Download Mercury Concentrations in Wetlands Associated With Coal

Mercury
 Toxic
trace
element
 Occurs naturally
 Anthropogenic
sources
 Methyl form of
most concern
Natural sources
0
Hg
Anthropogenic Sources
Hg2+
Hg0
Hgp
Mercury in the Environment
Inorganic Hg is now
the predominant
source of methylated
mercury
 Fossil fuel burning

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
Hg0
Hg
Hgp
Hg2+
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
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
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)
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
Collection Methods

Sediment sampled with core
augers
3 samples from each wetland
 Temperature (ºC)

 Tadpoles
sampled
with dip nets
 Species, stage,
mass, length
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)
log Sediment THg (ng/g dry weight)
Sediment Results
1.8
1.6
1.4
Baldwin
Joppa
SIPC
Newton
1.2
1
2
3
Range
4
Upwind vs Downwind
log Sediment THg (ng/g dry weight)
2.0
Downwind
Upwind
*
1.5
1.0
0.5
3
7
1
7
3
9
2
6
0.0
Baldwin
Joppa
SIPC
Newton
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
n
*Mean + SE (n)
48
52
100
Tadpole Results
log Tadpole THg (ng/g wet weight)
2.0
1.8
1.6
1.4
Baldwin
Joppa
SIPC
Newton
1.2
1
2
3
Range
4
Tadpole upwind vs downwind
log Tadpole THg (ng/g wet weight)
2.5
Downwind
Upwind
2.0
1.5
1.0
0.5
2
4
4
1
6
2
3
0.0
Baldwin
Joppa
SIPC
Newton
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
AEisler
1987
BTerhivuo et al. 1984
CMacDonald et al. 2000
DHealth Canada 2007
5-318 ng/g (ww) 500 ng/g (ww)D
Correlations of Tadpole Variables
THg
Gosner Stage
Total Length
(mm)
THg
1
Gosner Stage
-0.25*
1
Total Length
(mm)
-0.47***
0.71***
1
Weight (g)
-0.39***
0.59***
0.81***
* = p < 0.10, *** = p < 0.01 (Bonferroni correction)
Weight (g)
1
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
Acadia
National Park,
Maine
Savannah
River, W
Carolina
Bank et al.
2007
Unrine et al.
2005
Byrne et al.
1975
Yugoslavia
Southern
leopard frog
Body, Tail,
< 0.200 ng/g
Digestive tract
DL
Bullfrog
Green frog
Whole body
composite
19.1 ng/g
25.1 ng/g
Southern
leopard frog
Carcass
Gut
184 ng/g (dw)
1275 ng/g (dw)
Unspecified
Whole body
410, 490 ng/g
Other CFPP studies
Author
Anderson and
Smith 1977.
Place
Illinois
Biological Unit
1 Lake,
Terrestrial soil
Distance from
CFPP
< 15 km
Species
Conclusions
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
Terrestrial Soil
< 30 km
N/A
No pattern in
concentric rings
Pinkney et al
1997.
Current Study
Maryland
Illinois
Ponds
Ponds/Wetlands
3 - 15 km
Fish (bluegill,
No pattern in
green sunfish, concentric rings.Field
largemouth results did not match
bass)
model
3 - 15 km
No pattern for 3 of the
Bullfrog, green CFPPs, Slight pattern
frog larvae downwind of Newton
CFPP
log pond mean sediment THg (ng/g dry weight)
Using tadpoles as bioindicators
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
0.8
1.0
1.2
1.4
1.6
1.8
2.0
log pond mean tadpole THg (ng/g wet weight)
2.2
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
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
length
THg was negatively correlated with
Sediment THg and distance
log Sediment THg (ng/g dry weight)
1.8
10
1.7
9
9
10
3
4
1.6
1.5
1.4
1.3
1.2
1
2
Range
Sediment Variables
Sediment THg
Temperature
(°C)
pH
Redox
potential
Pond area
(m2)A
Sediment THg
1
Temperature
(°C)
-0.16
1
pH
-0.21
-0.22
1
Redox
potential
0.24
0.16
-0.85
1
Pond area
(m2)A
0.01
-0.26
0.23
-0.33
1
Tadpole THgA
-0.05
-0.41
0.35
-0.14
0.01
A
= Pond means were used in these correlations
*** = p < 0.01 (Bonferroni correction)
Tadpole THgA
1
Texture
log sediment THg (ng/g dry weight)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
6
15
2
1
13
1
20
8
0.0
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m
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m
loa
m
loa
a
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nd
nd
la
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sa
y
nd
sa
s
yc
d
an
la
m
oa
l
y
sa
nd
m
oa
l
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am
t lo
sil
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
Readily crosses
placental barrier
Reduced
hatchability and
clutch size,
eggshell thinning
Effects on embryos
(?)
Reproduction
Mercury and Amphibians
MeHg
Hg2+
200-400 ng/g
THg body
burden
Concentrations
similar to
fish
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
Quality Assurance/Quality Control
 Laboratory
Blanks
 Laboratory Reagent
Spikes
 Replicates
Sediment Only:
Matrix Spike
Reference
Material
Tadpole Only:
Matrix Quad
Study
Tadpoles are kind of a pain
 Feeding
behavior
 Predation
escape
 Metamorphosis
/Physiology
Newton Power Plant
2.0
Sediment
Tadpole
log THg (ng/g)
1.8
1.6
1.4
1.2
1.0
1
2
3
Range
4