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.

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.

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.

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.

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.

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.

Hg0 Hg Hg2+ Hgp

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

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.

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.

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

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.

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.

Sediment Variables Oxidation-reduction potential pH Texture

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.

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

Sediment Results

Upwind vs Downwind

Tadpole Results (29 ponds)*   Bullfrog Green Frog n Homogenized 56.80 + 6.6 (35)a 45.46 + 5.9 (36)ab 71 Whole 86.52 + 24.8 (13)a 28.23 + 3.7 (16)b 29 48 52 100 *Mean + SE (n)

Tadpole Results

Tadpole upwind vs downwind

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

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)

Tadpoles in the field Author Location Species Tissue Mercury conc Current study Illinois Bullfrog Green frog Whole body 63.2 ng/g 45.1 ng/g Burger and Snodgrass 2001 Savannah River, SW Carolina Southern leopard frog Body, Tail, Digestive tract < 0.200 ng/g DL Bank et al. 2007 Acadia National Park, Maine Whole body composite 19.1 ng/g 25.1 ng/g Unrine et al. 2005 Savannah River, W Carolina Carcass Gut 184 ng/g (dw) 1275 ng/g (dw) Byrne et al. 1975 Yugoslavia Unspecified 410, 490 ng/g

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 3 - 15 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

Using tadpoles as bioindicators

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.

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

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

Questions?

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

Sediment THg and distance

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)

Texture

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.

Mercury and Amphibians MeHg Hg2+ 200-400 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 1500-3000 ppb, found that tadpoles had a body burden of 200-400 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.

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.

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

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

Newton Power Plant