Transcript – Mercury in the Environment
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
[email protected]
http://www.arl.noaa.gov/ss/transport/cohen.html
Howard University Department of Chemistry Seminar October 24, 2008, Washington D.C.
atmospheric deposition to the watershed adapted from slides prepared by USEPA and NOAA Mercury transformed by bacteria into methylmercury in sediments, soils & water, then bioaccumulates in fish 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
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:
o o
transported throughout the environment chemical transformations interconvert different mercury species
This has always been going on, ... always has been Hg in fish
Pre-Industrial Global Mercury Cycling
Sunderland and Mason (2007). Global Biogeochemical Cycles 21, 4022
GLOBAL MERCURY CYCLING
20
10 6 moles per year
10 0 -10
natural extraction from deep reservoirs, e.g., volcanoes natural evasion from land natural evasion from ocean
-20 (note -10 6 moles ~ 200 metric tons)
natural dep to land natural dep to ocean
pre-industrial:
total mercury in atmosphere ~ 8.0 x 10 6 moles
Based on data presented in Sunderland and Mason (2007) Global Biogeochemical Cycles 21 : GB4022
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
GLOBAL MERCURY CYCLING
20
10 6 moles per year
10 0 -10
natural extraction from deep reservoirs, e.g., volcanoes natural evasion from land natural evasion from ocean
-20 (note -10 6 moles ~ 200 metric tons)
natural dep to land natural dep to ocean
pre-industrial:
total mercury in atmosphere ~ 8.0 x 10 6 moles
Based on data presented in Sunderland and Mason (2007) Global Biogeochemical Cycles 21 : GB4022
10 6 moles per year
20 10
anthrop direct emit anthrop re-emit from land anthrop re-emit from ocean
0 -10
contemporary:
total mercury in atmosphere ~ 28.0 x 10 6 moles
-20
anthrop dep to land anthrop dep to ocean
Natural vs. anthropogenic mercury?
Studies show that anthropogenic activities have typically increased bioavailable Hg concentrations in ecosystems by a factor of 2 – 10
Freemont Glacier, Wyoming
source: USGS, Shuster et al., 2002
What Influences Hg Levels in Fish?
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 waterbody’s 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
What Influences Hg Levels in Fish?
Current / past atmospheric and other Hg inputs to the fish’s ecosystem
Evers, D.
et al
(2007). Biological Mercury Hotspots in the Northeastern United States and Southeastern Canada. BioScience 57 , 29-43.
Evers, D.
et al
(2007). Biological Mercury Hotspots in the Northeastern United States and Southeastern Canada. BioScience 57 , 29-43.
What Influences Hg Levels in Fish?
Current / past atmospheric and other Hg inputs to the fish’s ecosystem
Biogeochemical factors influencing the degree of mercury methylation in the ecosystem (sulfate, dissolved organic carbon, pH, etc)
Mercury Sensitivity Map for Aquatic Ecosystems in the Contiguous 48 United States
from Myers et al.
(2007) Science Metrics Used to Create Map: Water Chemistry pH, DOC, Sulfate, ANC, Total Hg, MeHg Others Hydric Soils, Hg Deposition
What Influences Hg Levels in Fish?
Current / past atmospheric and other Hg inputs to the fish’s 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
Mercury Bioconcentration
Figure from Charley Driscoll, Syracuse University
What Influences Hg Levels in Fish?
Current / past atmospheric and other Hg inputs to the fish’s 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
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)
What Influences Hg Levels in Fish?
Current / past atmospheric and other Hg inputs to the fish’s 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
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
What Influences Hg Levels in Fish?
Current / past atmospheric and other Hg inputs to the fish’s 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:
o
freshwater (inland) fish -- LARGE UNCERTAINTIES
o
estuarine & marine fish -- VERY LARGE UNCERTAINTIES
Link Between Seawater Hg and Tuna Hg Concentrations?
2.5
2
Mediterranean Sea raw data 5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Mediterranean Sea Atlantic Ocean Pacific Ocean
(seawater data assembled by Sunderland and Mason, 2007) 1.5
1
Atlantic Ocean published regression for Hg vs. weight for two different areas
0.5
Pacific Ocean Pacific NW regression Hawaii raw data
0 0 5 10 15 20 Tuna Weight (kg) 25 30 Tuna Hg data assembled by Elsie Sunderland from the following sources: http://www.atuna.com
, Brooks, 2004 (Hawaii); Storelli et al., 2002 (Ionian Sea); Storelli & Marcotrigiano, 2004 (Adriatic Sea); Morrisey et al., 2004 (Pacific NW, USA). Atlantic: Anderson and Depledge, (1997).
What Are Hg Levels in Fish?
State Monitoring Programs
o
Each state’s program is different
o o o
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
Spatial Variation of Mercury in Fish (Standardized)
Slide from Steve Wente, USGS
NIEHS
Mercury (ppm) > 1.5
1.2 – 1.5
0.9 – 1.2
0.6 – 0.9
0.3 – 0.6
< 0.3
What Are Hg Levels in Fish?
State Monitoring Programs
o
Each state’s program is different
o o o
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
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0.00
4.5
3.7
3.2
Mercury Levels in Commercial Fish and Shellfish 2.2
“error bars” show range of mercury concentrations for a given species
Number of Samples
x 300 - 700 100 - 300 50 - 100 10 - 50 1 - 10
Fish concentration data from NOAA and FDA. Downloaded Sept 2008 from the EPA-FDA fish-mercury website:
http://www.cfsan.fda.gov/~frf/sea-mehg.html
What Are Hg Levels in Fish?
State Monitoring Programs
o
Each state’s program is different
o o o
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
Public Health Context
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
o
epidemiological studies, e.g., (a) Seychelles; (b) Faroe Islands; (c) New Zealand
o
well-documented tragedies: Minimata (Japan) ~1930 to ~1970 Basra (Iraq), 1971
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
o
well-documented tragedies: (a) Minimata (Japan) ~1930 to ~1970; (b) Basra (Iraq), 1971
o
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 can’t easily avoid it (PCB’s, Dioxins and other hydrophobic contaminants concentrated in fat)
Mean Methylmercury Concentrations for "Top 24" Types of Fish Consumed in U.S. Commercial Seafood Market
1.2
1 0.8
0.6
0.4
0.2
0 S wo rdfi sh Lo S bs har ter k A me ric an Hal ibu t S abl e f is h Roc kfi sh Tun a-c ann ed Cr ab s Dung en es s P ol lo Cr ck ab s S now Cr ab s Lo B bs lue ter S pi ne y Cod Fl atf is Cr h ab s P K ing er ch-O cea n S hr imp S al mo n O ys ter s Cr awfi sh Catfi sh S cal lop s S ar di ne s Cl ams
Fish Type
Source of data:
Carrington and Bolger, 2002
Based on slide from:
Elsie Sunderland, USEPA
Percent Contribution to per capita Methylmercury Intake by Fish Type for "Top 24" Types of Fish in U.S. Commercial Seafood Market
40% 35% 30% 25% 20% 15% 10% 5% 0% Tun a-c ann ed Po llo ck Sh rimp Cod Hal ibu t Swo rdfi sh Sa lmo n Catfi sh Lo bs ter Ame ric Cr an ab s Bl ue Fl atf is h Roc kfi sh Sh Cr ar k ab s Sn ow O Lo ys bs ter s ter Spi ne y Sc al lop s Cl ams Cr ab s Dung en es s Sa bl e f is h Sa rdi Pe ne rc s h-O cea Cr n ab s Ki ng Cr awfi sh
Fish Type
† Estimate based on the product of per capita fish consumption rates and mean methylmercury concentrations of each type of fish (Carrington and Bolger, 2003)
Source of data:
Carrington and Bolger, 2002
Based on slide from:
Elsie Sunderland, USEPA
Blood Hg (ug/L) - U.S. Women ages 6-49 based on NHANES data (1999-2002)
Mean Organic [Hg] μg/L (95% CI) 2.7 (2.4-3.1) Atlantic Coast 1.7 (1.5-1.9) Pacific Coast 1.4 (0.7-2.0) Northeast 1.3 (0.6-2.0) Gulf Coast 1.1 (0.7-1.6) South 1.0 (0.7-1.2) West 0.8 (0.6-1.0) Mid West
Source of data:
Mahaffey et al., 2005
Based on slide from:
Elsie Sunderland, USEPA
60 50 40 30 20 10 0 70
Total Mercury Levels in Women,
Aged 16-49
by Weekly Fish Consumption Levels
2+/WK < 2/WK <1 1 to 4 5 to 9 10 to 14
Mercury Levels (ug/L)
>/= 15 Slide from Kate Mahaffey
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
o
well-documented tragedies: (a) Minimata (Japan) ~1930 to ~1970; (b) Basra (Iraq), 1971
o
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
Based on the NHANES national survey, approximately 6% of women of child-bearing age in the U.S. have blood mercury levels above the EPA’s 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, 1999 –2002.
Morbidity and Mortality Weekly Report
(CDC).
53
(43):1018 –1020.
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 McKelvey, W., et al. (2007). A Biomonitoring Study of Lead, Cadmium, and Mercury in the Blood of New York City Adults. Environ Health Perspect 115 :1435 –1441.
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
o
well-documented tragedies: (a) Minimata (Japan) ~1930 to ~1970; (b) Basra (Iraq), 1971
o
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
Mercury Fish Consumption Advisories are Ubiquitous
March 2004
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.
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
o
well-documented tragedies: (a) Minimata (Japan) ~1930 to ~1970; (b) Basra (Iraq), 1971
o
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
2.5
2.0
Herring
1.5
Salmon
1.0
Halibut Swordfish Shark Oysters
0.5
Flounder or Sole Pollock Crabs Lobster Shrimp Clams Catfish
0.0
Scallops Tuna* Mahi Cod Mahi
0.0
0.2
* canned, light Tuna (fresh or frozen)
0.4
Grouper King Mackerel Red Snapper Orange Roughy
0.6
0.8
1.0
Mercury Concentration
(parts per million) 1.2
Tilefish
1.4
1.6
Graph based on data presented by the American Heart Association -- http://www.americanheart.org
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/pdf/section2f.pdf
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
o
well-documented tragedies: (a) Minimata (Japan) ~1930 to ~1970; (b) Basra (Iraq), 1971
o
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
Selenium – protective role?
+ Wildlife Health Issues
e.g., fish-eating birds
Atmospheric Context
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.
atmospheric deposition to the watershed atmospheric deposition to the water surface
Three “forms” of atmospheric mercury
Elemental Mercury: Hg(0)
•
~ 95% of total Hg in atmosphere
• •
not very water soluble long atmospheric lifetime (~ 0.5 - 1 yr); globally distributed Reactive Gaseous Mercury (“RGM”)
•
a few percent of total Hg in atmosphere
•
oxidized mercury: Hg(II)
• •
HgCl2, others species?
somewhat operationally defined by measurement method
• • •
very water soluble short atmospheric lifetime (~ 1 week or less); more local and regional effects Particulate Mercury (Hg(p)
•
a few percent of total Hg in atmosphere
•
not pure particles of mercury… (Hg compounds associated with atmospheric particulate)
• • • •
species largely unknown (in some cases, may be HgO?) moderate atmospheric lifetime (perhaps 1~ 2 weeks) local and regional effects bioavailability?
Atmospheric Mercury Fate Processes
Upper atmospheric halogen-mediated heterogeneous oxidation?
Polar sunrise “mercury depletion events”
Br
cloud
Elemental Mercury [Hg(0)] Hg(II), ionic mercury, RGM Particulate Mercury [Hg(p)]
CLOUD DROPLET
Vapor phase: Hg(0) oxidized to RGM and Hg(p) by O 3 , H 2 0 2 , Cl 2 , OH, HCl
Primary Anthropogenic Emissions Natural emissions Hg(p)
Hg(II)
reduced
to Hg(0) by SO 2 and sunlight
Adsorption/ desorption of Hg(II) to /from soot
Hg(0)
oxidized
to dissolved Hg(II) species by O 3 , OH, HOCl, OCl -
Multi-media interface
Wet deposition Re-emission of previously deposited anthropogenic and natural mercury Dry deposition
?
Atmospheric Chemical Reaction Scheme for Mercury
Reaction Rate
GAS PHASE REACTIONS
Hg 0 Hg 0 Hg 0 + O 3
Hg(p) + HCl
HgCl 2 + H 2 O 2
Hg(p)
3.0E-20 1.0E-19 8.5E-19
Units
cm 3 /molec-sec cm 3 /molec-sec cm 3 /molec-sec
Reference
Hall (1995) Hall and Bloom (1993) Tokos et al. (1998) (upper limit based on experiments) Calhoun and Prestbo (2001) Sommar et al. (2001)
?
?
Hg 0 + Cl 2
HgCl 2 Hg 0 +OH
C
Hg(p)
4.0E-18 8.7E-14 cm 3 /molec-sec cm 3 /molec-sec
AQUEOUS PHASE REACTIONS
Hg 0 + O 3
Hg +2 Hg 0 + OH
C
Hg +2 HgSO 3
Hg 0
4.7E+7 2.0E+9 (molar-sec) -1 (molar-sec) -1 T*e ((31.971*T)-12595.0)/T) sec -1 [T = temperature (K)]
Hg(II) + HO 2
C
Hg 0 Hg 0 + HOCl
Hg +2 Hg 0 + OCl -1
Hg +2 Hg(II)
Hg(II) (soot)
~ 0 2.1E+6 2.0E+6 9.0E+2 (molar-sec) -1 (molar-sec) -1 (molar-sec) -1 liters/gram; t = 1/hour
Hg +2 + h
<
Hg 0
6.0E-7 (sec) -1 (maximum) Munthe (1992) Lin and Pehkonen(1997) Van Loon et al. (2002) Gardfeldt & Jonnson (2003) Lin and Pehkonen(1998) Lin and Pehkonen(1998) eqlbrm: Seigneur et al. (1998) rate: Bullock & Brehme (2002).
Xiao et al. (1994); Bullock and Brehme (2002)
4 9
Why are emissions speciation data - and potential plume transformations -- critical?
100 10 Hg(II) emit Hg(p) emit Hg(0) emit 1 0.1
0.01
0.001
0 - 15 15 - 30 30 - 60 60 - 120 distance range from source (km) 120 - 250
Logarithmic
NOTE: distance results averaged over all directions – Some directions will have higher fluxes, some will have lower
Hg from other sources: local, regional & more distant emissions of Hg(0), Hg(II), Hg(p) atmospheric deposition to the water surface atmospheric deposition to the watershed Measurement of wet deposition Measurement of ambient air concentrations
• • •
Atmospheric measurements are needed to:
estimate deposition and trends improve understanding of key processes evaluate / improve models
ARL's three long-term speciated atmospheric mercury measurement sites
Canaan Valley Beltsville
Large Point Sources of Mercury Emissions Based on the 2002 EPA NEI and 2002 Envr Canada NPRI
size/shape of symbol denotes amount of mercury emitted (kg/yr) 5 10 50 100 – 300 10 50 100 300 500 500 - 1000 1000 - 3000 Grand Bay color of symbol denotes type of mercury source
coal-fired power plants other fuel combustion waste incineration metallurgical manufacturing & other 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.
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 Montgomery County MSW Incin Dickerson 100 miles from DC Arlington - Pentagon MSW Incin Eddystone 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
Bremo Morgantown Chalk Point Monitoring sites
rural AQS other AQS NADP/MDN CASTNet Hg site IMPROVE
Symbol color indicates type of mercury source
coal incinerator metals manuf/other
Symbol size and shape indicates 1999 mercury emissions, kg/yr
1 - 50 50 - 100 100 - 200 200 – 400 400 - 700 700 – 1000 > 1000
Coal-fired power plants in MD, VA, PA, and DE with the largest projected differences between Beltsville monitoring 2010 base and 2010 Clean Air site Interstate Rule (CAIR) emissions Brandon Shores
coal-fired power plants in MD, VA, PA, and DE with largest differences between 2010 base and 2010 CAIR projected emissions
Brandon Shores
600
Morgantown Chalk Point
500
Morgantown
400
Chalk Point
300
Dickerson H.A. Wagner
200
H g(0) H g(2) H g(p)
100 0
Patuxent River Howard University Atmos. Site ( + NASA, NSF, NOAA, others) Patuxent Wildlife Research Center (USGS) Patuxent Research Refuge (FWS) Beltsville Agricultural Research Center (USDA) 5 km Beltsville Atmospheric Monitoring Site (EPA, NOAA, State of MD, Univ. of MD)
Atmospheric Mercury Measurement Site at Beltsville, MD
ARL’s 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 ARL’s Winston Luke and Steve Brooks installing ARL’s first speciated mercury measurement equipment at Beltsville in 2006 ARL’s Steve Brooks, Paul Kelley & Winston Luke after installing first system at Beltsville in 2006
Atmospheric Mercury Measurement Site at Beltsville, MD
Top of tower (close-up) with two sets of RGM and Hg(p) collectors ARL’s Winston Luke working with RGM and Hg(p) collectors
Precipitation measurements (left to right): Mercury Deposition Network, Major Ions (e.g.”acid rain”), Precipitation Amount
mercury and trace gas monitoring tower (10 meters)
After RGM and Hg(p) is collected, it is desorbed and analyzed inside the trailer, along with Hg(0)
Beltsville Time Series 5 4.5
4
Sytem 1 System 2 System 3
Elemental Hg0
3.5
3 2.5
2 1.5
1 0.5
Nov Dec Jan Feb Mar Apr May Jun Jul Aug 0 2006.83 2006.92 2007.00 2007.08 2007.17 2007.25 2007.33 2007.42 2007.50 2007.58 2007.67
Decimal Year
Beltsville Time Series 240 220 200 180 (a few peaks > 500 pg m-3 not shown)
Sytem 1 System 2 System 3
Hg-P
160 140 120 100 80 60 40 20 0 Nov Dec Jan Feb Mar Apr May Jun Jul Aug -20 2006.83 2006.92
2007 2007.08 2007.17 2007.25 2007.33 2007.42 2007.5 2007.58 2007.67
Decimal Year
Beltsville Time Series 260 240 220 200 180 160 140 120 100 80 60
Sytem 1 System 2 System 3
RGM
40 20 0 Nov Dec Jan Feb Mar Apr May Jun Jul Aug -20 2006.86 2006.95 2007.03 2007.11 2007.20 2007.28 2007.36 2007.45 2007.53 2007.61
Decimal Year
RGM concentrations generally < 20 pg m
-3
, with more frequent peaks in concentration than was seen for Hg-P
Sometimes, we see evidence of local and regional “plume” impacts
Beltsville Episode January 7, 2007
100 80 60 40 20 0 January 7, 2007 (Eastern Standard Time)
Sometimes, we see evidence of local and regional “plume” impacts
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
Measurements can tell us concentrations and deposition at a given location...
But, measurements can’t tell us everything we want to know Atmospheric mercury fate and transport models are needed to obtain these types of information
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
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
NOAA HYSPLIT MODEL Lagrangian Puff Atmospheric Fate and Transport Model TIME (hours) 0 1 2
= mass of pollutant (changes due to chemical transformations and deposition that occur at each time step) The puff’s mass, size, and location are continuously tracked… Phase partitioning and chemical transformations of pollutants within the puff are estimated at each time step Initial puff location is at source, with mass depending on emissions rate Centerline of puff motion determined by wind direction and velocity Dry and wet deposition of the pollutants in the puff are estimated at each time step.
deposition 1 deposition 2 deposition to receptor lake
Beltsville monitoring site
Washington D.C.
Howard University
one Hg emissions source
deposition (ug/m2)* 100 - 1000 10 – 100 1 - 10 0.1 – 1
Model-predicted hourly mercury deposition (wet + dry) in the vicinity of one example Hg source for a 3-day period in July 2007
* hourly deposition converted to annual equivalent
Beltsville monitoring site
Washington D.C.
Howard University
one Hg emissions source
deposition (ug/m2)* 100 - 1000 10 – 100 1 - 10 0.1 – 1
Model-predicted hourly mercury deposition (wet + dry) in the vicinity of one example Hg source for a 3-day period in July 2007
* hourly deposition converted to annual equivalent
Large, time-varying spatial gradients in deposition & source-receptor relationships
Beltsville monitoring site
deposition (ug/m2)* 100 - 1000 10 – 100 1 - 10 0.1 – 1 Washington D.C.
Howard University
one Hg emissions source Model-predicted hourly mercury deposition (wet + dry) in the vicinity of one example Hg source for a 3-day period in July 2007
* hourly deposition converted to annual equivalent
2002 U.S. and Canadian Emissions of Total Mercury [Hg(0) + Hg(p) + RGM]
There are a lot of sources!
Large Point Sources of Mercury Emissions Based on the 2002 EPA NEI and 2002 Envr Canada NPRI*
size/shape of symbol denotes amount of mercury emitted (kg/yr) 5 10 50 100 – 300 10 50 100 300 500 500 - 1000 1000 - 3000 color of symbol denotes type of mercury source
coal-fired power plants other fuel combustion waste incineration metallurgical manufacturing & other
* Note – some large Canadian point sources may not be included due to secrecy agreements between industry and the Canadian government.
Emissions History and Regulatory Context
1985 1990 1995 2000 2005 2010 1965 1970 1975 1980 Some events in the U.S. regulation and prevention of mercury emissions 1970’s - 1990’s: many mercury-cell chlor-alkali plants converted to alternate processes or closed due to regulatory and other pressures
Mercury-Cell Chlor-Alkali Plant, producing chlorine & sodium hydroxide (caustic soda) using large amounts of mercury in the process
Marvin
et al
. (2004). Environmental Research 95 , 351 –362.
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
0.8
0.6
0.4
0.2
0.0
1970 1. Granite Island 1980 0.8
1990 2000 2. Agawa Rock 0.6
0.4
0.2
0.0
1970 1980 1990
1
0.8
0.6
0.4
0.2
0.0
1970 3. Big Sister Island 1980 1990 0.8
0.6
0.4
0.2
0.0
1970 4. Gull Island 1980 2000 1990 2000
3
2000
Superior Mi h c igan
4 2
0.8
0.6
0.4
0.2
0.0
1970 6. Double Island 1980 1990 0.8
0.6
0.4
0.2
0.0
1970
6 5
7. Chantry Island
8 9
0.8
0.6
0.4
0.2
0.0
1970 5. Channel Shelter Island 1980 1990 2000 0.8
0.6
0.4
0.2
0.0
1970 8. Fighting Island 1980 1990 1980 2000 1990 2000 0.8
0.6
0.4
0.2
0.0
1970 15. Strachan Island 1980 1990 1.2
1.0
0.8
0.6
0.4
0.2
0.0
1970 14. Snake Island 1980 1990 2000 2000
15 14
Huron
7
2000
13 12
Ontario
11 10
Erie
1.0
0.8
0.6
0.4
0.2
0.0
1970 13. Toronto Harbour 1980 1990 0.8
0.6
0.4
0.2
0.0
1970 11. Niagara River 1980 1990 2000 0.8
0.6
0.4
0.2
0.0
1970 12. Hamilton Harbour 1980 1990 2000 0.8
0.6
0.4
0.2
0.0
1970 9. Middle Island 1980 1990 2000 0.8
0.6
0.4
0.2
0.0
1970 10. Port Colborne 1980 1990 2000 2000
1985 1990 1995 2000 2005 2010 1965 1970 1975 1980 Some events in the U.S. regulation and prevention of mercury emissions 1970’s - 1990’s: many mercury-cell chlor-alkali plants converted to alternate processes or closed due to regulatory and other pressures 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’s – 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)
Mercury emissions from municipal and medical waste incineration in the United States dropped significantly during the 1990’s 120 100 80 60 40 20 0 1990
hazardous waste incinerators medical waste incinerators municipal waste incinerators
REASONS:
o closure of some municipal waste incinerators and many medical waste incinerators o MACT-related pollution control requirements o reduction in mercury content of waste (e.g., battery legislation)
1995 2000
Direct, Anthropogenic Mercury Emissions in the United States
(data from USEPA) 250 200 150 100 50 Other categories* Gold mining Hazardous waste incineration Electric Arc Furnaces ** Mercury Cell Chlor-Alkali Plants Industrial, commercial, institutional boilers and process heaters Municipal waste combustors Medical waste incinerators Utility coal boilers 0 1990 1999
* Data for Lime Manufacturing are not available for 1990.
** Data for Electric Arc Furnaces are not available for 1999. The 2002 estimate (10.5 tons) is shown here.
1985 1990 1995 2000 2005 2010 1965 1970 1975 1980 Some events in the U.S. regulation and prevention of mercury emissions 1970’s - 1990’s: many mercury-cell chlor-alkali plants converted to alternate processes or closed due to regulatory and other pressures 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’s – 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) 2002 – Clear Skies Initiative for power plants introduced (ultimately withdrawn) 2005 – CAIR (Clean Air Interstate Rule) for power plants (Hg reduced as co-benefit of SO 2 & NO x controls) 2005 – EPA meets court-ordered deadline and promulgates CAMR (Clean Air Mercury Rule) for power plants – based on Hg emissions trading “Hot Spot” Controversy -- Many States sue EPA & propose / promulgate more strict regulations
NOAA Report to Congress on Mercury Contamination in the Great Lakes http://www.arl.noaa.gov/data/web/reports/cohen/NOAA_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
80
81
Figure 44. Largest modeled contributors to Lake Michigan (close-up).
(same legend as previous slide)
82
Top 25 modeled sources of atmospheric mercury to Lake Michigan (based on 1999 anthropogenic emissions in the U.S. and Canada)
25 20 15 10 5
IN Parkview Mem. Hosp.
TX Monticello MI IL Monroe Power Plant VULCAN MCCOOK LIME WI Edgewater IN State Line IL Fisk IN IL BALL MEMORIAL Marblehead Lime (South Chicago) IN Rockport IL Joliet 9 IN R.M. Schahfer IL Crawford IN WI CLARIAN HEALTH Superior Special Services IL Powerton WI South Oak Creek KY LWD NV JERRITT CANYON IL Will County IL MARBLEHEAD LIME CO.
IL Waukegan MI J.H. Campbell IL Joliet 29 WI Pleasant Prairie coal-fired elec gen other fuel combustion waste incineration metallurgical manufacturing/other
0 0% 20% 40% 60% 80%
Cumulative Fraction of Hg Deposition
83
Emissions and deposition to Lake Michigan arising from different distance ranges
(based on 1999 anthropogenic emissions in the U.S. and Canada) 50 5 40 30 … but these “local” emissions are responsible for a large fraction of the modeled atmospheric deposition Emissions Deposition Flux 20 10 0 0 - 100 100 - 200 200 - 400 400 - 700 700 - 1000 1000 - 1500 1500 - 2000 2000 - 2500 Distance Range from Lake Michigan (km) > 2500 Only a small fraction of U.S. and Canadian emissions are emitted within 100 km of Lake Michigan… 0 2 1 4 3 84
1985 1990 1995 2000 2005 2010 1965 1970 1975 1980 Some events in the U.S. regulation and prevention of mercury emissions 1970’s - 1990’s: many mercury-cell chlor-alkali plants converted to alternate processes or closed due to regulatory and other pressures 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’s – 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) 2002 – Clear Skies Initiative for power plants introduced (ultimately withdrawn) 2005 – CAIR (Clean Air Interstate Rule) for power plants (Hg reduced as co-benefit of SO 2 & NO x controls) 2005 – EPA meets court-ordered deadline and promulgates CAMR (Clean Air Mercury Rule) for power plants – based on Hg emissions trading “Hot Spot” Controversy -- Many States sue EPA & propose / promulgate more strict regulations 2008 – CAMR and CAIR overturned... What is next?