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Mercury PowerPoint Presentation

Mercury

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Mercury

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  1. Mercury • Toxic trace element • Occurs naturally • Anthropogenic sources • Methyl form of most concern

  2. Natural sources Hg0

  3. Anthropogenic Sources Hg0 Hgp Hg2+

  4. Mercury in the Environment • Inorganic Hg is now the predominant source of methylated mercury • Fossil fuel burning

  5. Chemical Pollution • Inorganic form and methyl form both toxic • Becomes methylated through natural transformations • Biomagnification and bioaccumulation • Top piscivorous wildlife have some of the highest levels Source: USGS modified from Cleckner et al. 1998.

  6. Wetlands and Mercury • Methylmercury production. • Source of methylmercury for freshwaters. • Sink and source

  7. Hg0 Hg Hg2+ Hgp

  8. Mercury concentrations in wetlands associated with coal-fired power plants (CFPPs) Richard Halbrook and Scott Weir Cooperative Wildlife Research Laboratory, Department of Zoology Southern Illinois University, Carbondale, Illinois

  9. Objectives • Preliminary information on total mercury (THg) in wetlands associated with coal-fired generating plants in Illinois • H1: Sediment and tadpole THg will be higher downwind than upwind, and that concentrations will increase with increasing distance downwind • H2: Sediment and tadpole THg concentrations will be positively correlated • Specific protocols for monitoring mercury concentrations in wetland habitats

  10. Selection of Power Plants • Plants were selected on the following factors: • Mercury emissions • Prevailing wind data • Suitable wetlands • The plants selected are: Joppa, Baldwin, Newton, and Southern Illinois Power Cooperative (SIPC)

  11. Sample Collections • 45 total wetlands in May and June 2007 • 12 wetlands sampled from Baldwin and SIPC, 11 from Joppa, and 10 from Newton • 3 upwind and between 3-5km • 9 downwind • Range: 3-5km, 8-10km, and 13-15km

  12. Map of Wetlands, IL counties, CFPPs

  13. Collection Methods • Sediment sampled with core augers • 3 samples from each wetland • Temperature (ºC) • Tadpoles sampled with dip nets • Species, stage, mass, length

  14. Sediment Variables • Oxidation-reduction potential • pH • Texture

  15. Mercury Analysis • Total Hg in tadpoles determined using a Hydra AF cold vapor mercury analyzer. • Tadpole digested by EPA method 245.7. • Sediment digested by EPA method 3051A. Analyzed at ISTC.

  16. Statistics • SAS (v 9.1) • Normality, Shapiro-Wilks • Analysis of covariance • ANOVA • Pearson Correlation (Bonferroni Correction)

  17. Sediment Results

  18. Upwind vs Downwind

  19. Tadpole Results (29 ponds)* *Mean + SE (n)

  20. Tadpole Results

  21. Tadpole upwind vs downwind

  22. Concentrations of importance AEisler 1987 BTerhivuo et al. 1984 CMacDonald et al. 2000 DHealth Canada 2007

  23. Correlations of Tadpole Variables * = p < 0.10, *** = p < 0.01 (Bonferroni correction)

  24. Tadpoles in the field

  25. Other CFPP studies

  26. Using tadpoles as bioindicators

  27. Conclusions • Preliminary information on total mercury (THg) in wetlands associated with coal-fired generating plants in Illinois • H1: Sediment and tadpole THg will be higher downwind than upwind, and that concentrations will increase with increasing distance downwind (Newton CFPP Only) • H2: Sediment and tadpole THg concentrations will be positively correlated (Rejected) • Develop Specific protocols for monitoring mercury concentrations in wetland habitats

  28. Management Implications • Concentrations of THg measured in sediment and tadpoles in wetlands surrounding Newton, Baldwin, Joppa, and SIPC CFPPs were are below levels of concern

  29. Acknowledgements • Illinois Sustainable Technology Center • Gary Bordson and the metals group at ISTC • Marvin Piwoni • Cooperative Wildlife Research Lab • Department of Zoology and Graduate School

  30. Questions?

  31. Conclusions • With the exception of Newton, CFPPs did not have a significant pattern of THg concentrations in ponds 3-15 km downwind • Tadpole THg was negatively correlated with length

  32. Sediment THg and distance

  33. Sediment Variables A = Pond means were used in these correlations *** = p < 0.01 (Bonferroni correction)

  34. Texture

  35. Mercury and Amphibians • MeHg • Hg2+ • 200-400 ng/g THg body burden • Concentrations similar to fish

  36. Local vs Regional vs Global • Contradicting results regarding the local effects of coal-fired power plants • Studies have reported local impacts • Some have stated that local impacts are overestimated • Atmospheric lifespan of mercury species

  37. Quality Assurance/Quality Control • Laboratory Blanks • Laboratory Reagent Spikes • Replicates • Sediment Only: • Matrix Spike • Reference Material • Tadpole Only: • Matrix Quad Study

  38. Tadpoles are kind of a pain • Feeding behavior • Predation escape • Metamorphosis/Physiology

  39. Newton Power Plant