Hgtrend050422
-
Upload
rudolf-husar -
Category
Technology
-
view
458 -
download
0
description
Transcript of Hgtrend050422
Anthropogenic Mercury Mobilization and Emissions in US and Florida, 1930-2000
Janja D. Husar and Rudolf B. HusarWashington University,
St. Louis, Missouri
Supported by
Florida Department of Environmental Protection
Tetra-Tech, Inc
Health and Environmental Concerns
• Elevated mercury concentrations are present in the upper levels of the food chain in southern Florida and Upper Midwest.
• Recently, Northeast has been added to the warning list, NY Times, April, 2005
• Warnings issued predominantly to pregnant women and children
The importance of mercury (Hg) as an environmental contaminant stems from its omnipresent nature, due largely to the magnitude of sources, its volatility, mobility, and persistence.
Mercury Sources
Mercury is a building block of planet Earth (trace element). Mercury metal is liquid and evaporates, depending on temperature and barometric pressure. Natural systems, wind, rain, volcanic disturbances shift mercury location.
MAN-MADE sources add to the environmental burden by taking mercury from its geological deposits and redistributing mercury to AIR , LAND and WATER.
Mercury in environment is either in elemental form or reactive gaseous mercury (RGM).Atmospheric residence time Hgo order of 90 daysHg2+ (RGM) order of days.
Biomagnifications of Hg
• Atmosphere is a transmission medium – no accumulation• Mercury is concentrated in the food chain.
Approach for Assessment of Anthropogenic Mercury
Multi-Scale: National, Florida, Southern Florida
Mercury Inputs
Mercury in goods
Mercury in fuels
Mercury mobilized in coal
• Each coal mining region has a specific Hg content; USGS has extensive data for each coal region
• Hg mobilization = (Hg Conc. X Coal Production)
• Most of coal in FL is from the Appalachian Basin
• The total Hg mobilized in coal has been 80-160 Mg/yr since 1900
• The Hg fraction emitted during combustion is 50-75%
• The coal Hg emission ranged 60- 120 Mg/year
Mercury Mobilized in Petroleum
Unlike for coal, the Hg content of crude oil is highly variable and the data are sparse.
Measured crude oil Hg concentration ranges between 10 and 30,000 ppb.
“Other” still gas, naphtas, unfinished oils, petroleum coke (consumed at refineries
and electric utilities), etc
Fate of Hg in Crude Oil
Assuming 10 ppb in crude oil
Hg conc, ppb
LPG 10
Distillate fuel 5
Motor gasoline 2
Residual fuel 10
Other 50
US Mercury Mobilization Trend
Hg Mobilization:Fuels
- Coal- Crude Oil
Goods– Chlor-alkali– Pharmaceuticals– Agriculture,
fungicide
– Paint, fungicide
– Lab use– Electrical, batteries
– Control, manometers – Dental, amalgamation
– Other
Data: Bureau of Mines (BOM), USGS, and DOE
Mercury Mobilized in Goods: Electrical Sector
• Batteries were dominant until 1990
• Hg in alkaline batteries were discontinued, beginning the 1980s
• Hg is still used in lights and switches
• Consistency of ‘electrical’ Hg use:• Bureau of Mines reports Hg consumption
• Franklin reports Hg in discarded goods
Mercury in Paint
• Phenyl mercuric compounds used as fungicide in water-type (latex) interior and exterior paints
• Water-type paint consumption was increasing since the 1950s
• The average paint Hg concentration (Hg used/Water Paint shipped) was declining from >300 ppm
Mercury Flow in Goods
Mercury NOT distributed with goods• Chlor-alkali - 14,000 Mg/70yrs
Mercury distributed with goods• Pharmaceuticals – 3,400 Mg/70yrs
• Agriculture - 5,400 Mg/70yrs
• Paint - 8,400 Mg/70yrs
• Lab use – 1,800 Mg/70yrs
• Electrical – 29,000 tons/70yrs
• Control – 10,000 Mg/70yrs
• Dental – 3,200 Mg/70yr
Data: Bureau of Mines (BOM), USGS, and DOE
Mobilized in 70 years ~112,000 Mg
Mercury Mobilization -> Atmospheric Emissions
• Atmospheric emission fraction is estimated for each mercury flow category• Emission = Hg flow in goods and fuels * Emission fraction
Electrical
Control
Lab use
Dental
Pharmaceuticals
Petroleum
Coal
Paint
Agriculture
50-75% Air
100%
66% Air100%
AIR
Land
Air+Land
Mercury Emissions: USA
• The US mercury emissions were estimated based on the Hg flow and emission fractions• Nationally, coal combustion and electrical use contributed the bulk during 1930-1990 • Note the the significant paint contribution to the atmospheric emissions, 1960-1990
Mercury Flow: US -> Mercury Flow: Florida
Electrical
Control
Lab use
Dental
Pharmaceuticals
Paint
Coal
Petroleum
AgricultureAcreage use prorated
Population prorated
Florida specific
Mercury Flow: US Mercury Flow: Florida
Mercury in Coal and Petroleum: Florida
• The Hg mobilized in coal increased to about 5 Mg/yr
• The coal Hg emission ranged 2.5 - 4 Mg/year in the 1990s
E Kentucky
Source of Coal Hg
• The Hg in oil products reached ~0.2 Mg/yr
• Motor gasoline and residual fuel oil are the main contributors
•Note that petroleum Hg is <<< Coal Hg
Mercury Flow in Florida
Mercury flow in Florida has been steadily increasing until the 1980s
The electrical sector (batteries) was dominant throughout the period
The electrical sector contributed 50% of the cumulative Hg flow (1930-2000).
Cumulative Hg Flow: ~2000 Mg/70 yrs
Waste Combustion Fraction and Rate
• The emission fraction of municipal waste was between 10 and 30% for the US
• The decline (1960-1980) was due to closing of incinerators
• Recent increase is due to regulated incineration (WTE) units
• Paint mercury in FL occurred in 1960-1990• Assuming 75% emission fraction, the emission
rate was ~8 Mg/yr for 1970-1990.
Mercury Emissions:US and Florida
• The US Hg emission ranged between 300-500 Mg/yr (1940-1990).
• The Florida Hg emissions have increased from 5 to 15 Mg/yr during the 1940-1990 period.
• Nationally, coal was a significant contributor throughout the period.
• In Florida, coal became significant in the 1990s
Mercury Emissions: Comparison of Florida DEP – Material Flow Method
• In the 1990s, the Hg content of goods and paints has declined dramatically due to environmental regulations.
• Hg from coal combustion became comparable to the Hg in goods.
• The mercury emissions were estimated by the Florida DEP for Waste to Energy (WTE) incinerators.
• The corresponding (electrical, lab, control) emission estimates by the material flow method yield similar results.
Broward County mercury flow and emissions
Paint and electrical goods contribution was the largest in the Broward County.
Summary
• Hg mobilization is driven by combustion of Hg containing fuels (coal and oil) and by Hg use for goods (batteries, instruments, paints) .
• The US mercury mobilization peaked in 1960-1990 period at about 2000 Mg/yr, followed by sharp decline in the 1990s due to environmental regulations.
• The peak US atmospheric mercury emission rate was about 400 Tons/yr in the 1960-1990 period.
• In Florida, the mercury flow and emission rate has increased rapidly in the late 1960s, and dropped sharply in the 1990s.
• The Hg flow and emission trends for Florida are now being reconciled with other data as part of the FCG and FL-DEP Mercury Trend Project.
Waste Combustion Fraction and Rate
• The emission fraction of municipal waste was between 10 and 30% for the US
• The decline (1960-1980) was due to closing of incinerators
• Recent increase is due to regulated incineration (WTE) units
• Data
Mercury in Agriculture: Florida
• Florida mercury agriculture use
Comparison of RMB and flow method
• Three county comparison. Electrical, control, and lab use were incinerated at reported WTE rates, for 1990-1998. 1980-1980 incineration was apportioned using Florida factors
Mercury Flow Methodology
• Flow method is based on mass balance applied to environmental compartments
• Mercury flow through the ‘environment’ begins by mining of minerals and fuels
• Along the flow, mercury is discarded to air, land and water