Trace Elements in West Virginia Coals

MERCURY (Hg)

Mercury is an environmentally important Clean Air Act, Title III Hazardous Air Pollutant element of considerable environmental concern because mercury is highly toxic and extremely volatile during coal combustion.

Geologic Distribution: Mercury in coal appears to occur within pyrite, sometimes sphalerite, and possibly organically bound ¹. In various U.S. coals a good correlation was found between mercury and pyritic sulfur ². Sphalerite in Illinois coals was shown to contain mercury ³. Some Russian coals contain considerable Hg in the forms of the mineral cinnabar (HgS), metallic Hg and in organomercury compounds near areas of mercury mineralization areas ¹. Mean whole coal mercury in West Virginia coals was 0.19 ppm, and despite published relationships, no statistical correlation was noted between pyritic sulfur and Hg, but total sulfur and arsenic correlated slightly with Hg. Mercury, however, did correlate somewhat with thallium (Tl) on a whole coal basis. Mercury content in West Virginia coals was generally very low and variable. Upper Pennsylvanian coals consistently contained 0.1-0.3 ppm mercury. Middle Pennsylvanian coals exhibited lower mercury contents and Lower Pennsylvanian coals exhibited low but erratic mercury abundances. Highest Hg content coals were in thin, high sulfur, and generally unminable upper Allegheny and Conemaugh group (Lower Kittanning through Harlem: see the historic coal production) coals in Monongalia, Preston and Mineral counties (see cautionary note page).

Economic Impact: Future regulations restricting the allowable amount of mercury in coal used for combustion could possibly impact a few minor and generally unmined coals in West Virginia. Mercury has a vast range of important economic uses.

Environmental Impact: There are important natural sources of atmospheric Hg including volcanoes and hot springs, volatilization from vascular plants and degassing from land and water ¹. Industrial sources of atmospheric Hg include cremation, cement making, and of course coal combustion ¹. Mercury is volatilized in the combustion of coal, but varying amounts of Hg are retained in fly ash, resulting in less atmospheric emission ¹.

References:
    1. Swaine, D.J., (1990)
    2. Finkelman, R.B., (1981)
    3. Cahill, R.A. and Shiley, R.H., (1981)
    4. Finkelman, R.B. and Tewalt, S.J., (1998)

Mercury related EPA fact sheets

EPA (Environmental Protection Agency), 2000, EPA to Regulate Mercury and Other Air Toxics Emissions from Coal- and Oil-Fired Power Plants. December 14, 2000. Adobe Acrobat file: http://www.epa.gov/ttn/oarpg/t3/fact_sheets/fs_util.pdf

EPA (Environmental Protection Agency), 1998a, Mercury emissions and electric utilities. February 24, 1998.

EPA (Environmental Protection Agency) , 1998b, Mercury study report to Congress: White Paper. February 24, 1998.

To request specific information from a Survey geologist click here.

Page last revised: March 2, 2002

Please send questions, comments, and/or suggestions to webmaster.

Page created and maintained by:
            West Virginia Geological & Economic Survey
  Address:  Mont Chateau Research Center
            Cheat Lake exit off I-68
            P.O. Box 879
            Morgantown, WV  26507-0879
Telephone:  1-800-WV-GEOLOgy (1-800-984-3656) or 304-594-2331
      FAX:  304-594-2575
    Hours:  8:00 a.m. - 5:00 p.m. EST, Monday - Friday

Permission to reproduce this material is granted if acknowledgment is given to the West Virginia Geological and Economic Survey.