Mercury in the West*

Land and Water Fund of the Rockies

and

Rocky Mountain Office of Environmental Defense

January 2003

*The information in this presentation is largely drawn from the white paper “A Closer Look at Mercury in the West” prepared by Paulette Middleton for the Land and Water Fund of the Rockies and Environmental Defense (http://panoramapathways.net/mercuryinthewest.pdf)

Mercury Overview

Hg is present in the earth’s atmosphere in the form of elemental vapor, reactive (i.e., oxidized) gaseous Hg, and particulate Hg

Hg that gets into aquatic ecosystems through atmospheric deposition or soil runoff can be transformed into an extremely toxic organic methylmercury which bioaccumulates up the food chain as humans and animals consume contaminated organisms such as fish

Mercury Overview - II

Children and fetuses, because they are in rapid developmental stages, are particularly susceptible to the harmful neurological effects of methylmercury

In a 2000 report, the National Academy of Sciences’ National Research Council estimated that each year about 60,000 children may be born in the U.S. with neurological problems that could lead to poor school performance because of exposure to methylmercury in utero

Mercury Fate and Transport

Because of differences in the forms of Hg and its transport behavior, populations can be placed at risk from Hg that may have come from local sources, a different state, or a different part of the world

In the US, both the West and East are source regions of mercury as well as affected areas

Mercury Fate and Transport - II

The more reactive gaseous forms of Hg can be deposited on land and water much closer to the sources

Elemental Hg can persist in the atmosphere and be transported longer distances, but is a substantial contributor to Hg concentrations in land and water especially in remote areas where atmospheric transport is the main mechanism of contamination

All airborne Hg also can undergo chemical reactions that lead to Hg compounds that are more readily deposited

Mercury Fate and Transport – IIILong-range vs. Short-range

Quantification of transport is a matter of on-going investigation Grumet (former NESCAUM) estimates that 47% of Hg deposited in the

Northeast comes from within that region, 30% from other US sources and 23% from global sources (http://www.eerc.und.nodak.edu/catm/graphics/v7i1part2.pdf)

Levin suggests that Hg deposition is concentrated in areas close to sources, that Asian emissions account for 10-20% of deposition on the West Coast, and that non-anthropogenic sources contribute 4-7% in the East and 10-12% in the West (same cite)

Based on modeling, Bullock (NOAA) estimates that 25-30% of the deposition in the US comes from global background, the rest from US sources (http://pubs.acs.org/hotartcl/est/98/apr/mer.html)

Comparing lake sediment core samples from MN and coastal AK, Swain (MN Pollution Control Agency) estimates that 40% of Hg is due to regional anthropogenic sources (same cite)

Modeling analysis by Seigneur (AER, Inc.) suggests that global background accounts for about 70% of Hg deposition in the US

Sources of U.S. Anthropogenic HgSource: EPA Mercury Report to Congress (1997)

About 158 total tons of Hg are emitted in the US each year

4 source categories are responsible for about 80% of total anthropogenic Hg:

– Coal-fired utilities are largest source at 33%

– Municipal waste combustors (19%)– Commercial/industrial boilers (18%)– Medical waste incinerators (10%)

Coal-fired power plants are largest uncontrolled anthropogenic source of Hg

Coal-fired Power Plant Hg Emissions

US Coal-fired units emitted 48 tons of Hg in 1999 Speciation: about 3% particulate, 43% reactive

gaseous, and 54% elemental Breakdown varies from plant-to-plant depending

on type of coal being burned and emission controls in place

Total Hg emissions are higher in the East than in the West, as expected, since utility emissions are much higher in the East

NM is highest in West and ranks 15th nationallySource: EPA 1999 Information Collection Request

Western Coal-fired Power Plant Hg Emissions

Source: EPA 1999 Information Collection Request

0

0.2

0.4

0.6

0.8

1

1.2

NM WY AZ MT WA CO NV UT OR CA

Hg from PowerPlants (tons/yr)

The West Has High Levels of Mercury Contamination

Although there are limited monitoring sites in the West, recent observations of Hg concentration and deposition indicate that Hg levels in the West are similar to those in the East

In fact, New Mexico had the highest average atmospheric Hg concentration in U.S. for 2000

Colorado had a high total wet deposition level in 2000, comparable to eastern monitoring sites

SOURCE: National Atmospheric Deposition Program, Mercury Deposition Network

Annual Average Mercury Atmospheric Concentrations, 2000

National Atmospheric Deposition Program, Mercury Deposition Network

Total Annual Mercury Wet Deposition, 2000

National Atmospheric Deposition Program, Mercury Deposition Network

Hg Monitoring in the West

The western NADP sites indicated on the preceding maps are:– Buffalo Pass, Routt County, Colorado– Caballo, Sierra County, New Mexico– Seattle, King County, Washington– San Jose, Santa Clara County, California– Covelo, Mendocino County, California

Fish and Wildlife Advisories

If high concentrations of Hg or other chemicals are found in local fish and wildlife, states or tribes may issue a consumption advisory

Virtually every western state (except Wyoming) had active fish consumption advisories for specific water bodies in 2000

Fish Consumption Advisories by State for 2000

Total Number of Fish Consumption Advisories — 2000(Change from 1999)

Note: The numbers depicted here do not necessarily reflect the geographic extent of the chemical contamination in each state or the extent of the state’s monitoring effort. Source: NLFWA, December 2000

Current advisories issued for:MercuryPCBsChlordaneDioxins34 other chemicals.

Advisories are in effect in:63,288 lakes, representing 23% of our Nation’s lake acres

9.3% of our Nation’s rivers miles

100% of the Great Lakes71% of coastline of contiguous 48 states.

Number of advisories in the US in 2000 represents a 7% increase over 1999; 124% increase since 1993.

48 states, the District of Columbia, and 1 US territory and 8 Canadian provinces and 1 Canadian territory have fish advisories.

48 states and 1 US territory and 7 Canadian provinces and 1 Canadian territory have waterbody-specific advisories

14 states and the District of Columbia have statewide advisories and 2 Canadian provinces have provincewideadvisories for lakes and/or rivers

15 states have all of their marine coastal waters under advisory.

NOTE: This map depicts waterbodieswhere fish consumption advisories were in effect in 2000 based on information provided to the USEPA by the states in December 2000 and Canadian provinces in December 1997. Because only selected waterbodiesare monitored, this map may not reflect the full extent of chemical contamination of fish tissues in each state or province. EPA US Fish and Wildlife Contamination Progrram

LEGEND

Source : NLFWA, December 2000

LEGEND

Location of Waterbodies under Consumption Advisories, by Pollutant – 2000

Western Mercury Advisories

The table in word format accompanying this presentation lists mercury advisories for waterbodies in western states

Advisories are in effect for waterbodies across the West

Mercury Control Options for Western Power Plants

The EPA Information Collection Request analysis indicates that subbituminous coals emit relatively more elemental Hg than bituminous coals

Both elemental and reactive gaseous Hg can be absorbed onto porous solids such as fly ash, powdered activated carbon or calcium-based acid gas sorbents for subsequent collection in a PM control device such as a fabric filter

Mercury Control Options – IIWestern Power Plants

Powdered activated carbon (PAC) injection has been successfully demonstrated for about 10 years on med waste incinerators, mun waste combustors and haz waste combustors

The activated carbon is injected before the fabric filter and, if necessary, a water mist used to cool the flue gas

In cases where a spray dryer fabric filter system is used, the gas cooling occurs in the spray dryer and no mist is necessary

Mercury Control Options – IIIWestern Power Plants

The EPA Information Collection Request data also indicate that chemistry associated with the selective catalytic reduction (SCR) systems may be enhancing the oxidation of Hg and, as a result, increasing capture efficiency

How it Works: SCR processes designed to reduce NOx by converting NOx to N2 can enhance the oxidation of Hg to forms that are more readily captured