1. Mercury Toxic trace element Occurs naturally Anthropogenic sources
Methyl form of most concern
So Ill start with a little background information about mercury. Im sure we have all heard about mercury in the news and if you follow environmental pollution at all. Mercury is a toxic trace element that occurs naturally at low levels. Mercury is an unusual metal as you can see in the picture in the background. Mercury can exist as a solid, liquid, and gas. It is very dense, and unlike many other metals, it will volatilize easily. Anthropogenic sources have increased mercury concentrations even in areas that are remote and removed from sources of mercury contamination. The methylmercury form is the most toxic, and the form that biomagnifies up the food chain.

2. Natural sources
Hg0
There are many sources of natural emissions of mercury such as volcanic eruptions, forest fires, and weathering of exposed cinnabar (or mercury (2) sulfide). These sources all release mercury mainly in the elemental form. Elemental mercury will then deposit on terrestrial and aquatic habitats. As stated earlier, mercury will easily volatilize, and mercury dissolved in water can volatilize and become re-emitted to the atmosphere when certain factors favor the chemical reaction.

3. Anthropogenic Sources
Hg0
Hg2+
Hgp
This contrasts with anthropogenic sources of mercury. Again, there are several sources of anthropogenic emissions of mercury into the environment including waste incineration, oil refinery, and CFPPs. Historically there are many sources of mercury that are no longer widely used including seed-coating fungicides, chlor-alkali plants, and gold mining practices. Anthropogenic sources can release mercury in three forms, predominately. Elemental mercury, Divalent mercury (inorganic mercury) and particulate-bound mercury. Particulates are solid particles suspended in a gas. These different forms have different half-lives in the atmosphere which I will discuss momentarily. These forms will also deposit in terrestrial and aquatic systems.

4. Mercury in the Environment
Inorganic Hg is now the predominant source of methylated mercury
Fossil fuel burning
Divalent mercury is now considered the largest source of methylated mercury in the environment. Historically, methylated mercury has come from fungicides, organomercurials used in industry, and and the EPA estimated that over 1/3 of anthropogenic emissions of mercury in the US came from CFPPs.

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

6. Wetlands and Mercury Methylmercury production.
Source of methylmercury for freshwaters.
Sink and source
We are interested in looking at ponds and wetlands, because wetlands (and ponds that dry frequently) are active sites of mehg production. Then during flood events, the mercury in the wetland system can be released into other freshwaters in the watershed. In this way, wetlands act as both a sink and a source of mercury in the environment. In addition, there have been few reports of the actual mercury concentrations in wetlands, most studies focus on lakes, rivers, or terrestrial soil. Amphibians are good vertebrate bioindicators for wetlands because they are present in both permanent ponds and ephemeral spring wetlands in high numbers. Some species inhabit ponds as tadpoles year-round before reaching metamorphosis.

7. Hg0 Hg
Hg2+
Hgp

8. Mercury concentrations in wetlands associated with coal-fired power plants (CFPPs)
Thanks everyone for coming out. Id like to acknowledge my advisors Drs Halbrook and Sparling for this opportunity. Ill be speaking about my masters research looking at spatial patterns (or lack thereof) in ponds surrounding coal-fired power plants, or what I will refer to as CFPPs for the rest of the talk.
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
That leads me to my objectives which you can read there. Essentially, my project was funded to go out and determine how much mercury contamination is in wetlands, and to determine if there is any effect of power plant on this contamination. Also my project lays out specific protocols for future studies to monitor 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)
I chose power plants based on how much mercury the plant emitted in the recent past, the prevailing wind direction around the plant, and if the plant had enough suitable wetlands in the vicinity for study. When I say suitable, I mean wetlands large enough to contain large tadpole species (i.e. ranids). Based upon these factors, Joppa, Baldwin, Newton, and SIPC were chosen for study.

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
So here we have a map of my sampling locations. This is Newton power plant. The star on these maps indicate the power plant, and the black line indicates overall prevailing wind direction calculated by NOAA for the past 80s years in that area. Also shown are the available wetlands in the area. Circles represent ponds and wetlands chosen for study. As I show the other plants Ive chosen, I want to comment on prevailing wind direction briefly. For three of these plants, you will note a strong southerly wind direction. While there is some variation in wind direction across months, for these plants, there is a very strong southerly wind direction. The one exception is Baldwin power plant. This plant has a WNW prevailing wind direction. However, during the summer months, the prevailing wind direction changes from WNW to S. So this may be a potential source of error, we chose to stick with the WNW direction, because that was the overall prevailing wind direction.

13. Collection Methods Tadpoles sampled with dip nets
Sediment sampled with core augers
3 samples from each wetland
Temperature (ºC)
Tadpoles sampled with dip nets
Species, stage, mass, length
I sampled sediment with a ___” core auger.

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
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)*
Bullfrog
Green Frog n
Homogenized
(35)a
(36)ab 71
Whole
(13)a
(16)b 29 48 52
100
*Mean + SE (n)

20. Tadpole Results

21. Tadpole upwind vs downwind

22. Concentrations of importance
Background conc
Current Study
Concentrations of concern
Sediment THg
20-60 ng/g (dw)A
8-82 ng/g (dw)
180 ng/g (dw)C
Aquatic Vertebrates THg
<80 ng/g (ww)B
5-318 ng/g (ww)
500 ng/g (ww)D
AEisler 1987
BTerhivuo et al. 1984
CMacDonald et al. 2000
DHealth Canada 2007

23. Correlations of Tadpole Variables
THg
Gosner Stage
Total Length (mm)
Weight (g) 1
-0.25*
-0.47***
0.71***
-0.39***
0.59***
0.81***
* = p < 0.10, *** = p < 0.01 (Bonferroni correction)

24. Tadpoles in the field Author Location Species Tissue Mercury conc
Current study
Illinois
Bullfrog Green frog
Whole body
63.2 ng/g ng/g
Burger and Snodgrass 2001
Savannah River, SW Carolina
Southern leopard frog
Body, Tail, Digestive tract
< ng/g DL
Bank et al. 2007
Acadia National Park, Maine
Whole body composite
19.1 ng/g ng/g
Unrine et al. 2005
Savannah River, W Carolina
Carcass Gut
184 ng/g (dw) ng/g (dw)
Byrne et al. 1975
Yugoslavia
Unspecified
410, 490 ng/g

25. Other CFPP studies Author Place Biological Unit Distance from CFPP
Species
Conclusions
Anderson and Smith 1977.
Illinois
1 Lake, Terrestrial soil
< 15 km
Many fish species
Soil sig. > downwind, Lake sed > after ops began, Fish conc very low
Wangen and Williams 1978.
New Mexico
Terrestrial Soil
8-120 km
N/A
Concentration as a function of distance were not significant for 9 elements
Crockett and Kinnison 1979
Arizona
< 30 km
No pattern in concentric rings
Pinkney et al 1997.
Maryland
Ponds km
Fish (bluegill, green sunfish, largemouth bass)
No pattern in concentric rings.Field results did not match model
Current Study
Ponds/Wetlands
Bullfrog, green frog larvae
No pattern for 3 of the CFPPs, Slight pattern downwind of Newton CFPP

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
That leads me to my objectives which you can read there. Essentially, my project was funded to go out and determine how much mercury contamination is in wetlands, and to determine if there is any effect of power plant on this contamination. Also my project lays out specific protocols for future studies to monitor 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
Sediment THg
Temperature (°C) pH
Redox potential
Pond area (m2)A
Tadpole THgA 1
-0.16
-0.21
-0.22
0.24
0.16
-0.85
0.01
-0.26
0.23
-0.33
-0.05
-0.41
0.35
-0.14
A = Pond means were used in these correlations
*** = p < 0.01 (Bonferroni correction)

34. Texture

35. Mercury across taxa Mammals Birds Amphibians Mechanism
MeHg causes central nervous system damage
Central nervous system damage
Neurotoxicity (?)
Physiological effects
Behavioral impairment: anorexia, lethargy
Weight loss, muscular incoordination
Adults: ? Tadpoles: swimming behavior
Reproduction
Readily crosses placental barrier
Reduced hatchability and clutch size, eggshell thinning
Effects on embryos (?)
Mercury has been studied extensively in mammals and birds, but has rarely been studied in amphibians or reptiles. In mammals MeHg disrupts central nervous system function. It can create behavioral impairment such as anorexia, and lethargy. In addition, it will readily cross the placental barrier and concentrate in the fetal brain disrupting fetal development. Likewise, in birds mercury causes central nervous system disruption. This has been reported to manifest itself as weight loss, and muscular incoordination. Its reproductive effects in birds includes decreased hatchability and clutch size, and can cause eggshell thinning. The effects of mercury on amphibians is less well known, and the few studies that are out there involve water concentration exposure which may not be a relevant way to determine toxicity for frogs, Ill discuss this more in my discussion. Few studies (only one that I have found) actually report body burdens, which I can compare to my findings. The mechanism of toxicity hasn’t been studied, but it is assumed to be neurotoxic as it is in other taxa. The physiological manifestations of toxicity has not been studied in adult frogs. In tadpoles some reports have found disrupted swimming behavior including irritative movements (don’t ask me what that means, the authors don’t specify). Many of these reports are in small journals and do not include the detail needed for sophisticated analyses. There have been some reports of effects on embryos, but it is mostly speculation and these studies have only determined mortality attributable to mercury exposure.

36. Mercury and Amphibians
MeHg
Hg2+
ng/g THg body burden
Concentrations similar to fish
So as I say that, lets get into some specifics about mercury and amphibians from the sparse data that is out there. As in other taxa, methylmercury is more toxic to amphibians and can cause mortality at much lower concentrations. At 50 ppb water concentration, all tadpoles exposed died, and at 1-10 ppb, tadpoles showed lethargy and did not develop into adults after 4 months of observation. Toxicity from inorganic mercury can vary drastically across species. The LC50 values for tadpoles exposed to Inorganic mercury in water range from about 1 to 67 ppb. Interestingly ranid frogs appear to be less sensitive to mercury, which is the opposite to what has been found with other contaminants such as pesticides.
One study that fed tadpoles diet dosed with mercury concentrations ranging from ppb, found that tadpoles had a body burden of ng/g dry weight. And tadpoles with this body burden showed ecologically adverse effects include increased mortality, malformations, and increased time to tail reabsorption. The authors state that the concentration in the diet has been reported in areas with only depositional sources of mercury, and that deposition of mercury alone could accumulate to concentrations that affect amphibians.

37. 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
However, there has been some contention in the literature about the local and regional effects of CFPPs smokestack emissions. Some studies have reported that CFPPs are having local impacts on freshwater ecosystems, and the EPA report to congress in 1997 also stated that CFPPs can have local impacts. However there have been other studies that have found this to be an overestimation of the effects of CFPPs, and insist that CFPPs have only regional-global impacts. This is intricately linked to the lifespan of mercury species emitted to the atmosphere.

38. Quality Assurance/Quality Control
Laboratory Blanks
Laboratory Reagent Spikes
Replicates
Sediment Only:
Matrix Spike
Reference Material
Tadpole Only:
Matrix Quad Study
All QA/QC results were within acceptable limits

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

40. Newton Power Plant