Summary of Part B: Mercury Nicola Pirrone CNR Institute of - - PowerPoint PPT Presentation

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Summary of Part B: Mercury

Nicola Pirrone

CNR – Institute of Atmospheric Pollution Research Rome, Italy

6th Meeting of the TF HTAP Mercure Brussels Center Louise, Brussels 14-16 June 2010

B1 - Conceptual Overview (30 pages)

Lead Author: Robert Mason Contributing Authors: Ian Hedgecock, Nicola Pirrone, Noriyuki Suzuki, Leonard Levin

B2 – Observations (57 pages)

Lead Author: Ralf Ebinghaus Contributing Authors: Aurélien Dommergue, Dan Jaffe, Gerald J. Keeler, Hans Herbert Kock, Nicola Pirrone, David Schmeltz, Francesca Sprovieri

B3 – Emissions (24 pages)

Lead Author: Nicola Pirrone Contributing Authors: Sergio Cinnirella, Xinbin Feng, Hans Friedli, Leonard Levin, Jozef Pacyna, Elisabeth G. Pacyna, David Streets, Kyrre Sundseth

B4 - Global and Regional Modeling (50 pages)

Lead Authors: Oleg Travnikov, Che-Jen Lin, Ashu Dastoor Contributing Authors: O. Russell Bullock, Ian M. Hedgecock, Christopher Holmes, Ilia Ilyin, Lyatt Jaeglé, Gerlinde Jung, Li Pan, Pruek Pongprueksa, Christian Seigneur, Henrik Skov

B5 – Impacts (39 pages)

Lead Author: Elsie Sunderland Contributing Authors: Elizabeth Corbitt, Daniel Cossa, David Evers, Hans Friedli, David Krabbenhoft, Leonard Levin, Nicola Pirrone, Glenn Rice

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

B6 – Executive Summary (10 pages)

Authors: Nicola Pirrone, Ian M. Hedgecock

Part B = 210 pages

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Wet Deposition and Dry Deposition of Gaseous and Particulate Hg

Bioaccumulation

• f CH3Hg

Watershed Retention and Transport/Runoff of Hg and CH3Hg Evasion from Soil and Vegetation Evasion

A: Major Ecosystem Inputs and Outputs of Mercury B: Major Aquatic Mercury Pathways

Hg(II)

methylation demethylation

CH3Hg(II)

• xidation

evasion

Hg(0)

sedimentation reduction diffusion resuspension diffusion resuspension Burial in Sediments

Wet Deposition and Dry Deposition of Gaseous and Particulate Hg

Bioaccumulation

• f CH3Hg

Watershed Retention and Transport/Runoff of Hg and CH3Hg Evasion from Soil and Vegetation Evasion

A: Major Ecosystem Inputs and Outputs of Mercury B: Major Aquatic Mercury Pathways

Hg(II)

methylation demethylation

CH3Hg(II)

• xidation

evasion

Hg(0)

sedimentation reduction diffusion resuspension diffusion resuspension

Hg(II)

methylation demethylation

CH3Hg(II)

• xidation

evasion

Hg(0)

sedimentation reduction diffusion resuspension diffusion resuspension Burial in Sediments

Biota

Source: Sunderland & Mason, 2007

B1 - Conceptual Overview

The Mercury Cycle

• Mercury impact is not directly related to its atmospheric burden, which is

mostly as Hg0, which has a low deposition velocity and is relatively

• insoluble. Oxidized forms of Hg are removed from the atmosphere more

readily.

• Given the long residence time of Hg0 in the atmosphere, this is the major

transport pathway for the global redistribution of Hg.

• Levels of MeHg in fish are used as the major environmental impact indicator
• f Hg contamination, and they respond both to changes in atmospheric Hg

inputs and composition, and changes in environmental conditions in the atmosphere and in aquatic ecosystems. The response time to changes in atmospheric oxidized Hg (RGHg) input is most rapid, with the response to changes in Hg0, and to other environmental variables being much slower.

• The current lack of understanding of a number of important processes in the

environmental cycling of Hg between the earth's surface and the atmosphere, and the transformations which take place in the atmosphere, make it almost impossible to predict the changes that might occur due to climate change. Without detailed information from a monitoring network, it will be very difficult to estimate the changes that may occur and to make accurate predictions of future trends.

B1 - Conceptual Overview

Major Findings

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• Studies are needed on possible measures to reduce the global

atmospheric Hg pool. Efforts to control the inputs of oxidized Hg will have more immediate benefit but long term reduction in the Hg0 content of the atmosphere is also needed to achieve the required health and environmental thresholds.

• More studies of the mechanisms of exchange of atmospheric

Hg with the aquatic environment are needed, and these fluxes need to be better quantified and constrained.

• Further studies of the atmospheric oxidation mechanisms of

Hg0 are needed as, in the absence of oxidized emissions; this is a critical process step between atmospheric Hg and its environmental impact.

B1 - Conceptual Overview

Recommendations

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Worldwide Mercury Measurements

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Worldwide Mercury Measurements

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Past Trends

Chemical analysis of lake sediments, ice cores and peat deposits from both hemispheres indicates about a threefold increase of mercury deposition since pre-industrial times

from: Lindberg, S., Bullock, R., Ebinghaus, R., Engstrom, D., Feng, X., Fitzgerald, W., Pirrone, N., Prestbo, E. and Seigneur C. (2007) A Synthesis of Progress and Uncertainties in Attributing the Sources of Mercury in Deposition. Ambio, Vol. 36, No. 1, pp.19-32.

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Monitoring of More Recent Change

• Asian mercury emissions are suggested to be rapidly

increasing at least in the past decade

• In principal, an increase of the global atmospheric Hg

pool should also be reflected in the background Hg concentration in ambient air.

• Regional differences, temporal trends and potential

sources and source regions can be identified by monitoring networks.

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Monitoring Network in the framework of MAMCS, MOE, MERCYMS

• 1. Mallorca (39°40’30” N, 2°41’36”E);
• 2. Calabria (39°25’N, 16°00’E);
• 3. Sicily (36°40’N, 15°l0’E);
• 4. Turkey (36°28’12”N, 30°20’24”E);
• 5. Israel (32°40’N, 34°56’E);
• 6. Germany (53°08’34”N, 13°02’00”);
• 7. Germany (54°26’14”N, 12°43’30”E);
• 8. Sweden (57°24’48”N, ll°56’06”E);
• 9. Sweden (58°48’00”, 17°22’54”E);

10.Ireland (53°20’N, 9°54’W)

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Source: Sprovieri et al. ACPD, 2010

Atmospheric and Air-Water Interface Studies since 2000

2000 2003 2004

2005 See special issue in: Atmospheric Environment 2001, 2003, 2005 Marine Chemistry 2007 Atmospheric Chemistry and Physics, 2010

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it Source: Sprovieri et al. ACPD, 2010

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it Source: Sprovieri et al. ACPD, 2010

Spatial characteristics of atmospheric Hg in U.S.

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it Source: Sprovieri et al. ACPD, 2010

Spatial characteristics of atmospheric Hg in U.S.

Hg0

Range of Means (ng/m3)

RGM

Mean - Max (pg/m3)

Hgp

Mean - Max (pg/m3)

Precip. [HgT]

Mean - Max (ng/L)

Sites near point sources (urban areas and mines (< 50 km)

2.3 - 4.4 7 - 385 16 - 1285 10 - 50

Sites influenced by regional point sources (< 500 km)

1.7 - 2.6 2 - 113 10 - 50 6 - 30

“Background” sites

1.5 - 1.7 2 - 30 2 - 63 4 - 20

High altitude site (3 km)

1.4 - 1.5 40 - 600 4 - 11 NA

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

CAMNet

Burnt Island

• St. Anicet

Alert Egbert

• Pt. Petre

Bratts Lake Kejimkujik Mingan Kuujjuarapik

• St. Andrews

Reifel Island Fort Chipewyan Esther Whistler Little Fox Lake ELA South Hampton CAMNet active

• ther

CAMNet closed

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it Source: Sprovieri et al. ACPD, 2010

 decreasing trend for TGM at several rural sites was seen from 1995 to 2005 (-2.2 to -16.6%);  changes are mostly driven by local or regional variations in Hg emissions;  other sites reflect hemispherical global background concentrations of airborne mercury, where slight decreases

• r no statistically significant trend in TGM concentrations

exist over the same time period. 11 CAMNet sites were analyzed for temporal trends (1995 - 2005)

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it Source: Sprovieri et al. ACPD, 2010

Current Global Hg-background Concentration

• In the Northern Hemisphere  1.5 to 1.7 ng m-3
• In the Southern Hemisphere  1.1 to 1.3 ng m-3

Key Sources: Sprovieri, F., Pirrone, N., Ebinghaus, R., Kock, H., and Dommergue, A. (2010) Worldwide atmospheric mercury measurements: a review and synthesis of spatial and temporal

• trends. Atmos. Chem. Phys. Discuss., 10, 1261-1307, 2010.

Lindberg, S., Bullock, R., Ebinghaus, R., Engstrom, D., Feng, X., Fitzgerald, W., Pirrone, N., Prestbo, E. and Seigneur C. (2007) A Synthesis of Progress and Uncertainties in Attributing the Sources of Mercury in Deposition. Ambio, Vol. 36, No. 1, pp.19-32.

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Long-term monitoring at single background locations The question of trends

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Long-Term Measurements at Mace Head from 1995 - today

Since 2003 funded by:

TGM (24 h av.), Mace Head, Ireland, 1995 - 2007 0.0 0.5 1.0 1.5 2.0 2.5 3.0

Aug/ 95 Jan/ 96 Jul/ 96 Jan/ 97 Jul/ 97 Jan/ 98 Jul/ 98 Jan/ 99 Jul/ 99 Jan/ 00 Jul/ 00 Jan/ 01 Jun/ 01 Dec/ 01 Jun/ 02 Dec/ 02 Jun/ 03 Dec/ 03 Jun/ 04 Dec/ 04 Jun/ 05 Dec/ 05 Jun/ 06 Dec/ 06 May/ 07 Nov/ 07

Since 2003 funded by:

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Alert Data: Schroeder, Steffen and co-worker; Mace Head Data: Ebinghaus, Kock and co-worker

TGM Conc. at Temperate and Polar Coasts

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Concentration data and trends  Mercury concentration measurements in ambient air of documented and accepted quality are available since the mid 1970 and concentration data are available for both hemispheres.  Long-term monitoring of atmospheric mercury with high time resolution has been started at Alert, Canada (January 1995) and Mace Head, Ireland (September 1995), followed by numerous other sites since then.  Consensus exists about the current global Hg0 background concentration with 1.5 to 1.7 ng m-3 in the Northern Hemisphere and 1.1 to 1.3 ng m-3 in the Southern Hemisphere (at sea level).  Competing hypotheses on trends in atmospheric TGM levels in the global atmosphere exist for the time period mid 1970 to 2000

B2 – Measurements

Major Findings

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Over water measurements  TGM measurements on board ships proved to provide valuable complementary information to measurements from the ground based monitoring network.  All cruises show a pronounced concentration gradient between the hemispheres with a ratio NH/SH: 1.45  The inter-hemispherical gradient with 30% higher TGM concentrations in the northern hemisphere remained nearly constant since mid 1970.  Open-ocean investigations have demonstrated the importance

• f air–sea exchange in controlling the Hg concentration in the
• atmosphere. Most studies, have revealed a net flux of Hg0

from the ocean into the atmosphere, based on the DGM saturation of the water phase.

B2 – Measurements

Major Findings

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Emission estimates and field observations  Asian emissions are considered to be of global importance and are suggested to be rapidly increasing in the past decade.  Experimental data show long-range transport across the Pacific and suggest a significant underestimate of Asian mercury emissions  Potentially increased Asian emissions are neither reflected in the long-term measurement of TGM at Mace Head (1995 – 2007), nor in the precipitation data of the North American MDN. The reason for this is not yet clear.

B2 – Measurements

Major Findings

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

AMDEs and global cycling  Atmospheric mercury depletion events (AMDEs) have been detected at numerous sites in the Arctic and Antarctic environment  Atmospheric mercury depletion events (AMDEs) have recently also been detected at a non-polar station (Cape Point), the chemistry involved seems to be different  We have limited understanding of the chemical cycling

• f mercury and other atmospheric components in

remote regions with seasonally variable sea-ice coverage.

B2 – Measurements

Major Findings

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Observational networks

 The establishment of a coordinated global monitoring network is highly

• recommended. This should incorporate already existing long-term-

atmospheric mercury monitoring stations and a number of additional sites, especially in the Southern hemisphere  Such a mercury network should be closely linked to existing sites with globally representative distribution and a long-term perspective, such as WMO GAW sites  It should be ensured that this measurement network is strongly supported my regional and global modelling, for scenario analysis and to support decision making for protecting human and environmental health.  The combination of intermittent shipboard and long-term ground measurements can provide information about the worldwide distribution and trend of atmospheric Hg. Occasional shipboard measurements should thus be a part of the global monitoring network for atmospheric Hg.  More effort should be dedicated to Deposition Networks with large spatial coverage and long-term perspective

B2 – Measurements

Recommendations

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Atmospheric chemistry and source attribution  We need a better understanding of the interplay of sources and removal processes since the spatial pattern of Hg concentrations in wet deposition has some aspects that cannot be fully reconciled.  We need a better understanding which sites would respond most quickly to changes in emissions and which sites are independent of local or regional sources and predominantly influenced by the global pool  We need more long-term data and spatial coverage to understand long-term changes in RGM and PM  Intercontinental transport of mercury can be estimated from Hg/CO measurements at fixed stations however, more emphasis should be addressed to the question why results based on this approach differ significantly from emission estimates, i.e. the possible underestimation

• f anthropogenic sources, the possibility of large and presently

unaccounted natural sources and erroneous speciation of anthropogenic emissions estimates

B2 – Measurements

Recommendations

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Polar regions

• Long term measurements of Hg0 and other atmospheric Hg species

in the Polar Regions are very limited and need to be increased.

• More research and investigation on possible reaction mechanisms

and chemical kinetics of atmospheric mercury in Polar regions are required to successfully improve our understanding of chemical- physical processes involved in the mercury cycle in order to assess the resulting net input into the polar biosphere.

B2 – Measurements

Recommendations

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Development of the GEO Task HE-09-02d

Status of Play:

 The European Commission just approved for funding the proposal “Global Mercury Observation System – GMOS “ with a total budget of about 9 M€.  GMOS Coordinator: Nicola Pirrone, CNR-IIA, Italy  GMOS involves 24 partners from all over the world.  GMOS will start in Nov. 2010 and will end in 2015.

An important contribution to the future development of the GEO Task HE-09-02d will be provided by GMOS in addition to the contributions from other countries that act as Co-Leads and as Contributors.

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

GMOS partnership

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

GMOS Overarching Objectives

 To establish a Global Observation System for Mercury able to provide ambient concentrations and deposition fluxes of mercury species around the world, by combining observations from permanent ground-based stations, and from

• ceanographic and tropospheric measurement campaigns.

 To validate regional and global scale atmospheric mercury modelling systems able to predict the temporal variations and spatial distributions

• f

ambient concentrations of atmospheric mercury, and Hg fluxes to and from terrestrial and aquatic receptors.  To evaluate and identify source-receptor relationships at country scale and their temporal trends for current and projected scenarios of mercury emissions from anthropogenic and natural sources.  To develop interoperable tools to allow the sharing of observational and models

• utput data produced by GMOS, for the purposes of research and policy

development and implementation as well as at enabling societal benefits of Earth

• bservations, including advances in scientific understanding in the nine Societal

Benefit Areas (SBA) established in GEOSS.

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

GMOS Ground-Based Observation System

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

GMOS Oceanographic Program

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

GMOS Aircraft-Based Program

B2 – Measurements

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

A Pirrone et al., 1996; B Pacyna et al., 2003; C Pacyna et al., 2006; D Streets et al., 2009b E Pirrone et al., 2008; F Pacyna et al., 2009; G Pirrone et al., 2009; H Pirrone et al., 2010

50 100 150 200 250 300 350 Pig iron and steel production Non-ferrous metal production Cement production Caustic soda production 100 200 300 400 500 600 Mercury production Commercial gold production Other Coal bed fires 50 100 150 200 250 300 350 VCM production Intentional use Artisanal gold prod. Cremation 200 400 600 800 1000 1200 1400 1600 Stationary combustion Waste disposal

A A B C D E F G H A A B C D E F G H

Global Anthropogenic Emissions of Mercury (Mg/yr)

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

A Pirrone et al., 1996; B Pacyna et al., 2003; C Pacyna et al., 2006; D Streets et al., 2009b E Pirrone et al., 2008; F Pacyna et al., 2009; G Pirrone et al., 2009; H Pirrone et al., 2010

500 1000 1500 2000 2500 3000 1989 2217 2427 2254 1894 2501 1926 2909 2320 Total (Anthropogenic)

A A B C D E F G H

Global Anthropogenic Emissions of Mercury (Mg/yr)

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 900.0 1000.0

Global Anthropogenic Emissions of Mercury (Mg/yr)

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Global Anthropogenic Emissions of Mercury (%)

South Africa 2% China 26% India 10% Australia 1% Europe 6% Russia 3% North America 7% South America 2% Rest of the World 43%

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Global Anthropogenic Emissions of Mercury (%)

Stationary combustion 35% Pig iron and steel production 2% Non-ferrous metal production 13% Cement production 10% Caustic soda production 7% Mercury production 2% Commercial gold production 17% Waste disposal 8% Coal bed fires 2% VCM production 1% Other 3%

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

A Bergan et al., 1999; B Mason and Sheu, 2002; C Lamborg et al., 2002; D Seigneur et al., 2004; E Selin et al., 2007; F Mason, 2009; G Pirrone et al., 2010

1000 2000 3000 4000 5000 6000 1999 2002 2002 2004 2007 2008 2008 5300 4200 3600 4278 4800 4532 5207 Total (Natural)

A B C D E G F

Total Oceans 51% Agricultural areas 2% Desert/Metallife rrous/Non- vegetated Zones 10% Tundra/Grasslan d/Savannah/Prai rie/Chaparral 9% Forest 7% Lakes 2% Evasion after mercury depletion events 4% Biomass burning 13% Volcanoes and geothermal areas 2%

B3 – Emissions

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Year Scenario North America Central and South America Africa Europe, Russia, Middle East Asia and Oceania World Reference 2020 SQ 142.8 53.6 74.1 222.7 1358.6 1851.9 [AMAP/UNEP, 2008] 2020 EXEC 66.2 31.0 35.0 112.3 604.4 852.3 [AMAP/UNEP, 2008] 2020 MFTR 54.3 27.4 27.9 94.6 462.1 666.1 [AMAP/UNEP, 2008] 2050 A1B 225.9 473.6 509.6 676.5 2970.0 4855.6 [Streets et al., 2009b] 2050 A2 239.1 415.6 375.5 667.3 2208.5 3905.9 [Streets et al., 2009b] 2050 B1 121.9 340.4 357.0 358.1 1208.9 2386.2 [Streets et al., 2009b] 2050 B2 131.3 331.2 308.1 398.0 1461.4 2629.9 [Streets et al., 2009b]

Mercury Emissions in 2020 and 2050 by Scenario and World Region

(Mg yr-1)

Ensemble mean estimates of Hg0 concentration in air

• B4. Global and regional modelling of Hg

Global Hg concentration and deposition levels

0.0 0.5 1.0 1.5 2.0 2.5

• 90
• 60
• 30

30 60 90 Latitude Hg0 concentration, ng/m

3

North America λ = 85ºW

0.0 0.5 1.0 1.5 2.0 2.5

• 90
• 60
• 30

30 60 90

Latitude Hg0 concentration, ng/m

3

λ = 10єE Europe 0.0 1.0 2.0 3.0 4.0

• 90
• 60
• 30

30 60 90 Latitude Hg0 concentration, ng/m

3

λ = 110ºE East Asia 0.0 0.5 1.0 1.5 2.0 2.5

• 90
• 60
• 30

30 60 90 Latitude Hg0 concentration, ng/m

3

λ = 150ºW Pacific Ocean

CTM-Hg GEOS-Chem GRAHM GLEMOS CMAQ-Hg ECHMERIT B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



The differences between models are largest in the regions of sparse measurements (e.g. oceans, the Arctic, South Asia, and Africa)



The largest uncertainty of simulated atmospheric deposition of Hg is associated with dry deposition

0.0 0.5 1.0 1.5 2.0 2.5 Arctic Europe & N.Africa North America East Asia South Asia Africa South America Australia & Oceania North Atlantic Pacific

Hg

0 concentration, ng/m 3

10 20 30 40 50 Arctic Europe & N.Africa North America East Asia South Asia Africa South America Australia & Oceania North Atlantic Pacific

Total deposition flux, g/km

2/y

CTM-Hg GEOS-Chem GRAHM GLEMOS CMAQ-Hg ECHMERIT

Hg0 concentration Hg deposition

Global Hg concentration and deposition levels

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



Multi-model source attribution study provides consistent estimates of source relative contributions despite the significant differences in emissions and chemistry between the models.

5 10 15 20 25 30 GEOS-Chem GRAHM GLEMOS CMAQ-Hg

Deposition flux, g/km

2/y

Europe

5 10 15 20 25 30 GEOS-Chem GRAHM GLEMOS CMAQ-Hg

Deposition flux, g/km

2/y

North America

Source attribution for Hg deposition

5 10 15 20 25 30 GEOS-Chem GRAHM GLEMOS CMAQ-Hg

Deposition flux, g/km

2/y

East Asia Europe North America East Asia South Asia Other Natural & re-emission

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



Intercontinental transport of Hg is significant, particularly in regions with few local emission sources. The contribution of foreign anthropogenic sources varies from 10% to 30%, on average in different regions

Contribution of intercontinental transport to Hg deposition

10 20 30 40 Arctic Europe North America East Asia South Asia Contribution of foreign sources, %

GEOS-Chem GRAHM GLEMOS CMAQ-Hg B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



Depending on applied emission scenario the change of Hg deposition between 2005 and 2020 will increase by 2-25% for SQ and decrease by 25- 35% for EXEC and MFTR in different industrial regions.

Future changes of Hg deposition

200 400 600 800 1000 1200 1400 Europe North America East Asia South Asia Other

Total emission, t/y 2005 2020 SQ 2020 EXEC 2020 MFTR

• 40
• 30
• 20
• 10

10 20 30

2020 SQ 2020 EXEC 2020 MFTR Relative deposition change, %

Europe

• 40
• 30
• 20
• 10

10 20 30

2020 SQ 2020 EXEC 2020 MFTR Relative deposition change, %

North America

• 40
• 30
• 20
• 10

10 20 30

2020 SQ 2020 EXEC 2020 MFTR Relative deposition change, %

East Asia

• 40
• 30
• 20
• 10

10 20 30

2020 SQ 2020 EXEC 2020 MFTR Relative deposition change, %

South Asia

Hg emission scenarios

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



The model uncertainties range from 20% for the simulated air concentration

• f Hg0, up to 80% for the simulated total deposition. The largest uncertainty of

total deposition is associated with dry uptake.

Evaluation of model uncertainty

0.6 1 2 5 0.6 1 2 5 Model, ng/m

3

Observed, ng/m

3

0.5 1 10 50 0.5 1 10 50 Model, g/km

2/y

Observed, g/km

2/y

CTM-Hg GEOS-Chem GRAHM GLEMOS CMAQ-Hg ECHMERIT

Hg0 air concentration Hg wet deposition flux

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



Intercontinental transport of mercury can occur through two pathways. One is the direct transport of emitted mercury plumes from one continent to

• another. The other pathway is through the mercury emission input of a source

region into the global mercury pool.



Contribution of foreign anthropogenic sources to annual deposition fluxes varies from 10% to 30%, on average anywhere on the globe. Besides, from 35 to 70% of total deposition to most regions consists of deposition contributed by global natural and secondary emissions



East Asia is the most dominant source region contributing to 10-14% Hg to deposition in other regions, followed by contributions from Europe (2-5%), South Asia (2-3%) and North America (1-2%)

Key findings (1)

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it



The large contribution of natural sources and secondary emission of legacy Hg reduces response of Hg deposition to the reduction in anthropogenic

• emissions. However, the response could be larger in the long-term perspective

due to the lagged effect of Hg recycling from planetary surfaces.



Depending on the applied emission scenario the change of Hg deposition between 2005 and 2020 will increase by 2-25% for SQ and decrease by 25- 35% for EXEC and MFTR in different industrial regions. In remote regions, such as the Arctic, the changes are expected to be smaller – from 1.5-5% increase (SQ) to 15-20% decrease (EXEC, MFTR).



The magnitudes of model uncertainties range from 20% for the simulated air concentration of Hg0, up to 80% for the simulated total deposition. However, the simulation results for the relative source attribution have a smaller uncertainty at about 30%.

• B4. Global and regional modelling of Hg

Key findings (2)

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



There is a need for a comprehensive interoperable measurement network for mercury in the environment to constrain models and track future mercury

• trends. Regular observations of wet and, in particular, dry deposition of Hg are

highly required for the improvement of model formulation and Hg deposition estimates



Better understanding of Hg chemistry through laboratory studies and field measurements are needed, particularly, for the gaseous and heterogeneous phase oxidation mechanisms, kinetics and products under different atmospheric conditions



Reliable assessment of intercontinental or global-scale dispersion of Hg requires development of multi-media biogeochemical models that take into account the entire cycle of Hg in the environment. It is particularly relevant for evaluation of long-term trends, future scenarios and the impact of climate change on mercury pollution

Recommendations (1)

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

• B4. Global and regional modelling of Hg



Model estimates of the effect of Hg intercontinental transport on regional pollution levels highly depend on the availability of reliable anthropogenic emissions data and, in particular, on speciation of Hg emissions. Therefore, further improvements of global Hg emission inventories are needed



In light of the importance of natural and secondary emissions for Hg concentration and deposition over the globe under current and future conditions, more studies are required for quantitative and mechanistic understanding of Hg emissions from various surfaces (soils, water, and vegetation)



More efforts are needed for elaboration of future Hg emission scenarios as well as the application of chemical transport models in evaluating future changes of Hg pollution levels

Recommendations (2)

B4 – Modeling

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

FINDING: Fish are the main source of human exposure to mercury. In regions that have not been contaminated by large local sources of mercury, the majority of population-wide human exposure is from marine fish consumption. Concentrations of mercury in commonly consumed migratory marine fish such as tuna and swordfish are affected by intercontinental transport and deposition of mercury to marine ecosystems. RECOMMENDATION: Reducing in global anthropogenic mercury sources is recommended as a method for reducing the mercury burden in pelagic marine fish and associated human exposures.

Contribution of Intercontinental Transport to Atmospheric Mercury Deposition

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Tilefish Shark Swordfish Orange Roughy Marlin Tuna-fresh Tuna-canned alb Bluefish Grouper, Rockfish Scorpionfish Halibut Sea trout Sablefish Snapper Lobster Mackerel Skate Tuna-canned lght Cod Croaker Squid Whitefish Pollock Crab

Figure 5.1. Reported mercury concentrations (ug/g wet weight) in fish sold in the U.S. commercial market. [Data from: U.S. FDA, 2006].

Figure 5.2. Seafood consumption and total mercury intake from estuarine and marine fish and shellfish in the U.S. commercial market. Left panel: Seafood consumption estimated from NMFS fisheries supply data compared with available data for marine and estuarine fish consumption from the continuing study of food intake by individuals (CSFII) dietary survey data [U.S. EPA, 2002]. Right panel: Percentage of total mercury intake (product of seafood supply and mercury concentrations) for the top 15 seafood categories; intake is allocated by the source region for each of the fisheries products [Atlantic, Pacific, imported (foreign sources), and high seas landings]. “Salmon” includes both canned and fresh and frozen products; “Anchovies et al.” includes anchovies, herring, shad, and sardines; “Flounders” includes flounder, plaice, and sole; “Haddock et al.” includes haddock, hake, whiting, and monkfish; and “Grouper et al.” includes grouper and seabass

FINDING: Fish consumption patterns differ across geographic regions and vary according to traditional diets, recreational activities, and proximity to supply of fresh seafood products [Mahaffey et al., 2009; Moya, 2004]. Individual variability in mercury exposures across populations reflects these differences as well as the types and origins of seafood products consumed. RECOMMENDATION: Effectively managing MeHg risks requires information on the exposure pathway at both local and global scales. Most fish consumed globally are marine and estuarine species harvested from open ocean

• environments. Thus, understanding the impacts of

intercontinental mercury sources on the distribution of mercury in open-ocean environments is especially important.

Impact on Human Health

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Terrestrial Ecosystems

Figure 5.4. Soil storage and emissions of mercury in soils simulated by the model for pre-industrial and present-day conditions. Anthropogenic enrichment is computed as the difference between present-day and pre- industrial budgets. Source: Smith-Downey et al. [2010].

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Terrestrial and Frewater Ecosystems

FINDING: Adverse impacts from recent and current anthropogenic mercury inputs into the environment is documented across broad areas of North America on fish, birds, and mammals. Because the ability to predict MeHg impacts in upper trophic level wildlife using models and measurements of air, sediment and water is presently limited, additional biological field sampling efforts are needed to reach a level of certainty for science-based decision- making. RECOMMENDATION: Based on recent advances in developing statistically- replicable and defensible field experiments for identifying LOAELs the use of wildlife for monitoring spatial gradients and temporal trends of environmental mercury loads related to atmospheric deposition is possible. Preliminary results suggest that intercontinental mercury transport contributes to adverse effects of mercury exposure on ecological health.

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Polar Ecosystems

FINDING: Observations made in the polar regions constitute direct evidence of a link between sunlight-assisted Hg(0) oxidation, greatly enhanced atmospheric Hg(II) wet and/or dry deposition, and elevated Hg concentrations in the polar snow-pack. Antarctic and Arctic coastal sites experience episodic mercury depletion events, which occur predominantly in the late winter and early spring. Polar regions receive most of their mercury from intercontinental transport and are highly susceptible to the effects of climate driven changes in atmospheric and

• ceanographic circulation.

RECOMMENDATION: Further investigation is needed on the unique reactivity of mercury place in the troposphere of polar regions and the contribution of

• xidized mercury from these regions to the global budget of atmospheric Hg. In

addition, the role of snow and ice surfaces on deposition in these regions requires elucidation, including both experimental monitoring and modeling studies.

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Marine Ecosystems

Figure 5.5. Atmospheric Hg(II) deposition from Asian sources

• ver the North Pacific Ocean. Source: Strode et al. [2008].

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Marine Ecosystems

Intercontinental transport from major hydrographic circulation patterns in the oceans

Figure 5.6. Surface water total mercury concentrations in the North Pacific Ocean. Source: Sunderland et al. [2009].

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Marine Ecosystems

Intercontinental transport from major hydrographic circulation patterns in the oceans

Figure 5.7. Enrichment of total mercury concentrations in intermediate waters of the North Pacific Ocean. Sources: [Laurier et al., 2004; Sunderland et al., 2009].

The enhanced local contribution to deposition off the Asian continent (Figure 5.5) that is also

• bserved as enriched surface seawater concentrations (Figure 5.6) is the probable source of

enriched immediate water mass concentrations in the eastern North Pacific (Figure 5.7).

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Impact on Marine Ecosystems

FINDING: Global changes in open ocean mercury concentrations can be attributed to intercontinental mercury transport as part of the global pool and localized deposition of mercury plumes from large source regions such as Northeastern Asia. In addition to atmospheric transport, large-scale oceanic transport can also be responsible for long-range transport of mercury from the original emissions source and likely impact marine fish concentrations globally. RECOMMENDATION: Additional research is needed on the importance of large scale oceanographic currents for redistributing mercury deposited in nearshore regions from concentrated source regions and coastal pollution sources.

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Implications for Policy

Present 2050 A1B 2050 B1 2050 A2 2050 B2

Figure 5.9. Modeled future mercury deposition scenarios for Asia based on the emissions scenarios developed by Streets et al. [2009]. Source: Corbitt et al. [2010].

B5– Impact

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Implications for Policy

Figure 5.11. Temporal evolution of fish MeHg source attributions for various model lake ecosystems to deposition scenarios for the Northeast and Southeast United States. Source: [Selin et al., 2010].

CNR-Institute of Atmospheric Pollution Research, Rome, Italy http://www.iia.cnr.it

Thanks…..