1 Introduction and ObjectivesPatterns and Trends in Perfluoroalkyl Acids in Bald Eagle Nestlings in the Upper Midwest William T. Route1, Robin E. Russell2, Andrew B. Lindstrom3, Mark J. Strynar3, and Rebecca L. Key1 1 = National Park Service, Great Lakes Inventory and Monitoring Network, Ashland, WI; 2 = U.S. Geological Survey, National Wildlife Health Center, Madison, WI; 3 = National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC Introduction and Objectives Perfluoroalkyl acids (PFAAs) are under scrutiny due to their global use, persistence, bioaccumulative properties, and growing evidence of toxicity. Species that feed high on the trophic food web can serve as sentinels for chemical contamination. In particular, bald eagle nestlings are fed from a relatively small territory so that concentrations in their blood provide a measure of local contamination. Our objectives were to evaluate the spatial and temporal patterns of PFAAs in bald eagle nestlings at national parks in the upper Midwest and to examine routes of exposure to wildlife and humans. Results from the first six years of this monitoring have been reported (Route et al. 2014) and data collection will continue through at least 2015. We report on the sum of 16 PFAAs as well as three individual analytes that are of particular interest – PFOS and PFOA due to their high use and toxicity, and PFDS due to a paucity of data in the literature: ƩPFAA = the sum of all 16 PFAAs measured, PFOS = perfluorooctane sulfonate, PFOA = perfluorooctanoic acid, and PFDS = perfluorodecane sulfonate. Results From 2006 through 2011 we sampled and analyzed blood plasma from 261 nestling bald eagles. We found concentrations of ƩPFAAs in a single individual as high as 7370 ng/mL, the highest level we are aware of. Geometric means among study areas ranged from 163 ng/mL on the remote U-SACN to 941 ng/mL at Pools 3 & 4 on the Mississippi River (Fig. 6). Spatial patterns in concentrations of the most prevalent PFAA analytes, PFOS and PFDS (Figs. 7 and 8), were similar to the ƩPFAA and made up 67% and 23% of the total PFAA burden, respectively. These analytes were particularly high in nestlings near the 3M™ Cottage Grove facility (callout A in figures 6-9) and downstream from municipal wastewater treatment plants for Minneapolis-St Paul, MN (callout B) and Taylors Falls, MN and St. Croix Falls, WI (callout C). Note: the range of concentrations within each bin in the figures were generated using the Natural Breaks feature in Arc GIS. Figure 1. Locations of 6 study areas including 3 national parks where bald eagles are being used to monitor concentrations of perfluoroalkyl acids. Methods Bald eagle nestlings were hand captured in the nest when four to nine weeks old and brought to the ground (Figs. 2 and 3). We took <11mL of blood and measured, weighed, and banded nestlings before releasing them unharmed (Figs. 4 and 5). Blood samples were centrifuged and the plasma frozen for transport to three independent laboratories. PFAA levels were measured by high performance liquid chromatography/ tandem mass spectrometry. We used regression analysis in a Bayesian framework to combine results from all three laboratories and evaluate spatial and temporal trends. Study Areas We sampled bald eagle nestlings at Apostle Islands National Lakeshore (APIS), the upper and lower St Croix National Scenic Riverway (U-SACN, L-SACN), the Mississippi National River and Recreation Area (MISS), and two areas adjacent to these National Park Service units: the Lake Superior south shore (LSSS), and Mississippi River pools 3 & 4 (Fig. 1). Figure 6. Geometric mean concentrations of ƩPFAAs in bald eagle nestling plasma in 6 study areas, Figure 7. Geometric mean concentrations of PFOS in bald eagle nestling plasma, Figure 8. Geometric mean concentrations of PFDS in bald eagle nestling plasma, Figure 9. Spatial distribution of PFOA, in bald eagle plasma at 6 study areas. The analyte PFOA was distributed differently than PFOS and PFDS. We found PFOA at low levels overall (PFOS was up to 980-fold higher), but it was consistently highest in nestlings from APIS on Lake Superior (Fig. 9). Differences are likely due to the sources and chemical properties of these related contaminants. We argue that higher levels of PFOS and PFDS at L-SACN, MISS, and Pools 3 & 4 study areas (Figs. 7 and 8) are associated with point-sources in this highly urban and industrial region. PFOS was produced by the 3M™ Corporation (A) since the 1950s along the Mississippi River and other PFAA analytes were likely by-products. PFOS readily binds to sediments and is known to rapidly bioaccumulate in food webs. By contrast, PFOA is more water-soluble, bioaccumulates less, and has a longer half-life in water than other PFOA. Moreover, we speculate that PFOA was higher in nestlings on Lake Superior (APIS) partly due to the lake’s large surface area and many tributaries, which collect this contaminant from regional and global sources. The waters of the remote U-SACN study area, where the human population is relatively spares, had the lowest levels of all PFAA analytes (compare Figs ). Our results show strong evidence of decline in levels of ƩPFAA and five analytes including PFOA and PFDS (P >90%); moderate evidence of decline in two analytes including PFOS (P >80% to <90%); no evidence of change in three analytes (P >30% to <70%); and evidence of increase in two analytes (P for decline = 0). The overall declines we observed in PFAAs were concomitant with reduced use and manufacture by industry beginning in about 2002 (Fig. 10). For example, the 3M™ Corporation and the DuPont Corporation have met or exceeded their goals of zero PFOS release by Nevertheless, these chemicals will continue to enter the environment for many years due to leaching from landfills and because of the slow breakdown of the many products that contain them. Summary Over a six-year monitoring period we documented extensive contamination of PFAAs in aquatic ecosystems of the upper Midwest using bald eagle nestlings as bio-sentinels. We modeled results using a Bayesian statistical framework that included measurements from three independent laboratories across six study areas. Our results support other studies linking PFAA levels to effluent from municipal wastewater treatment plants and industrial waste disposal. We found that PFOS and PFDS were the primary analytes accumulating in bald eagle nestlings in these study areas. By contrast, PFOA was found at low levels and was distributed differently. PFOA was highest in nestlings found on Lake Superior, likely due to differences in source and chemical properties. All PFAAs were lowest on the remote upper St. Croix Riverway. Most analytes were found to be declining in concert with reduction in use of these chemicals in manufacturing. Acknowledgments Major funding for this program was provided by the U. S. National Park Service’s Vital Signs Monitoring Program with additional funding from the Environmental Protection Agency’s Great Lakes Restoration Initiative, the Minnesota Pollution Control Agency, and the Donald Weesner Foundation. Figure 3. Bald eagle nestlings, about 7 to 8 weeks-old, in nest overlooking the St. Croix River. Photo by Jim Campbell-Spickler. Figure 2. Climber/biologist Jim Campbell-Spickler, Eco-Ascension Research and Consulting, begins the climb. Photo by Eli Nichols. Figure 10. Trends in PFOS (top) and PFOA (bottom) concentrations (mean +/- SE) in bald eagle nestling plasma, Publications Route, W.T., R.E. Russell, A.B. Lindstrom, M.J. Strynar, and R.L. Key Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the upper Midwestern United States. Environmental Science and Technology (48): Route, B., P. R. Rasmussen, R. Key, M. Meyer, and M. Martell Spatial patterns of persistent contaminants in bald eagle nestlings at three national parks in the upper Midwest: National Park Service, Natural Resource Technical Report NPS/GLKN/NRTR-2011/431. Available on line at Figure 5. Climber/biologist Jim Campbell-Spickler discusses an eaglet’s role in monitoring contaminants. Figure 4. National Park Service ecologist Bill Route and collaborator Mark Martell, Audubon Minnesota, draw a blood sample from a 6 to 7 week-old nestling. Photo by Eli Nichols.