1 / 40

Mercury

Mercury. Toxic trace element Occurs naturally Anthropogenic sources Methyl form of most concern. Natural sources. Hg 0. Anthropogenic Sources. Hg 0. Hg p. Hg 2+. Mercury in the Environme nt. Inorganic Hg is now the predominant source of methylated mercury Fossil fuel burning.

elina
Download Presentation

Mercury

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  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

More Related