Final Report: Polybrominated Diphenyl Ethers (Flame Retardants) in Babies, Sediment Cores, and Fishes

EPA Grant Number: R830397
Title: Polybrominated Diphenyl Ethers (Flame Retardants) in Babies, Sediment Cores, and Fishes
Investigators: Hites, Ronald A.
Institution: Indiana University
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 2003 through December 31, 2004
Project Amount: $228,760
RFA: Futures Research in Natural Sciences (2001) RFA Text |  Recipients Lists
Research Category: Land and Waste Management , Ecological Indicators/Assessment/Restoration , Hazardous Waste/Remediation

Objective:

Polybrominated diphenyl ethers (PBDEs) are flame-retardants that are added to plastics, particularly those used in furniture and in consumer electronics. Their use is unregulated and their concentrations in the environment are increasing. PBDEs have been found in human blood, fat, and milk. Concentrations of PBDEs are increasing exponentially(with a doubling time of 5 years) in human milk in Sweden. It seems likely that children in the United States are receiving the same level of exposure before birth.

First, we measured the concentration of PBDEs in umbilical cord blood obtained from 50 newborn infants from the United States. This told us if the fetus was exposed to these compounds, the variability in exposure among individuals, and if the degree of exposure was increasing with time. Data were collected on birth weight and gestational age as indicators of the baby’s overall health. In addition, information was collected on the mother’s employment history (sources of exposure), physical parameters (body mass index), smoking habits, and health history.

Second, to determine trends of these compounds in the United States’ environment as a function of time, we studied lake sediment cores and fishes from around the Great Lakes to assess the long-term trends of these compounds in the environment. Sediment cores are widely used to determine the historical input of pollutants into the environment, and our laboratory has had considerable experience with this approach. Thus, we obtained cores from three of the Great Lakes. We segmented and dated the cores such that we could determine the historical trends of PBDE inputs to the environment.

We also used collections of fish (primarily lake trout) that have been collected from the Great Lakes and archived by the U.S. Geological Survey. These fish date back to 1980 and have been collected biennially ever since. By analyzing fish from this historical collection, we obtained retrospective information on the input of PBDEs into this ecosystem.

Summary/Accomplishments (Outputs/Outcomes):

PBDEs in Maternal and Fetal Blood Samples

Concentrations of PBDEs were determined in human fetal and maternal serum. Patients presenting in labor to Indiana University and Wishard Memorial County hospitals in Indianapolis, who were greater than 18 years of age, were recruited to participate. Twelve paired samples of maternal and cord blood were obtained and analyzed using gas chromatographic mass spectrometry. Six PBDE congeners were measured in maternal and fetal serum samples. The concentrations of total PBDE found in maternal sera ranged from 15 to 580 ng/g lipid, and the concentrations found in fetal samples ranged from 14 to 460 ng/g lipid. In accord with reports on other biological samples, the tetra-brominated congener, BDE-47, accounted for 53-64 percent of total PBDE in the serum. The concentrations of PBDE found in maternal and fetal serum samples were 4- to 10-fold the levels previously reported in European studies on adult blood. Our study shows that the human fetus may be exposed to relatively high levels of PBDEs. Further investigation is required to assess the toxic potential of these exposure levels.

Determination of PBDEs in Environmental Standard Reference Materials

The total concentrations of 15 polybrominated diphenyl ethers, BDE-17, 28, 47, 49, 66, 71, 85, 99, 100, 138, 153, 154, 183, 190, and 209, and a predominant polybrominated biphenyl congener, 2,2',4,4',5,5'-polybrominated biphenyl (BB-153), were determined in six natural matrix Standard Reference Materials (SRM) provided by the National Institute of Standards and Technology. The total PBDE concentrations (± one standard deviation) in SRM 1945 (whale blubber), SRM 1946 (fish tissue), SRM 1947 (fish tissue), and SRM 1974b (mussel tissue) were 126 ± 7, 79 ± 3, 134 ± 5, and 7.9 ± 0.2 ng/g wet wgt, respectively. The total PBDE concentrations were 54 ± 2 and 163 ± 4 ng/g dry wgt for SRM 2977 (mussel tissue) and SRM 2978 (mussel tissue), respectively. Among the three kinds of marine animals, mussel tissue had the lowest total concentration of PBDEs. These values can provide an informal reference or benchmark to laboratories who measure these compounds.

PBDEs in the Environment and in People: A Meta-Analysis of Concentrations

This review summarizes PBDE concentrations measured in several environmental media and analyzes these data in terms of relative concentrations, concentration trends, and congener profiles. In human blood, milk, and tissues, total PBDE levels have increased exponentially by a factor of approximately 100 during the last 30 years; this is a doubling time of approximately 5 years. The current PBDE concentrations in people from Europe are approximately 2 ng/g lipid, but the concentrations in people from the United States are much higher at approximately 35 ng/g lipid. Current PBDE concentrations in marine mammals from the Canadian Arctic are very low at approximately 5 ng/g lipid, but they have increased exponentially with a doubling time of approximately 7 years. Marine mammals from the rest of the world have current PBDE levels of approximately 1,000 ng/g lipid, and these concentrations also have increased exponentially with a doubling time of approximately 5 years. Some bird’s eggs from Sweden also are highly contaminated (at ~2,000 ng/g lipid) and show PBDE doubling times of approximately 6 years. Herring gull eggs from the Great Lakes region now have PBDE concentrations of approximately 7,000 ng/g lipid, and these levels have doubled approximately every 3 years. Fish from Europe have approximately 10 times lower PBDE concentrations than fish from North America. From these and other data, it is clear that the environment and people from North America are very much more contaminated with PBDEs compared to Europe and that these PBDE levels have doubled every 4-6 years.

Temporal Trends and Spatial Distributions of Brominated Flame Retardants in Archived Fishes From the Great Lakes

To explore the geographical distribution and temporal trends of PBDEs in the Great Lakes, lake trout from Lakes Superior, Michigan, Huron, and Ontario and walleye from Lake Erie, collected during the period of 1980-2000, were analyzed. The concentrations of 15 PBDE congeners and 1 polybrominated biphenyl (BB-153) were determined in each fish sample. Lake trout from Lakes Michigan and Ontario had the highest total PBDE concentrations during the years investigated. The total PBDE concentrations in fishes from the five Lakes increased exponentially with time, doubling every 3 to 4 years. The relative proportion of BDE-47, 99, and 100 compared to BDE-153 and 154 increased significantly as a function of time. Over the period of 1980 to 2000, the concentrations of BB-153, which was a component of a flame retardant banned in the 1970s, generally remained the same in these Great Lakes fishes, except for lake trout from Lake Huron, where the BB-153 concentrations have decreased significantly, but slowly.

Novel Flame Retardants, 1,2-Bis(2,4,6-tribromophenoxy)ethane and 2,3,4,5,6-Pentabromoethylbenzene, in United States’ Environmental Samples

Two brominated flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (TBE) and 2,3,4,5,6-pentabromoethylbenzene (PEB) were detected and identified in ambient air samples from various sites in the United States. The identifications were confirmed by comparing the gas chromatographic retention times and mass spectra of the compounds found in the environment with those of authentic materials. Generally, the TBE concentrations in air were comparable to those of tetra- through hexabrominated diphenyl ethers and often higher than those of decabromodiphenyl ether (BDE-209). The atmospheric TBE concentrations at locations in the southern United States were higher than those in the northern United States. TBE also was found in a sediment core from Lake Michigan; the concentrations of TBE increased with time, were lower than those of BDE-209, but were approximately 10 times higher than the sum of BDE-47, 99, and 100. The maximum PEB concentration in Chicago air was 550 pg/m3, which was 10 times higher than the concentration of total PBDEs in this sample. In general, the concentrations of PEB in air samples were low but detectable and were less than those of PBDEs. PEB was not found in the sediment core from Lake Michigan. These occurrences of relatively high concentrations of TBE and PEB in environmental samples may reflect the increasing usage of these compounds as flame retardants.

Brominated Flame Retardants in Sediment Cores From Lakes Michigan and Erie

The history of PBDEs and the major polybrominated biphenyl congener (BB-153) was studied in dated sediment cores taken from Lakes Michigan and Erie. The surficial concentration of total PBDE (65 ng/g dry weight) in Lake Michigan was about 1.6 times higher than that in Lake Erie (40 ng/g) and about 5 times higher than that in Lake Superior (~12 ng/g). The concentrations of total PBDEs in these sediments have increased rapidly, with doubling times of 5-10 years, reflecting the increasing market demand for these flame retardants over the last 30 years. BDE-209 was found to be the predominant congener in both sediment cores, making up approximately 95 percent of the total PBDE load. The inventories of total PBDEs to Lakes Michigan and Erie were both 40 ng/cm2, respectively. The total burdens of these compounds in the sediment of Lakes Michigan and Erie were 23 and 10 metric tons, respectively. We estimate that the total burden of these compounds in all of the Great Lakes is on the order of 100 tons. In both Lakes, BB-153 was found to increase rapidly during the 1970s and to peak around 1980.

Brominated Flame Retardants in the Atmosphere of the East-Central United States

Air samples were collected at five sites (urban, semi-urban, agricultural, and remote) from Lake Michigan through the U.S. Midwest to the Gulf of Mexico every 12 days during 2002-2003, using high volume samplers so that we could study the spatial trends of brominated flame retardants (PBDEs, hexabromocyclododecanes [HBCDs], and TBE). The mean total PBDE atmospheric concentration was 100 ± 35 pg/m3 at the Chicago site, which was three to six times higher than at the other sites. The total PBDE atmospheric concentrations at the Chicago site were significantly higher than previous measurements made in 1997-1999. Unlike these former measurements, BDE-209 is now relatively abundant. Lower BDEs (tri- through hexa-BDEs) were detected in both the particle and gas phases, and the partitioning of these compounds between phases was highly dependent on atmospheric temperature. Higher BDEs (hepta- through deca-BDEs) were mostly detected in the particle phase. Based on the congener distributions in the samples, the concentrations were divided into three groups: penta-BDE, octa-BDE, and deca-BDE. Penta-BDE was the most concentrated at the Chicago site and the least at the Louisiana site; octa-BDE concentrations were low at all the sites; deca-BDE was the most concentrated at the Chicago site and notably high at the Arkansas site. High concentrations of deca-BDE, HBCD, and TBE at the Arkansas site suggest that manufacturing areas in southern Arkansas could be source regions. Backward trajectories for air masses with high concentrations of deca-BDE coming to the Arkansas site suggest that deca-BDE bound to particles can move long distances through the atmosphere.

Identification of Brominated Carbazoles in Sediment Cores From Lake Michigan

During the analysis of brominated flame retardants in sediment cores taken from Lake Michigan, a group of unknown brominated compounds were observed. To identify their chemical structures, a variety of gas chromatographic mass spectrometric techniques were used. With the help of high resolution and positive chemical ionization mass spectrometry, the molecular formula of the most abundant congener was established to be C12H5Br4N. Based on the electron impact and electron capture negative ionization mass spectra, this chemical was suspected of being a tetrabromocarbazole. The structure was confirmed by comparing the mass spectra and gas chromatographic retention times of an authentic standard of 1,3,6,8-tetrabromocarbazole with those of the most abundant unknown. The other unknown compounds may be other bromocarbazole congeners. The time trend determined by measuring these compounds as a function of depth in the Lake Michigan sediment cores indicated that the concentration of 1,3,6,8-tetrabromocarbazole peaked around 1920-1935.


Journal Articles on this Report : 8 Displayed | Download in RIS Format

Other project views: All 8 publications 8 publications in selected types All 8 journal articles
Type Citation Project Document Sources
Journal Article Hites RA. Polybrominated diphenyl ethers in the environment and in people: A meta-analysis of concentrations. Environmental Science & Technology 2004;38(4):945-956. R830397 (2003)
R830397 (Final)
  • Abstract from PubMed
  • Other: ACS PDF
    Exit
  • Journal Article Hoh E, Hites RA. Brominated flame retardants in the atmosphere of the east-central United States. Environmental Science & Technology 2005;39(20):7794-7802. R830397 (Final)
    R830395 (Final)
  • Abstract from PubMed
  • Other: ACS PDF
    Exit
  • Journal Article Hoh E, Zhu LY, Hites RA. Novel flame retardants, 1.2-bis(2,4,6-tribromophenoxy)ethane and 2,3,4,5,6-pentabromoethylbenzene, in United States' environmental samples. Environmental Science & Technology 2005;39(8):2472-2477. R830397 (Final)
  • Abstract from PubMed
  • Other: ACS PDF
    Exit
  • Journal Article Mazdai A, Dodder NG, Abernathy MP, Hites RA, Bigsby RM. Polybrominated diphenyl ethers in maternal and fetal blood samples. Environmental Health Perspectives 2003;111(9):1249-1252. R830397 (2003)
    R830397 (Final)
  • Abstract from PubMed
  • Full-text: Environmental Health Perspectives Full Text
    Exit
  • Other: Environmental Health Perspectives PDF
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  • Journal Article Zhu LY, Hites RA. Determination of polybrominated diphenyl ethers in environmental standard reference materials. Analytical Chemistry 2003;75(23):6696-6700. R830397 (2003)
    R830397 (Final)
  • Abstract from PubMed
  • Journal Article Zhu LY, Hites RA. Temporal trends and spatial distributions of brominated flame retardants in archived fishes from the Great Lakes. Environmental Science & Technology 2004;38(10):2779-2784. R830397 (2003)
    R830397 (Final)
  • Abstract from PubMed
  • Journal Article Zhu LY, Hites RA. Brominated flame retardants in sediment cores from Lakes Michigan and Erie. Environmental Science & Technology 2005;39(10):3488-3494. R830397 (Final)
  • Abstract from PubMed
  • Full-text: ACS Full Text
    Exit
  • Other: ACS PDF
    Exit
  • Journal Article Zhu LY, Hites RA. Identification of brominated carbazoles in sediment cores from Lake Michigan. Environmental Science & Technology 2005;39(24):9446-9451. R830397 (Final)
  • Abstract from PubMed
  • Full-text: ACS Full Text
    Exit
  • Other: ACS PDF
    Exit
  • Supplemental Keywords:

    ambient air, sediments, fishes, flame retardants, chemistry, surveys, monitoring, Great Lakes, and east central United States,, RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, INTERNATIONAL COOPERATION, Geographic Area, Waste, Water, Contaminated Sediments, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Biochemistry, Physical Processes, Children's Health, Ecological Risk Assessment, Ecology and Ecosystems, Environmental Policy, Great Lakes, neonates, fish borne toxicant, chemical exposure, infants, blood samples, exposure, contaminated sediment, flame retardants, PBDE, children, environmental sampling, human exposure, exposure pathways, fish-borne toxicants, human health risk, polybrominated diphenal ethers

    Progress and Final Reports:

    Original Abstract
  • 2003 Progress Report