Mercury in the Environment

1
Mercury in the Environment Where Does the
Mercury in Fish Come From?
Mark Cohen NOAA Air Resources Laboratory 1315
East West Highway, R/ARL, Room 3316 Silver
Spring, Maryland, 20910, USA mark.cohen_at_noaa.gov h
ttp//www.arl.noaa.gov/ss/transport/cohen.html
Howard University Department of Chemistry
Seminar October 24, 2008, Washington D.C.
2
atmospheric deposition to the watershed
atmospheric deposition to the water surface
Humans and wildlife affected primarily by eating
fish containing mercury Best documented
impacts are on the developing fetus impaired
motor and cognitive skills
Mercury transformed by bacteria into
methylmercury in sediments, soils water, then
bioaccumulates in fish
adapted from slides prepared by USEPA and NOAA
3
Environmental Mercury Cycling -- Natural vs.
Anthropogenic

• Mercury (Hg) is an element... there is the same
  amount of mercury on Earth today as there always
  has been

• natural Hg cycle
• transported throughout the environment
• chemical transformations interconvert different
  mercury species

• This has always been going on, ... always has
  been Hg in fish

4
Pre-Industrial Global Mercury Cycling
Sunderland and Mason (2007). Global
Biogeochemical Cycles 21, 4022
5
GLOBAL MERCURY CYCLING
(note -106 moles 200 metric tons)
natural extraction from deep reservoirs, e.g.,
volcanoes
natural evasion from ocean
natural evasion from land
pre-industrial total mercury in atmosphere 8.0
x 106 moles
106 moles per year
natural dep to land
natural dep to ocean
Based on data presented in Sunderland and Mason
(2007) Global Biogeochemical Cycles 21 GB4022
6
Environmental Mercury Cycling -- Natural vs.
Anthropogenic

• Mercury (Hg) is an element... there is the same
  amount of mercury on Earth today as there always
  has been

• natural Hg cycle Hg is transported throughout
  the environment, and chemical transformations
  interconvert different mercury species

• This has always been going on, and there has
  always been Hg in fish

• But, we make some Hg unexpectedly bioavailable

• Most anthropogenic Hg is released as
  atmospheric emissions

• Hg in coal is released to the air when coal is
  burned
• Hg in other fuels is released to the air when
  they are processed and burned
• Hg in ores is released to the air during
  metallurgical processes
• Hg in products is released to the air when burned
  or landfilled after being discarded (e.g.,
  batteries, switches)

• Average, current atmospheric Hg deposition is 3x
  pre-industrial levels

• Evidence suggests that newly deposited Hg is more
  bioavailable

7
GLOBAL MERCURY CYCLING
(note -106 moles 200 metric tons)
natural extraction from deep reservoirs, e.g.,
volcanoes
natural evasion from ocean
natural evasion from land
pre-industrial total mercury in atmosphere 8.0
x 106 moles
106 moles per year
natural dep to land
natural dep to ocean
Based on data presented in Sunderland and Mason
(2007) Global Biogeochemical Cycles 21 GB4022
8
Natural vs. anthropogenic mercury? Studies show
that anthropogenic activities have typically
increased bioavailable Hg concentrations in
ecosystems by a factor of 2 10
9
What Influences Hg Levels in Fish?
10
The Biogeochemistry of Mercury in an Aquatic
Ecosystem

• Oxidized mercury Hg(II) required provided by
  atmospheric deposition of Hg(II) or in-situ
  oxidation
• Hg(II) transformed to MeHg (methyl-mercury) by
  sulfate-reducing bacteria under anoxic conditions
• Most commonly occurs in the top layers of the
  waterbodys sediment
• Methylation can also occur in the water column
  and in the watershed (e.g., wetlands)
• Me-Hg can bioaccumulate, other environmental
  forms of mercury do not
• Me-Hg is much more toxic than other environmental
  forms of mercury

Figure from presentation by Cindy Gilmour,
Smithsonian Environmental Research Center
11
What Influences Hg Levels in Fish?

• Current / past atmospheric and other Hg inputs to
  the fishs ecosystem

12
Evers, D. et al (2007). Biological Mercury
Hotspots in the Northeastern United States and
Southeastern Canada. BioScience 57, 29-43.
13
Evers, D. et al (2007). Biological Mercury
Hotspots in the Northeastern United States and
Southeastern Canada. BioScience 57, 29-43.
14
What Influences Hg Levels in Fish?

• Current / past atmospheric and other Hg inputs to
  the fishs ecosystem

• Biogeochemical factors influencing the degree of
  mercury methylation in the ecosystem (sulfate,
  dissolved organic carbon, pH, etc)

15
Mercury Sensitivity Map for Aquatic Ecosystems in
the Contiguous 48 United States
Metrics Used to Create Map Water Chemistry
pH, DOC, Sulfate, ANC, Total Hg,
MeHg Others Hydric Soils, Hg Deposition
from Myers et al. (2007) Science
16
What Influences Hg Levels in Fish?

• Current / past atmospheric and other Hg inputs to
  the fishs ecosystem

• Biogeochemical factors influencing the degree of
  mercury methylation in the ecosystem (sulfate,
  dissolved organic carbon, pH, etc)

• Food web structure of the waterbody and trophic
  level of species

17
Mercury Bioconcentration
Figure from Charley Driscoll, Syracuse University
18
What Influences Hg Levels in Fish?

• Current / past atmospheric and other Hg inputs to
  the fishs ecosystem

• Biogeochemical factors influencing the degree of
  mercury methylation in the ecosystem (sulfate,
  dissolved organic carbon, pH, etc)

• Food web structure of the waterbody and trophic
  level of species

• Age (size) of fish as fish age, they accumulate
  more and more mercury

19
Mercury concentration vs. length for Lake Erie
walleye and bass
From the Lake Erie LaMP (2002), for fish caught
in Lake Erie Block 1 (a particular subregion of
the lake). The Mercury Guidance of 0.45 ppm in
this figure is simply an illustrative threshold
used by the authors. (Figure 3 from NOAA Report
to Congress on Mercury in the Great Lakes)
20
What Influences Hg Levels in Fish?

• Current / past atmospheric and other Hg inputs to
  the fishs ecosystem

• Biogeochemical factors influencing the degree of
  mercury methylation in the ecosystem (sulfate,
  dissolved organic carbon, pH, etc)

• Food web structure of the waterbody and trophic
  level of species

• Age (size) of fish as fish age, they accumulate
  more and more mercury

• History of that particular fish

21
NOAA Fisheries, Office of Sustainable Fisheries,
National Seafood Inspection Laboratory Tony
Lowery, Spencer Garrett and colleagues

• total mercury in Gulf of Mexico recreational
  finfish
• reconnaissance survey to provide info for larger
  surveys

Slide content from Tony Lowery, NOAA
22
What Influences Hg Levels in Fish?

• Current / past atmospheric and other Hg inputs to
  the fishs ecosystem

• Biogeochemical factors influencing the degree of
  mercury methylation in the ecosystem (sulfate,
  dissolved organic carbon, pH, etc)

• Food web structure of the waterbody and trophic
  level of species

• Age (size) of fish as fish age, they accumulate
  more and more mercury

• History of that particular fish

• Knowledge gaps for Hg levels and reasons for
  levels
• freshwater (inland) fish -- LARGE UNCERTAINTIES
• estuarine marine fish -- VERY LARGE
  UNCERTAINTIES

23
Link Between Seawater Hg and Tuna Hg
Concentrations?
24
What Are Hg Levels in Fish?

• State Monitoring Programs
• Each states program is different
• Generally a limited number of waterbodies
• Generally a limited number of species
• Relatively infrequent (e.g., a given waterbody
  might be sampled once every 5 or 10 years)

• Federal Monitoring Programs (EPA, FDA, NOAA, )

• Recreational fishing / subsistence fishing - data
  for specific species in specific waterbodies
  These lead to localized fish advisories

25
Spatial Variation of Mercuryin Fish
(Standardized)
Mercury (ppm)
1.2 1.5
0.9 1.2
0.6 0.9
0.3 0.6
Slide from Steve Wente, USGS
lt 0.3
26
What Are Hg Levels in Fish?

• State Monitoring Programs
• Each states program is different
• Generally a limited number of waterbodies
• Generally a limited number of species
• Relatively infrequent (e.g., a given waterbody
  might be sampled once every 5 or 10 years)

• Federal Monitoring Programs (EPA, FDA, NOAA, )

• Recreational fishing / subsistence fishing - data
  for specific species in specific waterbodies
  These lead to localized fish advisories

• Surprisingly little data for commercial fish, and
  generally large variability

27
4.5
Mercury Levels in Commercial Fish and Shellfish
3.7
3.2
2.2
error bars show range of mercury concentrations
for a given species
Fish concentration data from NOAA and FDA.
Downloaded Sept 2008 from the EPA-FDA
fish-mercury website http//www.cfsan.fda.gov/f
rf/sea-mehg.html
28
What Are Hg Levels in Fish?

• State Monitoring Programs
• Each states program is different
• Generally a limited number of waterbodies
• Generally a limited number of species
• Relatively infrequent (e.g., a given waterbody
  might be sampled once every 5 or 10 years)

• Federal Monitoring Programs (EPA, FDA, NOAA, )

• Recreational fishing / subsistence fishing - data
  for specific species in specific waterbodies
  These lead to localized fish advisories

• Surprisingly little data for commercial fish, and
  generally large variability

• In most cases, difficult for the consumer to know
  how much mercury is in the fish they eat, other
  than an approximate, potential level

• New - Safe Harbors testing / certification
  program http//safeharborfoods.com

29
Public Health Context
30
Public Health Context

• Methyl-mercury is a developmental neurotoxin --
  risks to fetuses/infants

• Cardiovascular toxicity might be even more
  significant (CRS, 2005)

• Uncertainties, but mercury toxicity relatively
  well understood
• epidemiological studies, e.g., (a) Seychelles
  (b) Faroe Islands (c) New Zealand
• well-documented tragedies

31
Public Health Context

• Methyl-mercury is a developmental neurotoxin --
  risks to fetuses/infants

• Cardiovascular toxicity might be even more
  significant (CRS, 2005)

• Uncertainties, but mercury toxicity relatively
  well understood
• well-documented tragedies (a) Minimata (Japan)
  1930 to 1970 (b) Basra (Iraq), 1971
• epidemiological studies, e.g., (a) Seychelles
  (b) Faroe Islands (c) New Zealand

• Critical exposure pathway methylmercury from
  fish consumption

Note Hg in fish muscle tissue, so cant easily
avoid it (PCBs, Dioxins and other hydrophobic
contaminants concentrated in fat)
32
Mean Methylmercury Concentrations for "Top 24"
Types of Fish Consumed in U.S. Commercial Seafood
Market
Source of data Carrington and Bolger,
2002 Based on slide from Elsie Sunderland,
USEPA
33
Percent Contribution to per capita Methylmercury
Intake by Fish Type for "Top 24" Types of Fish in
U.S. Commercial Seafood Market
Source of data Carrington and Bolger,
2002 Based on slide from Elsie Sunderland,
USEPA
34
Blood Hg (ug/L) - U.S. Women ages 6-49based on
NHANES data (1999-2002)
Source of data Mahaffey et al., 2005 Based on
slide from Elsie Sunderland, USEPA
35
Total Mercury Levels in Women,Aged 16-49by
Weekly Fish Consumption Levels
of women
Mercury Levels (ug/L)
Slide from Kate Mahaffey
36
Public Health Context

• Methyl-mercury is a developmental neurotoxin --
  risks to fetuses/infants

• Cardiovascular toxicity might be even more
  significant (CRS, 2005)

• Uncertainties, but mercury toxicity relatively
  well understood
• well-documented tragedies (a) Minimata (Japan)
  1930 to 1970 (b) Basra (Iraq), 1971
• epidemiological studies, e.g., (a) Seychelles
  (b) Faroe Islands (c) New Zealand

• Critical exposure pathway methylmercury from
  fish consumption

• Toxicity believed to be occurring at current
  exposures

37

• Based on the NHANES national survey,
  approximately 6 of women of child-bearing age in
  the U.S. have blood mercury levels above the
  EPAs Reference Dose for potential adverse
  fetal/infant health impacts (3600 women tested
  nationwide)

Jones et al. (2004). Blood mercury levels in
young children and childbearing-aged women -
United States, 19992002. Morbidity and Mortality
Weekly Report (CDC). 53(43)10181020.

• Controversy over reference dose and how to
  interpret it

• 4,000,000 U.S. live births / yr x 6
• 240,000 newborns potentially at risk / yr

• NHANES is not designed to capture vulnerable
  sub-populations with unusually high fish
  consumption and mercury exposure

38
Public Health Context

• Methyl-mercury is a developmental neurotoxin --
  risks to fetuses/infants

• Cardiovascular toxicity might be even more
  significant (CRS, 2005)

• Uncertainties, but mercury toxicity relatively
  well understood
• well-documented tragedies (a) Minimata (Japan)
  1930 to 1970 (b) Basra (Iraq), 1971
• epidemiological studies, e.g., (a) Seychelles
  (b) Faroe Islands (c) New Zealand

• Critical exposure pathway methylmercury from
  fish consumption

• Toxicity believed to be occurring at current
  exposures

• Widespread fish consumption advisories

39
Mercury Fish Consumption Advisories are Ubiquitous
40

• 1. Do not eat Shark, Swordfish, King Mackerel, or
  Tilefish because they contain high levels of
  mercury.
• 2. Eat up to 12 ounces (2 average meals) a week
  of a variety of fish and shellfish that are lower
  in mercury.
• Five of the most commonly eaten fish that are low
  in mercury are shrimp, canned light tuna, salmon,
  pollock, and catfish.
• Another commonly eaten fish, albacore ("white")
  tuna has more mercury than canned light tuna.
• So, when choosing your two meals of fish and
  shellfish, you may eat up to 6 ounces (one
  average meal) of albacore tuna per week.
• 3. Check local advisories about the safety of
  fish caught by family and friends in your local
  lakes, rivers, and coastal areas. If no advice is
  available, eat up to 6 ounces (one average meal)
  per week of fish you catch from local waters, but
  don't consume any other fish during that week.
• Follow these same recommendations when
• feeding fish and shellfish to your young child,
• but serve smaller portions.

March 2004
41
Public Health Context

• Methyl-mercury is a developmental neurotoxin --
  risks to fetuses/infants

• Cardiovascular toxicity might be even more
  significant (CRS, 2005)

• Uncertainties, but mercury toxicity relatively
  well understood
• well-documented tragedies (a) Minimata (Japan)
  1930 to 1970 (b) Basra (Iraq), 1971
• epidemiological studies, e.g., (a) Seychelles
  (b) Faroe Islands (c) New Zealand

• Critical exposure pathway methylmercury from
  fish consumption

• Toxicity believed to be occurring at current
  exposures

• Widespread fish consumption advisories

• Methylmercury vs. Omega-III Fatty Acids

42
Herring
Salmon
Halibut
Swordfish
Shark
Tilefish
Tuna (fresh or frozen)
Oysters
Flounder or Sole
Pollock
Lobster
King Mackerel
Crabs
Shrimp
Red Snapper
Tuna
Grouper
Mahi Mahi
Clams
Catfish Scallops
Cod
Orange Roughy
canned, light
Graph based on data presented by the American
Heart Association -- http//www.americanheart.org
43
Source Gary Ginsberg, Connecticut Dept of Public
Health (2007). Risk-Benefit Synthesis for Fish
Consumption Advisories, presented at National
Forum on Fish Contaminants, Portland, ME.
http//www.epa.gov/waterscience/fish/forum/2007/pd
f/section2f.pdf
44
Public Health Context

• Methyl-mercury is a developmental neurotoxin --
  risks to fetuses/infants

• Cardiovascular toxicity might be even more
  significant (CRS, 2005)

• Uncertainties, but mercury toxicity relatively
  well understood
• well-documented tragedies (a) Minimata (Japan)
  1930 to 1970 (b) Basra (Iraq), 1971
• epidemiological studies, e.g., (a) Seychelles
  (b) Faroe Islands (c) New Zealand

• Critical exposure pathway methylmercury from
  fish consumption

• Toxicity believed to be occurring at current
  exposures

• Widespread fish consumption advisories

• Methylmercury vs. Omega-III Fatty Acids

Wildlife Health Issues e.g., fish-eating birds

• Selenium protective role?

45
Atmospheric Context
46

• Atmospheric deposition (both wet and dry) is an
  important loading pathway for mercury.
• For many ecosystems, it may be the largest
  contributor of new mercury.

47
Three forms of atmospheric mercury
48
Atmospheric Mercury Fate Processes
49
Atmospheric Chemical Reaction Scheme for Mercury
Reaction Rate Rate Units Reference
GAS PHASE REACTIONS GAS PHASE REACTIONS GAS PHASE REACTIONS GAS PHASE REACTIONS GAS PHASE REACTIONS
Hg0 O3 ? Hg(p) 3.0E-20 cm3/molec-sec cm3/molec-sec Hall (1995)
Hg0 HCl ? HgCl2 1.0E-19 cm3/molec-sec cm3/molec-sec Hall and Bloom (1993)
Hg0 H2O2 ? Hg(p) 8.5E-19 cm3/molec-sec cm3/molec-sec Tokos et al. (1998) (upper limit based on experiments)
Hg0 Cl2 ? HgCl2 4.0E-18 cm3/molec-sec cm3/molec-sec Calhoun and Prestbo (2001)
Hg0 OHC ? Hg(p) 8.7E-14 cm3/molec-sec cm3/molec-sec Sommar et al. (2001)
AQUEOUS PHASE REACTIONS AQUEOUS PHASE REACTIONS AQUEOUS PHASE REACTIONS AQUEOUS PHASE REACTIONS AQUEOUS PHASE REACTIONS
Hg0 O3 ? Hg2 4.7E7 (molar-sec)-1 (molar-sec)-1 Munthe (1992)
Hg0 OHC ? Hg2 2.0E9 (molar-sec)-1 (molar-sec)-1 Lin and Pehkonen(1997)
HgSO3 ? Hg0 Te((31.971T)-12595.0)/T) sec-1 T temperature (K) Te((31.971T)-12595.0)/T) sec-1 T temperature (K) Te((31.971T)-12595.0)/T) sec-1 T temperature (K) Van Loon et al. (2002)
Hg(II) HO2C ? Hg0 0 (molar-sec)-1 (molar-sec)-1 Gardfeldt Jonnson (2003)
Hg0 HOCl ? Hg2 2.1E6 (molar-sec)-1 (molar-sec)-1 Lin and Pehkonen(1998)
Hg0 OCl-1 ? Hg2 2.0E6 (molar-sec)-1 (molar-sec)-1 Lin and Pehkonen(1998)
Hg(II) ? Hg(II) (soot) 9.0E2 liters/gram t 1/hour liters/gram t 1/hour eqlbrm Seigneur et al. (1998) rate Bullock Brehme (2002).
Hg2 hlt ? Hg0 6.0E-7 (sec)-1 (maximum) (sec)-1 (maximum) Xiao et al. (1994) Bullock and Brehme (2002)
?
?
?
49
50
Why are emissions speciation data - and potential
plume transformations -- critical?
Logarithmic
NOTE distance results averaged over all
directions Some directions will have higher
fluxes, some will have lower
51
(No Transcript)
52
ARL's three long-term speciated atmospheric
mercury measurement sites
Canaan Valley
Beltsville
Grand Bay
Location of ARL's three long-term speciated
atmospheric mercury measurement sites, overlain
on a map of large mercury point sources (for
2002) in the United States and Canada based on
data from the U.S. EPA and Environment Canada.
53
Beltsville monitoring site
Brunner Island
Large Incinerators 3 medical waste, 1 MSW, 1
haz waste (Total Hg 500 kg/yr)
Harford County MSW Incin
Brandon Shores and H.A. Wagner
100 miles from DC
Montgomery County MSW Incin
Eddystone
Dickerson
Arlington - Pentagon MSW Incin
Possum Point
the region between the 20 km and 60 km radius
circles displayed around the monitoring site
might be considered the ideal location for
sources to be investigated by the site
Chalk Point
Morgantown
Bremo
54
Coal-fired power plants in MD, VA, PA, and DE
with the largest projected differences between
2010 base and 2010 Clean Air Interstate Rule
(CAIR) emissions
55
(No Transcript)
56
Atmospheric Mercury Measurement Site at
Beltsville, MD
ARLs speciated mercury measurements at
Beltsville are co-located with sites from several
monitoring networks (CASTNET, MDN, NADP-NTN) and
are funded by an Interagency Agreement between
the USEPA and NOAA
ARLs Winston Luke and Steve Brooks installing
ARLs first speciated mercury measurement
equipment at Beltsville in 2006
ARLs Steve Brooks, Paul Kelley Winston Luke
after installing first system at Beltsville in
2006
57
Atmospheric Mercury Measurement Site at
Beltsville, MD
Top of tower (close-up) with two sets of RGM and
Hg(p) collectors
ARLs Winston Luke working with RGM and Hg(p)
collectors
After RGM and Hg(p) is collected, it is desorbed
and analyzed inside the trailer, along with Hg(0)
Precipitation measurements (left to right)
Mercury Deposition Network, Major Ions
(e.g.acid rain), Precipitation Amount
mercury and trace gas monitoring tower (10 meters)
58
Elemental Hg0
59
(a few peaks gt 500 pg m-3 not shown)
Hg-P
60
RGM
RGM concentrations generally lt 20 pg m-3, with
more frequent peaks in concentration than was
seen for Hg-P
61
Sometimes, we see evidence of local and regional
plume impacts
Beltsville Episode January 7, 2007
62
Sometimes, we see evidence of local and regional
plume impacts
63
Sometimes, we see evidence of local and regional
plume impacts

• Although sometimes we see elevated
• RGM due to other factors
• oxidation of elemental mercury to form RGM
• (elemental mercury may be from global
  background)
• atmospheric mixing processes
• (e.g., parcels of air from higher altitudes mix
  down to the ground)

Without atmospheric models, it is difficult to
unravel the reasons for the mercury
concentrations deposition that we observe
64
Measurements can tell us concentrations and
deposition at a given location... But,
measurements cant tell us everything we want to
know
We also need

• Concentrations deposition in the surrounding
  region
• -- there might be large spatial gradients
• -- want information for an entire ecosystem

• Source attribution and other explanatory
  information
• -- where is the mercury coming from?
• -- why are we seeing what we are seeing?

• Impacts of potential future emissions scenarios
• -- due to alternative domestic regulatory
  actions
• -- due to possible international developments

65
HYSPLIT Atmospheric Model Hybrid Single Particle
Lagrangian Integrated Trajectory

• developed by Roland Draxler and colleagues at ARL
• many enhancements since start in 1979
• available on the ARL-READY website Glenn Rolph
• uses NOAA met data (and others)
• used at NOAA and around the world
• trajectories and dispersion (3-D)
• many applications, e.g., emergency response
• has been adapted to simulate atmospheric mercury

66
NOAA HYSPLIT MODEL
67
(No Transcript)
68
deposition (ug/m2)
Beltsville monitoring site
100 - 1000 10 100 1 - 10 0.1 1
Washington D.C.
Howard University
Model-predicted hourly mercury deposition (wet
dry) in the vicinity of one example Hg source for
a 3-day period in July 2007
one Hg emissions source
hourly deposition converted to annual
equivalent
69
deposition (ug/m2)
Beltsville monitoring site
100 - 1000 10 100 1 - 10 0.1 1
Washington D.C.
Howard University
Model-predicted hourly mercury deposition (wet
dry) in the vicinity of one example Hg source for
a 3-day period in July 2007
one Hg emissions source
hourly deposition converted to annual
equivalent
70
Large, time-varying spatial gradients in
deposition source-receptor relationships
deposition (ug/m2)
Beltsville monitoring site
100 - 1000 10 100 1 - 10 0.1 1
Washington D.C.
Howard University
Model-predicted hourly mercury deposition (wet
dry) in the vicinity of one example Hg source for
a 3-day period in July 2007
one Hg emissions source
hourly deposition converted to annual
equivalent
71
2002 U.S. and Canadian Emissions of Total
Mercury Hg(0) Hg(p) RGM
There are a lot of sources!
Note some large Canadian point sources may
not be included due to secrecy agreements between
industry and the Canadian government.
72
Emissions History and Regulatory Context
73
Some events in the U.S. regulation and prevention
of mercury emissions
1965
1970
1975
1970s - 1990s many mercury-cell chlor-alkali
plants converted to alternate processes or closed
due to regulatory and other pressures
1980
1985
1990
1995
2000
Mercury-Cell Chlor-Alkali Plant, producing
chlorine sodium hydroxide (caustic soda) using
large amounts of mercury in the process
2005
2010
74
Marvin et al. (2004). Environmental Research 95,
351362.
75
Trends in Herring Gull Egg Hg concentrations in
the Great Lakes Region
Total mercury concentrations in eggs from
colonies in the Great Lakes region, expressed in
units of ug Hg/g (wet weight). Source of
data Canadian Wildlife Service
76
Some events in the U.S. regulation and prevention
of mercury emissions
1965
1970
1975
1970s - 1990s many mercury-cell chlor-alkali
plants converted to alternate processes or closed
due to regulatory and other pressures
1980
1985
Clean Air Act Amendments of 1990 calls for
Maximum Achievable Control Technology (MACT) to
regulate hazardous air pollutants intent is to
prohibit emissions trading for these air toxics
1990

• 1990s Hg emissions from municipal and medical
  waste incinerators fall dramatically due to
• closure of some municipal waste incinerators and
  many medical waste incinerators
• MACT-related pollution control requirements
• reduction in mercury content of waste (e.g.,
  battery legislation)

1995
2000
2005
2010
77
Mercury emissions from municipal and medical
waste incineration in the United States dropped
significantly during the 1990s

• REASONS
• closure of some municipal waste incinerators and
  many medical waste incinerators
• MACT-related pollution control requirements
• reduction in mercury content of waste (e.g.,
  battery legislation)

78
Direct, Anthropogenic Mercury Emissions in the
United States
(data from USEPA)
79
Some events in the U.S. regulation and prevention
of mercury emissions
1965
1970
1975
1970s - 1990s many mercury-cell chlor-alkali
plants converted to alternate processes or closed
due to regulatory and other pressures
1980
1985
Clean Air Act Amendments of 1990 calls for
Maximum Achievable Control Technology (MACT) to
regulate hazardous air pollutants intent is to
prohibit emissions trading for these air toxics
1990

• 1990s Hg emissions from municipal and medical
  waste incinerators fall dramatically due to
• closure of some municipal waste incinerators and
  many medical waste incinerators
• MACT-related pollution control requirements
• reduction in mercury content of waste (e.g.,
  battery legislation)

1995
2002 Clear Skies Initiative for power plants
introduced (ultimately withdrawn)
2000
2005 CAIR (Clean Air Interstate Rule) for power
plants (Hg reduced as co-benefit of SO2 NOx
controls)
2005 EPA meets court-ordered deadline and
promulgates CAMR (Clean Air Mercury Rule) for
power plants based on Hg emissions trading
2005
Hot Spot Controversy -- Many States sue EPA
propose / promulgate more strict regulations
2010
80
NOAA Report to Congress on Mercury Contamination
in the Great Lakes
http//www.arl.noaa.gov/data/web/reports/cohen/NOA
A_GL_Hg.pdf

• The Conference Report accompanying the
  consolidated Appropriations Act, 2005 (H. Rpt.
  108-792) requested that NOAA, in consultation
  with the EPA, report to Congress on mercury
  contamination in the Great Lakes, with trend and
  source analysis.
• Reviewed by NOAA, EPA, DOC, White House Office of
  Science and Technology Policy, and Office of
  Management and Budget (OMB).
• Review process took 2 years.
• Transmitted to Congress on
• May 14, 2007

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81
81
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Figure 44. Largest modeled contributors to Lake
Michigan (close-up). (same legend as previous
slide)
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Top 25 modeled sources of atmospheric mercury to
Lake Michigan (based on 1999 anthropogenic
emissions in the U.S. and Canada)
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Emissions and deposition to Lake Michigan
arising from different distance ranges (based
on 1999 anthropogenic emissions in the U.S. and
Canada)
but these local emissions are responsible for
a large fraction of the modeled atmospheric
deposition
Only a small fraction of U.S. and Canadian
emissions are emitted within 100 km of Lake
Michigan
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Some events in the U.S. regulation and prevention
of mercury emissions
1965
1970
1975
1970s - 1990s many mercury-cell chlor-alkali
plants converted to alternate processes or closed
due to regulatory and other pressures
1980
1985
Clean Air Act Amendments of 1990 calls for
Maximum Achievable Control Technology (MACT) to
regulate hazardous air pollutants intent is to
prohibit emissions trading for these air toxics
1990

• 1990s Hg emissions from municipal and medical
  waste incinerators fall dramatically due to
• closure of some municipal waste incinerators and
  many medical waste incinerators
• MACT-related pollution control requirements
• reduction in mercury content of waste (e.g.,
  battery legislation)

1995
2002 Clear Skies Initiative for power plants
introduced (ultimately withdrawn)
2000
2005 CAIR (Clean Air Interstate Rule) for power
plants (Hg reduced as co-benefit of SO2 NOx
controls)
2005 EPA meets court-ordered deadline and
promulgates CAMR (Clean Air Mercury Rule) for
power plants based on Hg emissions trading
2005
Hot Spot Controversy -- Many States sue EPA
propose / promulgate more strict regulations
2010
2008 CAMR and CAIR overturned... What is next?
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Thanks!
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