exposure and effects of mercury on terrestrial wildlife david evers biodiversity research institute...
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Exposure and effects of mercury on terrestrial wildlife
David Evers BioDiversity Research Institute
Gorham, Maine
BioDiversity Research Institute 2
Presentation Outline
1. Understanding the where, what, why of biotic Hg• Geographic context• Factors related to Hg interpretation
2. Developing national monitoring standards • Potential national indicator species• Why use the loon?
3. Risk Characterization (weight of evidence approach)• Exposure profile results (spatially explicit)• Hazard profile results (individual & population level)
4. Linking science to policy• WCV Hg Model• Southeastern NH “hotspot”
5. What’s next?
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What parts of the country are at greatest risk?
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Geographic trend of Hg in a standard species: Common Loon (n>2000 individuals)*
*Evers et al. 1998, Environ. Tox. Chem.; Evers et al. 2003, Ecotoxicology
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How is MeHg availability distributed within the Northeast?
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Sampling Effort:1992-2003; n>1,800
Evers et al. In Press, Ecotoxicology
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What do tissues indicate?
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Fish prey Hg strongly correlates with adult loon blood Hg (r2>0.72)*
y = 2.7485x + 0.3714
R2 = 0.7511
y = 3.65x + 0.5838
R2 = 0.7161
0
1
2
3
4
5
6
0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40
Cumulative total Hg levels for 4 sizes classes of fish (ww, ppm)
Co
mm
on
Lo
on
blo
od
to
tal H
g le
ve
l (w
w, p
pm
)Male (n=19)
Female (n=21)
* Scheuhammer and Blancher 1998, Hydrobiologia; Burgess and Hobson In Press. Hydrobiologia; Evers et al. In Press, Ecotoxicology
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Loon egg Hg strongly correlates with adult female blood Hg (r2=0.79)*
y = 1.5544x + 0.2238
R2 = 0.790
1
2
3
4
5
6
7
8
0 1 2 3 4 5Egg Hg (ug/g, ww)
Fe
ma
le B
loo
d H
g (
ug
/g, w
w)
* Evers et al. 2002. Ecotoxicology 12:69-81.
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Otter and mink fur Hg strongly correlates with brain (and liver) Hg*
* Yates et al. In Press, Ecotoxicology
y = 27.867x + 5.6631R2 = 0.6497
0
10
20
30
40
50
60
70
80
0 0.5 1 1.5 2 2.5 3
Brain total Hg (ppm, ww)
Fu
r to
tal H
g (
pp
m, f
w)
y = 36.284x + 4.2747R2 = 0.4563
0
5
10
15
20
25
30
35
40
0 0.5 1 1.5 2 2.5
Brain total Hg (ppm, ww)
Fu
r to
tal H
g (p
pm
, fw
)
MINK
OTTER
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What habitats are at greatest risk to higher trophic level biota?
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1. Aquatic systems Wetlands, particularly bogs Acidic lakes (<6.3)* Certain reservoirs (current USDA study) Urban estuaries (current USFWS study)
2. Terrestrial systems Mountaintops~ Areas deficient in Ca
(due to potential synergy)
*Meyer et al. 1995, Hydrobiologia~ Rimmer et al. In Press, Ecotoxicology
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Blood Hg levels in juvenile Bald Eagles, Maine
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Juve
nile
Blo
od
Hg
(u
g/g
, ww
)
Marine(n = 39)
Estuary(n = 7)
River(n = 8)
Lake(n = 49)
A A B C
Evers et al. In Press, Ecotoxicology
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0
0.5
1
1.5
2
2.5
3
Blo
od
Hg
(u
g/g
, w
w)
MarineJ A
(n =8, 4)
EstuaryJ A
(n = 31, 12)
RiverJ A
LakeJ A
(n = 64, 47)
Blood Hg levels in adult and juvenile Belted Kingfishers, Maine
A B B C
Evers et al. In Press, Ecotoxicology
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Factors confounding interpretation of Hg exposure
0
0.5
1
1.5
2
2.5
3
3.5
4
Blo
od
Hg
(u
g/g
, ww
)
TRESF M(n= 38, 12)
BEKIF M(n = 56, 60)
COLOF M
(n = 364, 406)
0
0.5
1
1.5
2
2.5
3
3.5
Blo
od
Hg
(u
g/g
, ww
)
SOSPJ A
(n = 17, 16)
TRESJ A
(n = 73, 53)
BEKIJ A
(n=184, 116)
COMEJ A
(n=69, 11)
COLOJ A
(n = 452, 786)
Age Class
SexEvers et al. In Press, Ecotoxicology
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Insectivorous songbird blood Hg level comparison
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
AMGO
(n = 12)
EABL
(n = 7)
YWAR
(n = 9)
WODU
(n = 5)
GRCA
(n = 6)
GCFL
(n = 4)
COYE
(n = 9)
S OS P
(n = 34)
WIFL
(n = 6)
S WS P
(n = 18)
TRES
(n = 9)
RWBL
(n = 6)
NOWA
(n = 2)
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*Rimmer et al. In Press, Ecotoxicology~Shriver et al. 2002, MDEP Unpubl. Rept.
R2 = 0.3113
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1 2 3 4 5 6 7 8 9
Age
Fe
ath
er
Hg
(p
pm
)
Mountains (ug/g, ww)*
New England: 0.08-0.27DR and Cuba: 0.03-0.42
0.2
0.3
0.4
0.5
0.6
0.7
0.8
NSTS SSTS
Urban Estuaries~Blood Hg (ug/g, ww)5 locations, southern ME
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What is the standard measuring stick?
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National indicators program*
National EPA-directed and cooperative process is currently targeting candidate species, based on (1) available information, (2) geographic representation, (3) at greatest risk, (4) logistical feasibility and (5) most interpretative of site (i.e., predictable feeding area/small home range).
Candidate Indicators:Lakes…. Common Loon & Bald EagleRivers…. Belted KingfisherMountains… Bicknell’s ThrushWetlands….. Tree SwallowEstuaries….. saltmarsh sparrows (SSTS, NSTS,
SESP)Inshore marine areas.. Common TernOffshore marine areas.. Leach’s Storm-Petrel
* Mason et al. In press. Environmental Science and Technology 39 & Wolfe et al. In press. SETAC book.
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Mink and River Otter as indicators of landscape level risk*
Yates et al. In Press, Ecotoxicology
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The Common Loon as a national indicator:
(1) monitoring exposure, (2) determining effects, & (3) relating at a population level
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Why the Common Loon?
1. High trophic level obligate piscivore (biomagnification);
2. “K-selected” life history strategy (bioaccumulation);
3. Complex and coordinated behaviors within pair;
4. Moderate to high sensitivity to stressors;
5. Logistically feasible (easily observed and individually identified over entire breeding period);
6. Matrices (i.e., blood and eggs) can represent a target area
7. High profile to public and therefore policymakers;
8. Demographic models developed based on >3,000 banded loons.
9. Documented individual and, potentially, population level impacts from MeHg ingestion (based on dosing studies* and long-term field investigations);
Meyer et al. per. com.
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Do current levels cause ecological impact?
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Rangeley Lakes Focal Study Site (44 lakes with 181 Loon Territories)
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Hazard Assessment for individuals; Does Hg impact individual loons? YES
• Physiological:• Significant relationship with increasing corticosterone & MeHg
• Behavioral (>2,500 hours of observation)~• Higher Hg levels sig. reduce time incubating
• Higher Hg levels cause adults to become lethargic (i.e., they spend sig. more time in low energy behaviors)
• Pharmacokinetics:• Recaptured adults have 9% (males) and 5.6% (females) annual
increase in feather Hg levels+
• Recaptured juveniles have increasing (1-3%/day) Hg levels during the summer
*Olson et al. Conservation Ecology~Nocera and Diamond 1999; Conservation Ecology+Evers et al. 1998, Environ. Tox. Chem.
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0
10
20
30
40
50
60
Nest Sitting Forage Locomotion Preen Resting Agonistic
Behavior State
Pe
rce
nt
of
tim
e
Female Low (n=22)
Female mod (n=16)
Female Hi/Xhi (n=47)
Male Low (n=23)
Male Moderate (n=17)
Male Hi/Xhi (n=47)
•R•2 • = 0.230
•p = 0.037
•0%
•10%
•20%
•30%
•40%
•50%
•60%
•70%
•80%
•90%
•0.00 •1.00 •2.00 •3.00 •4.00 •5.00 •6.00 •7.00• Blood Hg (ppm, ww)
• Per
cent
tim
e ad
ults
(M
&F
) sp
ent
• in
Hig
h* e
nerg
ybeh
avio
rs
Behavioral impacts
Low Hg incubation time=99% of time
High Hg incubation time=85% of time
Male foraging time for
high Hg risk loons
is one-third that of
low Hg risk ones
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Population-level impacts from Hg; Is Hg harming loon populations? Likely
• Condition/Fitness:
– Measurements indicate a decline related to increasing Hg.• Flight feather asymmetry is significant in Maine’s breeding population –
the 3.5% mean may result in 15% less flight efficiency
• Recaptured high/xhigh adults show a sig. (p=0.03) body weight decline vs. low/mod (n=21).
• Egg weights have a sig. (p=0.02) decline as Hg levels increase*
• Reproductive Success:~
• Compared to low risk loon pairs, high risk pairs;• Significantly initiate 7% fewer nests
• Significantly hatch 31% fewer eggs
• Significantly fledge 40% fewer young
*Evers et al. 2003, Ecotoxicology~Evers et al. 2004, MDEP Unpbl. Rept.
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Impacts to reproductive success
0.76
1.22
0.740.68
0.76
0.99
0.65
0.49
0.71
0.84
0.68
0.41
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
•Nest (NP/TP) •Hatch (SY/NP) •Chick Survival (LY/SY) •Overall Productivity (LY/TP)
•Productivity Parameters
• Lo
on
Pro
du
ctiv
ity
Rat
es
•Low Risk (n=30 territories, 149 territory-years )
•Moderate Risk (n=58 territories, 330 territory-years)
•High Risk (n=46 territories, 394 territory-years)
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Hazard Assessment - Results
Matrix* Low Mod High Xhigh Reference
Fish** 0-0.1 0.1-0.2 0.2-0.4 >0.4 Barr 1986, Burgess and Hobson In Press
Eggs 0-0.5 0.5-1.3 1.3-2.0 >2.0 Evers et al. 2003
Blood-J 0-0.1 0.1-0.3 0.3-0.4 >0.4 Meyer et al. 1998***Blood-A0-1.0 1.0-3.0 3.0-4.0 >4.0 Nocera and Diamond 1999
Feather 0-9 9-20 20-30 >30 Thompson 1998
* Total Hg levels in ug/g, blood and eggs are ww and feathers are fw
** Represents 10-15 cm Yellow Perch, ww, whole body analysis
***Applies to 3-5 week old chicks only
LOAELNOAEL
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New England risk characterization Opportunistic and Random Sampling Design
84% 16%
57%
43%
27%
27%
39%
34%
84%
47%
42%
59%
51%
5%
14%
9%
9%
8%
12%
5%
3%
6%
7%
10%
5%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
ME (n=715)
REMAP (n = 116)
NH (n=479)
NY (n=201)
MA (n=37)
VT (n=86)
AK (n=57)
Mercury risk to Loon breeding population
low
mod
high
Xhigh
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Common Loon Population Model
Model Demographic parameters mostly known Needs to be spatially explicit
Will provide a test dose for Hg that is based on: Wild populations Population level
Results to date Lamda = 0.48 fledged
young/territorial pair Validated through NH
and VT long-term
datasets 0.92
0.94
0.96
0.98
1
1.02
1.04
1.06
1.08
1.1
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
# of female fleglings per TP
lam
bda
Positive Growth
Negative Growth
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Linking science to policy
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What is a WCV?
A procedure to estimate surface Hg water levels that will protect the viability of wildlife populations associated with aquatic resources
First developed and used in 1995 for the Great Lakes Water Quality Initiative (GLI)
An independently directed U.S. Congressional request in 1990 for a WCV (as mandated by the Clean Air Act) was developed by the U.S. EPA in a 1997 Report to Congress.
Parts of this report were published by Nichols and Bradbury as “Derivations of wildlife values for mercury” in the J. Toxicology and Environ. Health, 1999.
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Demographic Processes
WCV= {TD x [1/(UFLxUFAxUFS)]} x WTA WA + [(FD3xFAxBAF3) + (FD4xFAXBAF4)]
Tested Dose from toxicity studies with wildlife species (ug Hg/kg body weight/day
UFL=LOAEL-to-NOAEL UF UFA=species-to-species UF UFS=subchronic-to-chronic UF
Avg. species weight (kg)
Avg. daily volume of water consumed (L/day)
FD 3&4 =Fraction of diet from trophic level 3&4 FA=Avg. daily mass of food consumed (kg/day)
BAF 3&4 = aquatic life bioaccumulation factor for trophic level 3 & 4 (L/kg of MeHg in fish / MeHg in water)
0.92
0.94
0.96
0.98
1
1.02
1.04
1.06
1.08
1.1
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
# of female fleglings per TP
lam
bda
Positive Growth
Negative Growth0.92
0.94
0.96
0.98
1
1.02
1.04
1.06
1.08
1.1
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
# of female fleglings per TP
lam
bda
0.92
0.94
0.96
0.98
1
1.02
1.04
1.06
1.08
1.1
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
# of female fleglings per TP
lam
bda
Positive Growth
Negative Growth
Wildlife Criterion Value
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Test Dose
EPA WCV limitations Test dose is:
Based on mallards, non-piscivorous birds that are more sensitive to Hg toxicity because for evolutionary reasons;
Based on laboratory studies; Based on impacts to individuals.
Ingestion rates and BAF are quite generic and are not based on empirical data.
BRI WCV (response to limitations in EPA model) Test dose is:
based on a species that is sensitive to Hg toxicity and is exposed to Hg levels that are significantly higher than historical levels on freshwater lakes;
Based on in-field studies: Based on impacts to populations.
Ingestion rates and BAF are empirically measured parameters.
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Bioconcentration Factor1. Total Hg in unfiltered water related to yellow perch Hg (whole body, ww)
• BAF for Trophic Level 3 fish (5-15 cm) = 86,250• BAF for Trophic Level 4 fish (15-25 cm) = 156,330
2. Total Hg in unfiltered water related to perch or perch equivalents• Best relationship with 5-10 cm size class (explains 55% of variation)• Species-to-species conversion is 1.15 for centrarchids, golden shiner, trout
3. Water-fish MeHg relationship is being investigated in New York
y = 0.0579x + 0.0095
R2 = 0.5495
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500
Unfiltered water total Hg levels (ppt)
5-1
0 c
m f
ish
to
tal
Hg
le
ve
ls (
ww
, p
pm
)
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WCV for Hg based on population levels of the Common Loon
WCV Male Loon = 0.179 mg/kg/d x [1/3 x 1 x 2)]) x 5.95 kg
0.012 L/d + [(0.73) (1.19 kg/d x 86,250) + (0.27) (1.19 kg/d x 156,330)
WCV Male Loon = 1.418 ng/L
WCV Female Loon = 0.142 mg/kg/d x [1/3 x 1 x 2)]) x 4.71 kg
0.012 L/d + [(0.83) (0.943 kg/d x 86,250) + (0.17) (0.943 kg/d x 156,330)
WCV Female Loon = 1.204 ng/L
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Where do emission point sources have the greatest impact?
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Southeastern New Hampshire “hotspot”
1. Detected by USEPA atmospheric deposition models
2. Likely related to high Hg emissions from local municipal and hospital waste incinerators andcoal-burning power plants
3. Loon tissue Hg results (n=266 samples; 47 lakes)
4. Recent assessments show a decline in the biotic Hg signal
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Much is known….what’s next?
Determine Hg effect levels on wildlife (LOAELs)
Loon emphasis in Northeast (in situ) and Wisconsin (lab/in situ) Insectivorous bird emphasis in Northeast (in situ) and Patuxent
Wildlife Research Center (lab)
Further understand Hg relationships in systems (i.e., reservoirs) that do not follow NSRC models (long-term USDA NSRC grant)
Relate abiotic and biotic Hg levels with exposed shoreline Further explore biodilution, where plankton structure dictates
biomagnification Investigate the interaction among reservoirs with varying hydrology
and chlorophyll A levels
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Develop spatially-explicit wildlife criterion value (WCV) for Hg
In process for Maine (fourth year) and New York (second year) Vermont and New Hampshire??
Summarize Hg databases into a common database, model Hg relationships, and publish results
In process through the USDA’s Northeastern Ecosystem Research Cooperative (NSRC): Special double issue in Ecotoxicology published in early 2005
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Collaborators
FEDERAL GOVERNMENT
• U.S. Fish and Wildlife Service – New England Field Office and Office of Migratory Bird Mgmt.
• U.S. EPA – ORD Narragansett Office – Atlantic Ecological Div. & the New England Field Office
• U.S.D.A. – Northeastern Ecosystem Research Cooperative
• Canadian Wildlife Service
STATE GOVERNMENT
• Maine Dept. of Environ. Protection & Inland Fish and Wildlife
• Mass. Dept. Conserv. & Resour.
• NH Dept. of Environ. Service
• NY State Dept. of Environ. Cons.
• Vermont Dept. of Environ. Cons.
NON-PROFIT / UNIVERSITY
• Adirondack Coop. Loon Program
• Buffalo State College
• Loon Preservation Committee
• Maine Audubon Society
• Texas A&M Trace Element Res. Lab
• Tufts University
• Univ. of Pennsylvania
• Univ. of Southern Maine
• Vermont Inst. Of Natural Science
• Wildlife Conservation Society
INDUSTRY
• FPL Energy Maine Hydro
• New York State Energy Research and Development Authority