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S. Gallo 1 , D. Soucek 1 , J. Levengood 1 , W. Hill 1

Study tracks contaminant transfer from sediments to aquatic insects to tree swallow eggs in Illinois. Findings on contaminants, growth, and transfer pathways are explored.

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S. Gallo 1 , D. Soucek 1 , J. Levengood 1 , W. Hill 1

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  1. Risks to Insectivorous Birds in the Calumet Regionfrom Transfer of Contaminants from Sediments toEmergent Aquatic Insects S. Gallo1, D. Soucek1, J. Levengood1, W. Hill1 and G. Bordson21Illinois Natural History Survey, Champaign IL; 2Illinois Sustainable Technology Center, Champaign IL;

  2. Funding: The Illinois Waste Management and Research Center, WMRC (ISTC) Department of Natural Resources and Environmental Sciences, UIUC Center for Ecological Entomology, INHS

  3. Overall Objectives • Observational study to quantify contaminant loads in sediments, aquatic insects and tree swallow eggs and nestlings in Calumet, IL. • Attempt to understand the movement of contaminants between aquatic and terrestrial ecosystems • Use stable isotope analysis to try to determine the source of the contaminants

  4. Contaminant Transfer Between Ecosystems: Tachycineta bicolor Contaminants in sediments or water

  5. Photo: John Marlin

  6. Sites • 30 Nest boxes at each site • 2 Contaminated Sites • Big Marsh • Indian Ridge • 1 “Reference” Site • Powderhorn Lake • No record of contaminants Big Marsh Indian Ridge Powderhorn Lake N

  7. Procedures Collected in 2004 & 2005: Birds: Tree Swallows (Tachycineta bicolor) • 2 eggs from each of 10 nests • 1 14-day-old nestling from same 10 nests Insects: • Emergence traps • Benthic samples • Bolus material (analyzed for contaminants in 2005 only) Sediment grabs

  8. Analyses 12 priority elements measured: Ag, As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Zn. Approximately 60 different Organics measured: PCBs, PBDEs, DDTs and Other organo-chlorine pesticides

  9. Nesting Ecology

  10. -No differences among sites in # nestlings /nest, nest success, hatch success, fledge success. Nest success ranged from 69 to 83%. -Mass of nestlings at BM and IRM were significantly lower than at PL. Related to greater # eggs/nest (BM > PL in 2004).

  11. Site Vegetation • Reference Site: approximately 2x more canopy cover * ** Orthogonal contrasts comparing to Reference: ** <0.01, *<0.05

  12. Diet

  13. Total mass of aquatic or terrestrial arthropods represented in the 2005 boluses. N= 61, 26, 25 for Big Marsh, Indian Ridge and Powderhorn, respectively.

  14. Contaminants

  15. Mercury accumulation *** * * mg/kg total Hg dry wt Growth dilution with no addition Orthogonal contrasts comparing to Reference: *** <0.0001, *<0.05

  16. Synthesizing Ecology and Contaminant Data:Nest Initiation and Egg Hg levels

  17. Contaminant Transfer Pathways: Local and Migratory Local Migratory -Eggs form ~6 days before laying -Hg half-life in other birds is 40 to 84 days -swallows arrive 14-28 days before laying -at least some Hg in eggs must be from non-local sources http://www.birdnature.com/flyways.html

  18. 4,4’-DDD in eggs and nestlings

  19. 4,4’-DDD in eggs and nestlings

  20. PBDEs in eggs and nestlings

  21. PBDEs in eggs and nestlings

  22. PBDEs in eggs

  23. PBDEs in nestlings

  24. Contaminant sources

  25. Stable Isotopes • Measure of light to heavy C and N isotope ratios • C13/C12 ratio in organisms changes very little w/ increasing trophic level and can indicate percentage of sources/prey items that are being consumed • N15/N14 ratio can indicate trophic level. N15 increases with trophic level because consumers excrete N14 at a faster rate • Both can provide insight into long term food resource use rather than short term use (i.e. gut content analyses) • Expressed as 15N and13C -- ratio of isotopes in sample relative to ratio in standards (air for N, and Pee Dee Belamite for C).

  26. Stable Isotopes • Measure of light to heavy C and N isotope ratios • C13/C12 ratio in organisms changes very little w/ increasing trophic level and can indicate percentage of sources/prey items that are being consumed • N15/N14 ratio can indicate trophic level. N15 increases with trophic level because consumers excrete N14 at a faster rate • Both can provide insight into long term food resource use rather than short term use (i.e. gut content analyses) • Expressed as 15N and13C -- ratio of isotopes in sample relative to ratio in standards (air for N, and Pee Dee Belamite for C).

  27. Stable Isotope profiles of bolus insects Big Marsh Aquatic Terrestrial 15N 13.65 14.60 13C -27.65 -25.77 Indian Ridge Aquatic Terrestrial 15N 20.46 8.64 13C -25.07 -25.72 Powderhorn Aquatic Terrestrial 15N 4.48 5.44 13C -26.06 -25.65

  28. Sources of contaminants

  29. Conclusions • Tree Swallows in Calumet are accumulating a variety of contaminants through their diet • Site differences exist • Contaminant may be acquired from terrestrial sources more so than aquatic sources • Tree swallows prefer to nest at BM and IRM, potentially risking greater exposure to contaminants

  30. Questions?

  31. PCBs in eggs and nestlings

  32. PCBs in eggs and nestlings

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