Transcript Mercury_Dgay.ppt

Atmospheric Mercury Deposition, A
Global Concern
David Gay
NADP Program Office, University of Illinois, Champaign, IL USA
[email protected]
Talk Outline
• Why it is important to measure Hg deposition?
• Overview of mercury deposition monitoring
• Measurements
o in North America, and
o a few in Mexico
• Some Results.
Why
it is important to measure Hg
deposition?
The Problem is not
Elemental Mercury…
(its Methyl Mercury)
Mercury, a Health Problem
• Children
• Women of child-bearing age (Hg passed on to fetus)
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•
Completely absorbed by the human gastrointestinal tract
•
in utero damage:
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–
•
readily transported across the placenta and absorbed by the developing fetus
have no blood-brain barrier to mercury
Biological persistent
–
half-life in human bloodstream is about 50 days
•
Causes severe neurological damage in infants and children
•
Incorporation in proteins results in abnormal molecular structure
and affects cellular structure and function
•
Also linked to increased risk of cardiovascular & kidney disease in adults
Examples….
• Industry
• “Mad Hatters”
• With very high concentrations in water
• 1960s Japan, daily fish consumption near industrial processing
• Minimata, 111 deaths
• Nigata, 120 deaths
• 1970s, Iraq and contaminated grain
• alkyl mercury fungicide seed mistakenly used to prepare bread
• more than 6,500 Iraqis hospitalized with neurological symptoms
• 459 died
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D. Gay, Schmeltz, Sharac, Nat. Tribal Conf. for Env. Management, Billings, MT, June 26, 2008,
Methylation is important in Wetlands & Sediments
Promotion of Methyl formation
•
wetlands & anoxic
waters/sediments
•
Geobactor sulfurreducens
Several sulfate-and ironreducing bacteria species
•
Sulfite present & active
sulfate reduction
•
Low light penetration
•
High DOC
•
Low oxygen (reduction)
•
Bioavailable inorganic Hg
Mercury in fish and marine mammals
BioDiversity Research Institute, 2012
www.cfsan.fda.gov/~frf/sea-mehg.html
0.3 ppm, EPA FDA
From E. Sutherland, USEPA
Fish Advisories in the United States
But it isn’t just humans….
Atmospheric Deposition is the key input of
Mercury in water bodies
• Hg source to water bodies is
overwhelmingly atmospheric
deposition and anthropogenic
“We conclude that nearly all of the mercury in fish in this seemingly pristine
landscape was derived from atmospheric deposition, that most of this
bioaccumulated mercury was from anthropogenic sources, and that both watershed
and lacustrine factors exert important controls on the bioaccumulation of
methylmercury.”
Sources of Atmospheric Mercury
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•
•
•
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•
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Coal combustion
Artisanal Gold Mining
Incineration
– Medical
– Trash
– Cremation
Industrial emissions (chlor-alkali)
Cement production
– Hg in lime, combustion coal, fly ash
Vinyl Chloride production
Metals Manufacturing
– Steel, iron, copper, zinc, lead
Mining
– Hg use in gold and silver mining
(amalgam formation)
– Mining for Hg
– taconite
Automobile Recycling
Mercury in Landfills
– Fluorescent lamps
– dental amalgams (also in sewers)
– Thermometers
– Batteries
– Discarded electrical switches
Gas/Oil/Diesel
– Production and combustion
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Volcanoes (St. Helens)
Naturally enriched ores/soils
– Plate tectonic boundaries
– Cinnabar (HgS), taconite, others
Soils and rocks (0.08 to 0.5 ppm in crust)
Evaporation
– Soils
– Fresh water and OCEANS
Natural forest fires
– Tree bark (wood fire places)
– soils
Volatilization from rocks?
Wind Blown reintroduction
–
–
•
Mine tailings
Industrial contaminated soils
Evolving Gases
–
–
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Mines, industrial areas
Waste facilities (municipal in particular)
Out of soil
Small Scale Artisanal Gold Mining?
Global Emissions of Mercury to the Atmosphere
American Emissions, include Gold Mining
Emissions Are Increasing
note the Asian Growth
EMEP, 2012
Evers, et al., 2012
Another Source….
•Estimated at 30% of total
annual US emission
•Forest fires >> ag. Fires
•Most emission from Alaska
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D. Gay, Schmeltz, Sharac, Nat. Tribal Conf. for Env. Management, Billings, MT, June 26, 2008,
U.S. Atmospheric Emissions
(metric tons per year)
Sources
Elemental
Mercury
Hg(0)
Oxidized
Mercury
Hg(II)
Particulate
Mercury
Hg(p)
Total
Mercury
Coal Burning
38
23
15
76 (45%)
Incinerators
11
33
11
55 (33%)
Other Point Sources
24
4
2
30 (18%)
Area Sources
7
0
0
7 ( 4%)
80 (48%)
60 (36%)
28 (16%)
168
Total
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D. Gay, Schmeltz, Sharac, Nat. Tribal Conf. for Env. Management, Billings, MT, June 26, 2008,
Global Emissions
(metric tons per year)
Source
Bergen et al.
Mason & Sheu
Lamborg et. al.
Seigneur et al.
Average
direct
2160
2400
.
2143
2234
re-emitted
2000
2090
4800
1067
2489
from land
500
810
1000
1805
1029
from oceans
1400
1300
600
1396
1174
6060
6600
6400
6411
6,368
Man-made
Natural
Total
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D. Gay, Schmeltz, Sharac, Nat. Tribal Conf. for Env. Management, Billings, MT, June 26, 2008,
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D. Gay, Schmeltz, Sharac, Nat. Tribal Conf. for Env. Management, Billings, MT, June 26, 2008,
How Mercury is Wet Deposited?
RGM
Hgp
RGM
Hgp
Hgo
Hgo
Oxidation (long lifetime)
rainout
Hgp
RGM
washout
sampler
NADP Measurement of Wet
Deposition and Gaseous
Concentrations
NADP’s Mercury Networks
http://nadp.isws.illinois.edu/MDN/
Mercury Deposition Network (MDN)
• Mercury sampling network (NADP)
o Scientific cooperative
o 1 of 4 networks
• Collect weekly precipitation-only wet deposition samples
• 110 North American sites
• Total and methyl Hg
• since 1996
Typical MDN Wet Deposition Site
Gaseous Measurement Stations
• Mercury speciation in the atmosphere
Tekran
Continuous Mercury
Speciation System
– elemental, reactive gaseous, particulate
(GEM, GOM, PBM2.5)
• Will estimate dry deposition flux
• With wet deposition flux (MDN)
• Meteorology & leaf wetness
• Land cover variables
Typical monitoring station
Operating AMNet Sites
New Trial Network, Litterfall Mercury
Mercury Deposition Network
Wet Deposition Results
Deposition (ug/m2seas)
Regional Average Mercury Deposition
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
MW
NE
OH
Region
SE
Win
All
Spr
Sum
Fall
Eastern North America Deposition Timelines
4500
Dep (ng/m2 week)
4000
3500
3000
NS01
2500
2000
PA90
1500
FL34
1000
Eastern North American Deposition Timelines
500
0
4500 7
Dep (ng/m2 week)
-9
ar
4000
M
8
l -9
u
J
9
-9
ec
D
-0
pr
A
1
0
pe
S
2
4
-0
n
Ja
05
ay
M
ct
O
6
-0
3500
3000
ME02
2500
2000
NY20
1500
MA01
1000
500
0
97
ar
M
8
l-9
Ju
9
-9
ec
D
-0
pr
A
1
0
pe
S
2
4
-0
n
Ja
05
ay
M
ct
O
-0
6
Trends in
Wet Deposition
All Seasons Mercury Concentration, Deposition,
and Precipitation Trends (1996-2005)
Depo.
Conc./Prec.
Decreases
Increases
One tail, a=0.05
Prestbo, E. M., and D. A. Gay, 2009. Atm. Env. 43 : 4223.
Mercury Concentration Trend Slopes
(percent/yr)
-3.1
-3.0
-1.8
-2.1
-2.5
-1.1
-3.2
-4.0
-5.2
-4.8
-3.1
-4.3
-2.2
-3.5
-1.4
-2.0
-4.0
Decreases
Increases
One tail, a=0.05
16.00
16.00
14.00
14.00
12.00
12.00
10.00
10.00
8.00
8.00
6.00
6.00
4.00
4.00
2.00
2.00
0.00
0.00
2000
2001
2002
2003
2004
average
14.00
Hg Deposition (ug/m2 year)
Hg Concentration (ng/L))
Great Lakes Mercury Wet Concentration and Deposition
2005
2006
2007
2008
2009
2010
median
14.00
12.00
12.00
10.00
10.00
8.00
8.00
6.00
6.00
4.00
4.00
2.00
2.00
0.00
0.00
2000
2001
2002
2003
2004
average
2005
2006
median
2007
2008
2009
2010
Net Change, Hg Concentrations 2002-2008 (ng/L)
Risch et al., 2012
Net Change in Deposition, 2002-2008 (ug/m2)
Risch et al., 2012
Gaseous Measurements
Gaseous Elemental Mercury
Seasonality of Gaseous Elemental Mercury
(2009 to 2011)
Stem and whisker plots of average mercury atmosphericOM,
a) G
and b) P
BM, for each AMNet site
AMNet Site Groupings
GOM
PBM2.5
Litterfall
Litterfall Estimates Around the Great Lakes
Risch et al, 2012
Litterfall dry dep.
Wet Dep.
Plans for Asia
Thank you.
Atmospheric Mercury Deposition, A
Global Concern
David Gay
NADP Program Office, University of Illinois, Champaign, IL USA
[email protected]