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Patterns and Trends in Brominated Flame Retardants in Bald Eagle Nestlings from the Upper Midwestern United States William Todd Route, Cheryl R. Dykstra, Paul W Rasmussen, Rebecca L Key, Michael W Meyer, and John Mathew Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/es501859a • Publication Date (Web): 01 Oct 2014 Downloaded from http://pubs.acs.org on October 4, 2014
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Patterns and Trends in Brominated Flame Retardants in Bald Eagle Nestlings from the Upper Midwestern United States
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plasma of 284 bald eagle nestlings sampled between 1995 and 2011 at six study areas in the
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upper Midwestern United States. Geometric mean concentrations of total PBDEs (Ʃ of nine
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congeners) ranged from 1.78 ng/mL in the upper St. Croix River watershed to 12.0 ng/mL on the
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Mississippi River. Lake Superior nestlings fell between these two extremes. Between 2006 and
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2011 trends differed among study areas with three declining, two remaining stable, and one
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increasing. Variation in ƩPBDE trends among study areas was linked to trends in individual
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congeners. The lower brominated PBDEs (BDE-47, 99, and 100) declined 4-10% while the
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higher brominated congeners (BDE-153 and 154) increased by about 7.0% annually from 2006
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to 2011. This increase was greatest in nestlings from the St. Croix River and below its
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confluence with the Mississippi River. Region-wide, our data suggests ƩPBDEs increased in
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bald eagle nestlings from 1995 through the mid-2000s and then declined by 5.5% annually from
William T. Route*, U. S. National Park Service, Great Lakes Inventory and Monitoring Network, Ashland, WI 54806, United States Cheryl R. Dykstra, Raptor Environmental, 7280 Susan Springs Drive, West Chester, OH 45069, United States Paul W. Rasmussen, Wisconsin Department of Natural Resources, Monona, Wisconsin 53716, United States Rebecca L. Key, U. S. National Park Service, Great Lakes Inventory and Monitoring Network, Ashland, WI 54806, United States Michael W. Meyer, Wisconsin Department of Natural Resources, Rhinelander, Wisconsin 54501, United States John Mathew, Wisconsin State Laboratory of Hygiene, 2601 Agricultural Drive, Madison, WI 53718, United States
Abstract. We report on patterns and trends in polybrominated diphenyl ethers (PBDEs) in
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2006 to 2011. These regional trends are consistent with the removal of penta- and octa-PBDEs
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from the global market.
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TOC Photo.
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Introduction
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Polybrominated diphenyl ethers (PBDEs) have been used since the 1970s as flame retardants in
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plastics, electronic circuitry, textiles, foams, and many other commercial products. Although
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PBDEs have reportedly saved lives from accidental fire,1 there is concern over their persistence,
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bioaccumulation, and toxicity.1-6 PBDEs have become ubiquitous in air, sediments, wildlife, and
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humans around the world.4, 7-9 Moreover, findings from studies on humans and laboratory
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animals show they can transfer from mother to infant,10 interfere with immune,2 and thyroid
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function6 and alter human infant behavior.11
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PBDEs are commercially available in three formulations: penta-, octa-, and deca-BDEs,
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which are themselves mixtures of from four to 12 congeners.12 Our study focuses on congeners
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in the penta- formulation which are particularly persistent and therefore of concern as
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environmental pollutants.13, 14 Several governments have now banned or restricted use of penta2 ACS Paragon Plus Environment
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and octa-BDEs: the European Union banned manufacture and use in 20041 and production was
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halted voluntarily in the United States in 2004 followed by restrictions on use and import in
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2005.15 Before these restrictions took place, about 95% of the worldwide production of penta-
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BDE was consumed in North America.16 In the Great Lakes region, it has been estimated that the
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cumulative inventory of penta- and octa-BDEs in manufactured products peaked at 12,000
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tonnes by 2004 and that most of these products will degrade and enter the waste stream by
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2020.17
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Numerous studies have documented the global increase of PBDE concentrations in biota
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with more recent work showing some congeners have plateaued or started to decline.18 For
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example, on the Great Lakes, penta- and octa-BDE congeners increased in rainbow smelt
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(Osmerus mordax) and lake trout (Salvelinus namaycush) in the early 1980s through the mid-
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1990s when they began to decline19 and these same PBDE congeners plateaued in herring gull
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(Larus argentatus) eggs by 2000.20 In a summary of studies across North America, Asia, and
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Europe it has been shown that PBDE concentrations increased dramatically in aquatic birds and
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marine mammals from the early 1970s until the late 1990s and early 2000s and then stabilized or
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declined.21
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Bald eagles (Haliaeetus leucocephalus) are effective indicators of environmental
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contamination because they are high on the aquatic food web and act as integrators of human-
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made contaminants that enter aquatic systems through direct discharge, aerial deposition, and
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runoff.22-24 In particular, the nestlings can reveal local contamination because they are fed from
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within a territory of 4 to 5 km2 in size.25, 26 There have been several efforts to monitor
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environmental contaminants in bald eagle nestlings on the Great Lakes27-30 but we are aware of
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only two that have reported on concentrations of PBDEs. Dykstra et al.28 reported for the first
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time on PBDE levels in plasma from five nestlings on the Wisconsin shore of Lake Superior in
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2000 and 2001. They found a geometric mean concentration of 7.9 ng/mL (95% CI = 6.0-10.4).
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Venier et al.31 reported ƩPBDE levels in 2005 to range from 0.35-29.3 ng/mL (mean 5.7 ng/mL;
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non-detections omitted) in nestlings from 15 sites across Lakes Michigan, Huron, and Superior.
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To better understand the patterns and trends in environmental contaminants, including
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PBDEs, the U.S. National Park Service (NPS) began monitoring contaminants in bald eagle
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nestlings in national parks of the upper Midwest in 2006. 32 This program was designed to be
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consistent with previous work by the Wisconsin Department of Natural Resources (WDNR) who
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collected blood samples from bald eagle nestlings in some of the same areas from the late 1980s
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until 2002.28 Our objectives in this study are to report on archived samples from WDNRs earlier
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work and the contemporary samples from NPS to illustrate spatial patterns and temporal trends
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in PBDE concentrations and to examine their relationship to human land use in the region.
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Materials and Methods Study Areas. Blood samples were collected from five- to nine-week-old bald eagle
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nestlings at six study areas in the upper Midwestern United States (Figure 1). From 2006
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through 2011 we sampled at four core study areas: the Apostle Islands National Lakeshore
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(APIS), the upper St. Croix National Scenic Riverway (U-SACN), the lower St. Croix National
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Scenic Riverway (L-SACN), and the Mississippi National River and Recreation Area (MISS).
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The SACN was subdivided because of differences in hydrology and land-use.33, 34 When funding
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allowed we also sampled along Wisconsin’s Lake Superior South Shore (LSSS) and downstream
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from MISS in Pools 3 and 4 of the Mississippi River (Pools 3&4). Finally, we analyzed samples
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archived by WDNR that were collected from nestlings at LSSS and APIS between 1995 and
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2002.
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Figure 1. Location of six study areas in the upper Midwestern United States where bald eagle nestlings were sampled for polybrominated diphenyl ethers, 1995-2011.
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Sample Collection. Procedures for collecting archived (n= 17) and contemporary (n=
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267) samples were similar and described previously.28, 32, 33 Briefly, we used aircraft to map all
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occupied bald eagle nests in each study area. From mid-May to late June each year, we climbed
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to nests, hand-captured the nestlings, and brought them to the ground for sampling. Nests were
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excluded if the tree was unsafe to climb, if the nestling(s) were too old or young to sample, or if
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access through private property was denied.
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Each nestling was weighed (unadjusted for crop content), measured, and examined for
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abnormalities. Nestlings were aged using length of the eighth primary35 and sex was determined
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by physical measurements (1995-2002) or by PCR-based genetic analysis36 (2006-2011). We
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collected
