Hg
Hg
A brief human history of mercury poisoning
Qin Shi Huang,
1st emperor of China
Mad hatters
Minimata disaster
Iraq grain disaster
200 BC
Karen Wetterhahn,
Dartmouth professor
19th-20th century
1950s
1971
1997
The perils
of eating too much fish
Jeremy Piven, actor
Richard Gelfond, IMAX CEO
Both hospitalized for extended time due to mercury poisoning
from daily fish consumption over many years
Children IQ deficits (fetal exposure)
Well-established
$8 billion per year cost in US
CodCod
Croaker
Croaker
Squid
Squid
Whitefish
Whitefish
Pollock
Pollock
Crab
Crab
Salmon
1.4
Tuna-canned alb
Bluefish
Bluefish
Grouper, Rockfish
Grouper, Rockfish
Scorpionfish
Scorpionfish
Halibut
Halibut
Sea trout
Sea trout
Sablefish
Sablefish
Lobster
Snapper
Snapper
Lobster
Lobster
Mackerel
Mackerel
Skate
Skate
Tuna-canned
lght
(lt)
Canned Tuna
Orange Roughy
Orange Roughy
Marlin
Marlin
Tuna-fresh
Canned Tuna (alb)
Tilefish
Tilefish
Shark
Shark
Swordfish
Swordfish
Hg (mg/kg)
Mercury from fish consumption: a global environmental issue
EPA reference dose (RfD): 0.1 μg kg-1 d-1 (about 2 fish meals per week)
Adult cardiovascular effects
Suspected
1.6
Mercury biomagnification factor
1.2
1.0
0.8
0.6
0.4
0.2
0.0
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
Nitrogen
Oxygen
Helium
Mercury
Water
vapor
Argon
CO2
It is the only metal that behaves that way!
Natural cycle of mercury
HUMAN
PERTURBATION:
coal combustion
mining
mercury
deposition
volcanoes
erosion
re-emission
ATMOSPHERE
OCEAN/SOIL
mercury
uplift
food chain
burial
SEDIMENTS
Rising mercury in the environment
Mercury in Wyoming ice core
Mercury in Arctic wildlife
Dietz et al. [2009]
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
Present-day
emission
mercury to
fromemissions
coal and mining
Implies
gPresent-day
caleoftransport
ofatmosphere
anthropogenic
Atmospheric concentrations
Circle around mid-latitudes:
1 month
Transport to southern hemisphere:
1 year
Mercury emitted anywhere
can deposit to oceans worldwide
UNEP [2013]; Soerensen et al. [2013]
UNEP Minimata Convention on Mercury
First major global environmental treaty in over a decade
Opened for signatures in October 2013; signed by 128 countries so far
• 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
signed ratified
Convention requires ratification by 50 countries to go into effect;
twelve (including the US) have ratified so far
“Grasshopper effect” keeps mercury in environment for decades
mercury
Land
Ocean
rivers
deep ocean
SEDIMENTS
Reservoir fraction
Fate of an atmospheric pulse:
Atmosphere
Surface soils
Deep soils
Coastal sediments
Deep sediments
0
Helen Amos (Harvard)
Amos et al. [2014]
Who is responsible for mercury in the present-day ocean?
by time of initial emission:
by source continent:
natural
pre-1850
Rest of world
Half of human-derived mercury
presently in the ocean
was emitted before 1950
former
USSR
N America
S America
Europe
Asia
Amos et al. [2013]
Atmospheric mercury has been decreasing since 1990,
despite increasing emissions from coal combustion
Long-term atmospheric data
Long-term precipittation data
BLUE = DECREASE
RED = INCREASE
Why?
Yanxu Zhang (Harvard)
Zhang et al. [2015]
Many commercial products contain(ed) mercury
Medical Devices
Wiring Devices &
Industrial Measuring Devices
Pharmaceuticals & Personal Care Products
Many commercial products contain(ed) mercury
Dyes/Vermilion
Pesticides and Fertilizer
Explosives/Weapons
Global historical use of mercury in commercial products
Consumption, Mg per year
Artisanal gold mining
Year AD
Hannah Horowitz (Harvard)
Horowitz et al. [2014]
Tracking the environmental fate of commercial mercury
Global mercury mined
per decade
Commercial use by country
Disposal
Land
Air
Landfill
Water
Additional releases from commercial Hg in the context of atmospheric
Historical release of commercial mercury to the environment
emissions
Water
Landfills
Soil
Air
Commercial mercury
Total release peaked in 1970,
has been decreasing since
“Inadvertent” mercury (coal combustion, silver/gold mining)
Hannah Horowitz (Harvard).
Atmospheric mercury in the Arctic is high and not decreasing;
WHY?
Atmospheric mercury concentration
2000-2009 trend
BLUE: decrease
RED: increase
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
Northern Dvina in Arkhangelsk
mercury
mercury
Ocean mercury, pM
The wild card of climate change:
potential mobilization of the large soil mercury pool
Atmosphere: 5,000 tons
Increasing soil respiration
due to warmer temperature
Global soils: 270,000 tons mercury
Oceans: 330,000 tons
Climate change may be as important as emission controls
for the future of environmental mercury in the century ahead.