normalized by converting the data to a lipid weight basis, because PBDEs are lipophilic and their concentrations are expected to be proportional to the lipid content in tissues. Furthermore, a geometric mean or median concentrations of specific congeners and total PBDEs (∑PBDE) were used or calculated from the raw data reported. If the year of sampling was not reported on the publication, it was 28 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.


assumed as two years prior to the publication date of the paper. Data reported in the literature are not homogeneous, because much of the data are on congeners found in the penta-BDE mixture, including BDE-47, 99, 100, 153, and 154, and the octa-BDE mixture such as BDE-183 and 203. BDE-209, which is the major component of the deca-BDE mixture, was not included in the studies conducted before 2000. There were difficulties in accurately quantifying BDE-209 in environmental and biological samples using the currently available techniques (62). In addition, it was thought that BDE-209 was degraded to lower brominated congeners in the environment and in biological tissues (54–56). Median or geometric mean concentrations were used in this review, because of their central tendency in the measurement of distributions; furthermore, the environmental data are predominantly log-normally distributed. However, the values of median and geometric mean are almost similar because in a log-normal distribution, the geometric mean is the estimation of the true median (63, 64). Studies of human biomonitoring of PBDEs has provided valuable information on sources of exposures and exposure patterns and the biomonitoring has been accomplished through an array of human matrices, including breast milk, adipose tissues, breast tissue, liver, serum, whole blood, cord blood serum, and placenta. PBDE concentrations are tabulated by congener and the sum of congeners reported by several authors (Table 3).

Adipose Tissue Concentrations of lipophilic organohalogen contaminants, such as PBDEs, in the body are in a dynamic equilibrium between blood and adipose tissue. Concentrations in the adipose tissue reflect the levels of chemical in the body after reaching a steady state. Concentrations in the other tissues depend on the lipid dynamics and storage in the adipose tissue. Concentrations in blood reflect the most recent exposure which can be affected by the ingestion of a recent meal containing the chemical residue in question, inhalation or dermal absorption of the chemicals in proximity of contaminated hazardous sites. Adipose tissue samples contain, on average, over 60% of lipid, and store high levels of lipophilic contaminants; thus, adipose tissue analysis has the advantage over other human tissue samples because a bench-top gas chromatograph with a low resolution quadrupole mass spectrometric detector (GC-MS) is adequate to detect all brominated and chlorinated contaminants. However, adipose tissue samples can only be obtained by invasive techniques, which is a major limitation. Interestingly, one way of obtaining adipose tissue is from waste products of cosmetic surgeries. Recently, liposuction techniques have become popular among healthy overweight people who want to lose weight by removing excessive fat stored in the body. Access to and use of such samples would help in understanding the accumulation of contaminants in a fraction of the total population. Collection of information from several biomonitoring studies on PBDEs in the general population showed widespread global contamination by these compounds (3, 40, 41, 65–67). Stanley et al. detected hexa- to deca-PBDE homologues in U.S. adipose tissues samples collected in 1987 by the National 29 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.


Human Adipose Tissue Survey (NHATS). This study was a first report on PBDEs in human tissues from the U.S. Median concentrations were: hexa-BDEs, 0.02 ng/g lipid wt (range, < LOD – 1 ng/g lipid wt), hepta-BDEs, 0.1 ng/g lipid wt (range, 0.001 – 2 ng/g lipid wt), octa-BDEs, 0.2 ng/g lipid wt (range, < LOD – 8 ng/g lipid wt), nona-BDE, detected but not quantified, and deca-BDE, < LOD to 0.7 ng/g lipid wt. Median concentrations of sum of hexa- to octa-BDE was 0.49 ng/g lipid wt (range, 0.003 to 0.83 ng/g). It should be noted that concentrations of specific BDE congeners were not reported due to the lack of appropriate standards at that time. This study suggested that people from the U.S. in the late of 1980’s were exposed at low levels of octa-BDE and deca-BDE mixtures. Beginning the new millennium, several studies in the U.S. reported PBDE concentrations by specific congeners including BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154. BDE congener 47 is generally the most prevalent compound in adipose samples. She et al. (23) measured BDE-47, 99, 100, 153, and 154 congeners in adipose tissue samples from 23 women from California collected during 1996-1999. BDE-47 was the predominant congener in all samples. The PBDE congener profile was 42% BDE-47, 13% BDE-99, 8% BDE-100, 15% BDE-153, and 22% BDE-154. BDE-154 was dominant in 3 of 23 women. The median concentration of BDE-47 was 18.3 ng/g lipid wt (range, 7.01 to 196 ng/g lipid wt) and ∑BDEs was 41.4 ng/g lipid wt (range, 17.2 to 462 ng/g lipid wt). PBDE concentrations found in paired abdominal and breast adipose tissue samples were similar and statistically correlated. The study group also included samples with malignant tumor conditions (n=12), ductal carcinomas in situ (DCIS) (n=3) and benign tumor conditions (n=8). Concentrations of the ∑BDEs and specific congeners were not related to the disease status of malignancies (malignant or DCIS) of the individuals. However, ∑BDE concentrations were correlated negatively with age. In a study from California, Petreas et al. (68) measured only BDE-47 concentrations in adipose tissue samples from women (n=32) collected between 1996 and 1998. BDE-47 was detected in all samples with a median concentration of 16.5 ng/g lipid wt (range, 5.2 – 196 ng/g lipid wt). The limit of detection reported for BDE-47 (LOD, < 0.5 ng/g lipid wt) in adipose fat was < 20 times lower than the limit of detection reported for the same congener in serum (LOD, 10 ng/g lipid wt). PBDE concentrations from a set of 23 samples reported by She et al. (23) showed a negative correlation with age (Spearman, R = -0.413, P 183 > 99 > 100. These congeners collectively constituted 96% of the ∑PBDE concentrations. In Tarragona, BDE-183 as a marker of octa-BDE mixture, was not detected. Tan et al. (74) investigated BDE concentrations in 88 maternal adipose tissues from Singapore. BDE-153 was the most common congener detected but PBDE-47 was the most abundant congener in the samples. BDE-47 accounted for 37% with a median of 1.84 ng/g lipid wt, followed by BDE-153, accounting for 28%, with a median of 1.39 ng/g lipid wt. Choi et al. (75) investigated the levels of PBDEs in women of ages 40-50 years from Tokyo, Japan. Adipose tissue samples were collected in 1970 and in 2000. The median concentration in samples from 2000 (1.3 ng/g lipid wt.) was more than 40 times greater than the median concentration in samples from 1970 (0.03 ng/g lipid wt). BDE-47 was the predominant congener in the samples accounting for > 56% of the total PBDE concentration in 1970 and 35.6 % in 2000. Changes in the PBDE product usage during the past 30 years (1970-2000) were reflected in the variation in PBDE profiles in tissues. Reported concentrations of PBDEs in samples of adipose tissue (23, 68), serum (76), and milk (77) were obtained from archived specimen banks in the U.S. and demographic information was limited for those samples. The rising levels of PBDEs in the world and the higher levels detected in the U.S. highlighted the importance of conducting systematic biomonitoring studies to assess the risks associated with such exposures. Studies that measure PBDE concentrations along with several biological variables can help in understanding the factors that influence the accumulation of PBDEs in individuals. Breast milk and adipose tissue samples collected, along with several demographic variables such as gender, age, race, and occupation, were used to investigate PBDE concentrations (25, 78, 79).


32


Table 3. Median concentrations of PBDEs (ng/g lipid weight) in human samples from selected countries, published in peer-reviewed journals. Geometric mean (GM), CA = California; IL =Illinois; IN = Indiana; New York = NY; MA= Massachusetts; Meryland = MD; MS= Mississippi; Montana = MO, Oregon=OR, Tennessee = TN; TX = Texas; Washington =WA. British Columbia, Canada = BC Country / Region

Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

Australian Melbourne

milk

2003-2003

pool

47, 99, 100, 154, 183, 196

9 - 12.4

11.2

(103)

Sydney

milk

2004-2003

pool

47, 99, 100, 154, 183, 196

8.5 - 11

9.75

(103)

adipose tissues

2000

20

28, 47, 99, 100, 153

2.23 - 11.7

3.9

(70)

adipose tissues

2001-2003

53

28, 47, 99, 100,153, 154, 183

1.23 - 57.2

5.32

(71)

adipose tissues

2004-2005

25

17, 28, 47, 71, 85, 99, 100, 138, 153, 154, 183

0.19132

1.51

(110)

milk

1992

10

28, 47, 99, 100,153, 154, 183

0.79 - 28.5

3.14

(111)

Belgium Antwerp

Brazil Porto Alegre Canada Ontario/Quebec China


33


Country / Region

Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

Guangzhou

cord serum

2005

21

28, 47, 99, 100,153, 154, 183

1.5 - 12

3.9

(84)

Guangzhou

milk

2005

27

28, 47, 99, 100,153, 154, 183

1.7 - 7.2

3.5

(84)

Guangzhou

serum

2005

21

28, 47, 99, 100,153, 154, 183

1.6 - 17

4.4

(84)

Guangzhou

serum

2005

15

28, 47, 99, 100,153, 154, 183, 196,197, 203,206, 207, 208, 209

6.2 - 578

35.1

(88)

Guangzhou

serum

2005

20

28, 47, 99, 100,153, 154, 183,197, 207, 208, 209

1.3 - 95.6

10.1

(88)

milk

2003

103

28, 47,49, 66, 99, 100,153, 154, 183

0.16 - 13.3

2.2

(100)

Copenhagen

milk

1997 - 2001

36

28, 47, 66,85, 99, 100,153

1.1 – 9.1

3.3

(102)

Copenhagen

placenta

1998 - 2001

129

28, 47, 99, , 100,153, 154, 183

0.6-3.3

1.3

(102)

Tórshavn

milk

1999

9

47, 99, 100,153, 209

4.7 - 13

5.8

(101)

Tórshavn

serum

1994 -1995

57

47, 99, 100,153, 209

0.4 – 50.1

3.9

(81)

Czech Republic Olomouc Denmark

Faroe Island

Continued on next page.


34


Table 3. (Continued). Median concentrations of PBDEs (ng/g lipid weight) in human samples from selected countries, published in peer-reviewed journals. Geometric mean (GM), CA = California; IL =Illinois; IN = Indiana; New York = NY; MA= Massachusetts; Meryland = MD; MS= Mississippi; Montana = MO, Oregon=OR, Tennessee = TN; TX = Texas; Washington =WA. British Columbia, Canada = BC Country / Region

Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

Finland Turku

milk

1997 - 2001

32

28, 47, 66, 99, 100,153, 154, 183

1.04 - 29.5

3.1

(102)

Turku

placenta

1998 - 2001

56

28, 47, 66,99, , 100,153

0.35 9.9

1.2

(102)

Venice

milk

2000 - 2001

pool

17, 28, 47,66, 85, 99, 100,153, 154, 183

1.6 - 2.8

2.5

(96)

Rome

milk

1998 - 2000

pool

17, 28, 47,66, 85, 99,100,153, 154, 183

4.1

(96)

Tokyo

adipose tissues

1970

10

28, 47, 99, 100

0.007 – 0.08

0.029

(28)

Tokyo

adipose tissues

2000

10

28, 47, 99, 100, 153, 154, 183

0.47 - 2.8

1.29

(28)

Kyoto

milk

2004

30

28, 47, 99, 153, 154,

1.39 (GM)

(106)

Shimane

milk

2004

20

28, 47, 99, 100, 153, 154, 183

0.83 (GM)

(106)

Italy

Japan


Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

Hokkaido

milk

2005

20

15, 28, 47, 99, 100,153, 154, 183, 196,197,206, 207, 209

1.02 - 4.55

2.23 (GM)

(83)

Miyagi

milk

2005

40

15, 28, 47, 99, 100,153, 154, 183, 196, 197, 206, 207, 209

0.49 - 3.41

1.42 (GM

(83)

Gifu

milk

2005

20

15, 28, 47, 99, 100,153, 154, 183, 196,197,206, 207, 209

0.66 - 2.38

1.45 (GM)

(83)

Hyogo

milk

2005

9

15, 28, 47, 99, 100,153, 154, 183, 196,206, 207, 209

0.49 - 4.55

1.3 (GM)

(83)

Kanagawa

milk

1999

10

28,37, 47, 66,99, 100,153, 154, 183

0.56 - 2.91

1.47

(83)

Hokkaido

serum

2005

20

15, 28, 47, 99,100, 154, 183, 196, 197, 203, 207,209

1.04 - 5.43

2.75 (GM)

(83)

Miyagi

serum

2005

40

15, 28, 47, 99,100, 154, 183, 196, 197, 203, 206,207,209

1.33 - 21.2

3.64 (GM)

(83)

Gifu

serum

2005

20

15, 28, 47, 99,100, 154, 183, 196, 197, 203, 207,209

0.74 - 4.5

2.06 (GM)

(83)

35


Country / Region



36



Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

0.76 - 5.38

2.52 (GM)

(83)

serum

2005

9

15, 28, 47, 99,100, 154, 183, 196, 203, 206, 207,209

Ciudad Juarez

serum

2006

43

47, 99,100, 153, 154,209

4.8 (GM)

(112)

San Luis Potosi

serum

2006

16

47, 99,100, 153, 154,209

7.3 (GM)

(112)

Milpillas

serum

2006

52

47, 99,100, 153, 154,209

8.6 (GM)

(112)

El refugio

serum

2006

15

47, 99,100, 153, 154,209

15.7 (GM)

(112)

San Juan Tilapa

serum

2006

20

47, 99,100, 153, 154,209

3.7 (GM)

(112)

Chihuahua

serum

2006

27

47, 99,100, 153, 154,209

2.7 (GM)

(112)

milk

2006

22

47, 99, 100, 154

2

(97)

Murmansk

milk

2000

14

47, 99,100, 154,183

1.09

(99)

Arkhangelsk

milk

2000

23

28, 47, 99,154, 183,209

1.13

(99)

Hyogo Mexico

Poland Wielkopolska

0.8 - 8.4

Russia


Country / Region

Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

37


Sweden Stockholm

adipose tissues

1994

5

28, 47, 85, 99, 100, 154, 183

3.8 - 7.7

5.2

(69)

Stockholm

plasma

2000 - 2001

15

28, 47, 66, 99, 100, 154, 183, 196

6.53 - 57.9

2.07

(80)

Stockholm

cord plasma

2000 - 2001

15

28, 47, 66, 99, 100, 154, 196

1.1 - 9.42

1.69

(80)

Stockholm

liver

1994

5

28, 47, 85, 99,100, 154,183

4.5 - 18.4

5.8

(69)

Stockholm

milk

1972

pool

47, 154

0.07

Stockholm

milk

1976

pool

28, 47, 66, 99, 100, 154,183

0.35

Stockholm

milk

1980

pool

28, 47, 99, 100, 154,183

0.48

Stockholm

milk

1984/1985

pool

28, 47, 99, 100, 154,183

0.73

Stockholm

milk

1990

pool

28, 47, 66, 99, 100, 154,183

1.21

Stockholm

milk

1994

pool

28, 47, 66, 99, 100, 154,183

2.17

Stockholm

milk

1996

pool

28, 47, 66, 85, 99, 100, 154,183

3.11 Continued on next page.


38



Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

Stockholm

milk

1997

pool

28, 47, 66, 85, 99, 100, 154,183

Uppsala

milk

1996-1999

93

47, 99, 100, 154,183

0.91 - 28.2

3.15

(95)

Stockholm

milk

2000 - 2001

15

28, 47, 66, 85, 99, 100, 154,183, 196

0.56 - 7.72

2.14

(80)

adipose tissues

2006

88

47, 99,100, 154,183, 196

4.93

(74)

Tarragona

adipose tissues

1997

13

47, 99, 100, 154

1.02 -11.9

3.1

(72)

Granada

adipose tissues

2003

20

28, 47, 66, 85, 99, 100,154, 183, 196, 197, 203, 209

1.4 - 10.6

2.94

(73)

Madrid

serum

2003 -2004

61

47, 66, 85, 99, 100,154, 183, 196, 203, 207

9.6

(108)

Madrid

cord serum

2005 -2004

44

47, 66, 99, 100, 154, 183, 196, 197, 203, 207

14.9

(108)

4.02

Singapore Singapore Spain


39


Country / Region

Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

Madrid

milk

2006 -2004

22

28, 47, 85, 99, 100, 154, 183, 196, 197, 207

5.6

(108)

Madrid

placenta

2007 -2004

30

28, 47, 66, 99, 100, 154, 183, 196, 197, 207

1.8

(108)

milk

1998

103

28, 47, 99,100, 154, 196

3.34

(98)

milk

2003

37

47, 99

1.4 - 0.4

0.23

(113)

London

milk

2001-2003

27

28, 47, 99, 100, 153,154

3.1 - 6.9

7.8

(104)

Lancaster

milk

2001-2003

27

28, 47, 99, 100, 153,154

0.3-34

4.6

(104)

CA

adipose tissues

1996 - 1999

23

47, 99, 153, 154

17.2 - 462

41.4

(23)

NY

adipose tissues

2003-2004

52

28, 30, 47, 85, 99, 100, 153, 154

17 - 9630

75

(24)

IN

cord serum

2001

12

47, 99, 100, 153, 154

14 - 460

39

(107)

MD

cord serum

2004 - 2005

297

28, 47, 85, 99, 100, 153, 154,183

26.9

(114)

IL

serum

1988

12

47, 99, 100, 153, 154

7.06

(76)

The Netherlands

Turkey Kahramanmaras United Kindom

United States

0.5 - 134



Country / Region

Sample

n

Year collection

PBDE congeners

Range

∑PBDEs

References

TN

serum

1985 -1989

pool

47, 100, 153

4.6 - 74

9.6

(115)

TN

serum

1990 -1994

pool

47, 85, 99

7.5 - 86

48

(115)

TN, WA

serum

1995 -1999

pool

47, 85, 99, 100, 153, 154

42 - 120

71

(115)

TN, WA

serum

2000 -2002

pool

47, 85, 99, 100, 153, 154

47 - 160

61

(115)

MS

whole blood

2003

29

17, 28, 47, 66, 85, 99, 100, 138, 153, 154, 183

4.7 - 362

30.8

(17)

NY

whole blood

2003

10

28, 47, 99, 100, 138, 153, 154, 183

4.6 - 135

25

(116)

MO, OR,WA,BC

milk

2003

40

28, 32, 47, 66, 85, 99, 100, 153, 154, 183

6.34 - 321

50.4

(92)

TX

milk

2001 - 2004

47

17, 28, 47, 66, 85, 99, 100, 138, 153, 154, 183

6.2 - 418

34

(77)

MA

milk

2004 - 2005

46

28, 47, 66, 85, 99, 100, 138, 153, 154, 183

4.3 - 264

30.2

(78)

MA

milk

2005

38

28, 47, 66, 77, 85, 99, 100, 118, 138, 153, 154, 183, 203, 209

0.06 -1910

19.8

(49)

40


Table 3. (Continued). Median concentrations of PBDEs (ng/g lipid weight) in human samples from selected countries, published in peer-reviewed journals. Geometric mean (GM), CA = California; IL =Illinois; IN = Indiana; New York = NY; MA= Massachusetts; Meryland = MD; MS= Mississippi; Montana = MO, Oregon=OR, Tennessee = TN; TX = Texas; Washington =WA. British Columbia, Canada = BC



Blood Blood is the most common type of specimen used in human biomonitoring studies for PBDEs and chlorinated contaminants. Blood samples have been used as whole blood, serum, or plasma. Plasma is obtained by centrifugation of the whole blood sample with an appropriate anti-coagulant such as EDTA or heparin, while serum is produced from whole blood by centrifugation without any added anticoagulant. There were identified seversal types of blood samples used in various studies. Although blood samples are relatively easy to collect and the levels of contaminants in blood represent the most recent exposures, contaminant analysis in this matrix has some limitations. The most significant limitation is the need for a large volume of sample (10 – 20 ml) to quantify PCBs and PBDEs due to the low lipid content present in this matrix (1 - 3%). Nevertheless, recent state of the art analytical methods based on solid phase extraction (SPE) and high resolution mass spectrometry (HRMS) require less than 2 ml of blood. Other limitations of monitoring using a blood matrix include the need for expensive GC coupled to HRMS and the low limits of detection when low volumes of samples are used. Concentrations of PBDEs (tri – hexa-BDEs) in serum samples from the U.S. and Canada were compared with those from European countries (80–82), Japan (83), and China (84–87). Concentrations of PBDEs were one to two orders of magnitude higher in North American samples than in European or Asian samples. In samples from the U.S., BDE-17, 28, 31, 47, 66, 72, 77, 138, 153, 154, 183, and 209 were detected. BDE-47, 153, and 99 were the predominant congeners, accounting for 43 - 64%, 3.3 – 14%, and 0.5 – 6.7%, respectively, of the total PBDE concentrations. Only a few studies have reported concentrations of BDE-209 in blood. However, low median concentrations of BDE-209, ranging from < LOD to 1.5 ng/g lipid wt, in the U.S.,

Human Exposure to Brominated Flame Retardants - ACS Publications

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