Hg

A brief human history of mercury poisoning Qin Shi Huang, 1 st emperor of China Mad hatters Minimata disaster Karen Wetterhahn, Dartmouth professor Iraq grain disaster 200 BC 19 th -20 th century 1950s

The perils of eating too much fish Jeremy Piven, actorRichard Gelfond, IMAX CEO Both hospitalized for extended time due to mercury poisoning from daily fish consumption over many years

Mercury from fish consumption: a global environmental issue Children IQ deficits (fetal exposure) Well-established $8 billion per year cost in US Adult cardiovascular effects Suspected EPA reference dose (RfD): 0.1 μg kg -1 d -1 (about 2 fish meals per week) Hg (mg/kg) Tilefish Shark Swordfish Orange Roughy Marlin Canned Tuna (alb) Bluefish Grouper, Rockfish Scorpionfish Halibut Sea trout Sablefish Lobster Snapper Lobster Mackerel Skate Canned Tuna (lt) Cod Croaker Squid Whitefish Pollock Crab Mercury biomagnification factor Salmon

Mercury is a particularly important issue in the Arctic High mercury concentrations, dependence on populations on seafood

Mercury is present in the atmosphere as an elemental gas Argon CO 2 Water vapor Oxygen Helium Mercury Nitrogen It is the only metal that behaves that way!

Natural cycle of mercury mercury burial SEDIMENTS uplift volcanoes erosion mercury HUMAN PERTURBATION: coal combustion mining ATMOSPHERE OCEAN/SOIL deposition re-emission food chain

Rising mercury in the environment Dietz et al. [2009] Mercury in Wyoming ice coreMercury in Arctic wildlife Human perturbation started in Antiquity; present-day mercury levels in global environment are about ten-fold higher than natural

Global transport of mercury through the atmosphere Circle around mid-latitudes: 1 month Transport to southern hemisphere: 1 year Implies gPresent-day cale transport of anthropogenic emissions Mercury emitted anywhere can deposit to oceans worldwide Present-day emission of mercury to atmosphere from coal and mining Atmospheric concentrations UNEP [2013]; Soerensen et al. [2013]

UNEP Minimata Convention on Mercury First major global environmental treaty in over a decade Requires best available technology for coal-fired power plants Mercury mining to be banned in 15 years Regulation of mercury use in artisanal gold mining Opened for signatures in October 2013; signed by 128 countries so far Convention requires ratification by 50 countries to go into effect; twelve (including the US) have ratified so far signed ratified

“Grasshopper effect” keeps mercury in environment for decades Amos et al. [2014] Reservoir fraction Fate of an atmospheric pulse: Atmosphere Surface soils Deep soils Surface/subsurface ocean Coastal sediments Deep sediments Deep ocean mercury deep ocean rivers SEDIMENTS Land Ocean 0 Helen Amos (Harvard)

Who is responsible for mercury in the present-day ocean? Amos et al. [2013] Europe Asia N America S America former USSR Rest of world pre-1850 natural by time of initial emission: by source continent: Half of human-derived mercury presently in the ocean was emitted before 1950

Atmospheric mercury has been decreasing since 1990, despite increasing emissions from coal combustion Why? Zhang et al. [2015] Long-term atmospheric data Long-term precipittation data BLUE = DECREASE RED = INCREASE Yanxu Zhang (Harvard)

Many commercial products contain(ed) mercury Wiring Devices & Industrial Measuring Devices Medical Devices Pharmaceuticals & Personal Care Products

Pesticides and Fertilizer Explosives/Weapons Dyes/Vermilion Many commercial products contain(ed) mercury

Global historical use of mercury in commercial products Horowitz et al. [2014] Consumption, Mg per year Year AD Artisanal gold mining Hannah Horowitz (Harvard)

Tracking the environmental fate of commercial mercury content/uploads/2012/07/sewage.jpg; symbol.jpg Global mercury mined per decade Commercial use by country Disposal Air Land Water Landfill

Additional releases from commercial Hg in the context of atmospheric emissions Estimate: –“Distribution factors”: fraction of Hg entering each pathway –“Release factors”: fraction of Hg released into air, water, land Historical release of commercial mercury to the environment Hannah Horowitz (Harvard). “Inadvertent” mercury (coal combustion, silver/gold mining) Air Soil Water Landfills Commercial mercury Total release peaked in 1970, has been decreasing since

Atmospheric mercury in the Arctic is high and not decreasing; WHY? trend BLUE: decrease RED: increase Atmospheric mercury concentration Jenny Fisher (Harvard) Fisher et al. [2013], Chen et al. {2015]

What is going on in the Arctic? Large river inputs to shallow Arctic Ocean; melting sea ice allows mercury to escape Ocean mercury, pM mercury Northern Dvina in Arkhangelsk

The wild card of climate change: potential mobilization of the large soil mercury pool Global soils: 270,000 tons mercuryOceans: 330,000 tons Atmosphere: 5,000 tons Increasing soil respiration due to warmer temperature Climate change may be as important as emission controls for the future of environmental mercury in the century ahead.