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Arsenic in Twelve Coal Beds/Zones in the Northern and Central Appalachian Basin Coal Regions
Poster

By Linda J. Bragg, Sandra G. Neuzil, Leslie F. Ruppert, and Susan J. Tewalt

U.S. Geological Survey. Reston, VA 20192

Arsenic is listed as a potential HAP (hazardous air pollutant) in the 1990 Clean Air Act Amendments (U.S. Statutes at Large, 1990). Therefore, arsenic was one of the trace-elements characterized in the top-producing coal beds and coal zones that were studied in the recently completed northern and central Appalachian Basin coal regions assessment (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). Six Pennsylvanian coal beds/zones were digitally assessed for coal quality, and six other coal zones were summarized from published data (quality). The stratigraphic sequence of the 12 coal beds/zones discussed in this abstract is shown in figure 1. Arsenic concentrations in these coal beds/zones were examined both stratigraphically and geographically for trends.

Generalized stratigraphic column showing stratigraphic positions of the 12 coal beds/zones discussed in the northern and central Appalachian Basin coal region   Figure 1. Generalized stratigraphic column showing stratigraphic positions of the 12 coal beds/zones discussed in the northern and central Appalachian Basin coal region. In the recently completed northern and central Appalachian Basin coal regions assessment, the eight Middle Pennsylvanian Pottsville coals are designated as coal zones, while the remaining four coals are considered as coal beds.
[* denotes digitally assessed coal beds or zones]


Mean, range, and standard deviation for arsenic concentrations in in-ground complete channel and core samples of the 12 coal beds/zones are summarized in table 1. Data are reported on either as-received or remnant moisture bases (Bragg and others, 1998), but, because these coals are bituminous, their moisture content difference is small (less than 5 percent, which is probably within the experimental error of the analysis and well within the standard deviation of the samples).

In the accompanying figures 2-13, arsenic values for 12 coal beds/zones are shown as point data (part A) and as county means (part B). All arsenic values (n=1,343) for the 12 coal beds/zones were classified into five data categories, or quintiles, each representing 20 percent of the point data values. Additional data (n=36) located only to county accuracy were included to generate the county means. Mean arsenic values for each county were calculated for each of the coal beds/zones, and then all county means (for all coal beds/zones) were grouped for classification into five data categories, or quintiles, each representing 20 percent of the county mean data values. Because the quintile intervals are based on different sets of data (point data versus county means), the ranges of arsenic concentrations will be different for both data sets. For the six digitally assessed coal beds, the county means are shown within the digital outcrop in part B of each figure. For the other coal beds, the county means are shown within the county boundaries. (Note: samples from the State of Tennessee were excluded from this study. Samples were also excluded from the study when data values for ash yield, sulfur content, gross calorific value, and antimony, beryllium, cadmium, chlorine, chromium, cobalt, lead, manganese, nickel, selenium, arsenic, and mercury contents were three standard deviations above the population mean.)

County means may be based on as few as two samples. The county parts of each figure are intended for graphical regional comparisons only. Point sample part and county part legends are included separately for easier reading.

The mean arsenic concentration for the 1,343 samples from these 12 coal bed/zones is 17 (±23) ppm (table 2). For the three coal beds from the northern Appalachian Basin coal region (Pittsburgh, Upper Freeport, and Lower Kittanning), the mean arsenic concentration is 22 (± 22) ppm with a range of 0.18 to 130 ppm. The nine remaining beds/zones are located in the central Appalachian Basin coal region and have a mean arsenic concentration of 14 (± 23) pm with a range of 0.075 to 280 ppm arsenic. Mean concentration of arsenic in each of the 12 coal beds/zones is below the mean arsenic concentration (35 ppm) in the Appalachian Basin (Finkelman and others, 1994). However, this mean concentration for the Appalachian Basin does not exclude any high outlier values and includes samples from many more coal beds and zones throughout the northern, central, and southern Appalachian Basin coal regions. Three of the coal beds/zones have mean arsenic concentrations that are greater than the mean for U.S. coal (24 ± 5.5 ppm) (Finkelman, 1993). These are the Upper Freeport (34 ± 25 ppm) coal bed and the Williamson/Amburgy (28 ± 30 ppm) and Upper Elkhorn Nos. 1 and 2/Powellton coal zones (27 ± 47 ppm). However, because arsenic is primarily associated with pyrite in coal (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001), and because most mined coal of the northern and central Appalachian Basin is washed or cleaned prior to combustion (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001), it is likely that atmospheric arsenic emissions generated from combustion of northern and central Appalachian Basin coal will be considerably less than would be predicted from the 17 (±23) ppm mean in-ground arsenic concentration for these 12 coal bed/zones (table 2). In addition, as this paper shows, much of the coal currently mined in the Appalachian Basin coal regions is lower in arsenic content than the mean for the Appalachian Basin (35 ppm). The available data do not appear to indicate any significant stratigraphic or regional trends in arsenic concentrations over the northern and central Appalachian Basin coal regions.

Tables 3, 4, 5, 6, 7, and 8 contain the statistics generated for the county parts (part B) in figures 2 through 13. The coal beds/zones are listed in stratigraphic sequence in the tables, which are organized by State and county.

Arsenic content of the Pittsburgh coal bed in Pennsylvania, West Virginia, Ohio, and Maryland   Figure 2. Arsenic content (in parts per million [ppm], as-received whole-coal basis) of the Pittsburgh coal bed in Pennsylvania, West Virginia, Ohio, and Maryland. Part A shows arsenic contents of the 140 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 140 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.33 to 61 ppm with a mean value of 12±13 ppm (table 1).

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Arsenic content of the Upper Freeport coal bed in Pennsylvania, West Virginia, Ohio, and Maryland   Figure 3. Arsenic content (parts per million [ppm], as-received whole-coal basis) of the Upper Freeport coal bed in Pennsylvania, West Virginia, Ohio, and Maryland. Part A shows arsenic contents of the 224 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 250 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.72 to 130 ppm with a mean value of 34±25 ppm (table 1).

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Arsenic content of the Lower Kittanning coal bed in Pennsylvania, West Virginia, Ohio, and Maryland   Figure 4. Arsenic content (parts per million [ppm], as-received whole-coal basis) of the Lower Kittanning coal bed in Pennsylvania, West Virginia, Ohio, and Maryland. Part A shows arsenic contents of the 184 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 190 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.13 to 130 ppm with a mean value of 19±20 ppm (table 1).

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Arsenic content of the No. 5 Block coal zone in Kentucky and West Virginia   Figure 5. Arsenic content (parts per million [ppm], remnant moisture, whole-coal basis] of the No. 5 Block coal zone in Kentucky and West Virginia. Part A shows arsenic contents of the 88 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 88 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.75 to 70 ppm with a mean value of 11±14 ppm (table 1).

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Arsenic content of the Stockton/Coalburg coal zone in Kentucky and West Virginia   Figure 6. Arsenic content (parts per million [ppm], remnant moisture, whole-coal basis) of the Stockton and Coalburg coal zone in Kentucky and West Virginia. Part A shows arsenic contents of the 193 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 193 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.40 to 79 ppm with a mean value of 11±14 ppm (table 1).

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Arsenic content of the Winifrede/Hazard coal zone in Kentucky and West Virginia   Figure 7. Arsenic content (parts per million [ppm], remnant moisture, whole-coal basis) of the Winifrede/Hazard coal zone in Kentucky and West Virginia. Part A shows arsenic contents of the 81 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 81 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.40 to 58 ppm with a mean value of 8.7±11 ppm (table 1).

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Arsenic content of the Fire Clay coal zone in Kentucky, Virginia and West Virginia   Figure 8. Arsenic content [parts per million (ppm), remnant moisture, whole-coal basis] of the Fire Clay coal zone in Kentucky, Virginia and West Virginia. Part A shows arsenic contents of the 36 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 39 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones.. Arsenic contents range from 0.70 to 53 ppm with a mean value of 11±13 ppm (table 1).

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Arsenic content of the Williamson/Amburgy coal zone in Kentucky and Virginia   Figure 9. Arsenic content [parts per million (ppm), remnant moisture, whole-coal basis] of the Williamson/Amburgy coal zone in Kentucky and Virginia. Part A shows arsenic contents of the 37 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 37 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.61 to 120 ppm with a mean value of 28±30 ppm (table 1).

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Arsenic content of the Campbell Creek/Upper Elkhorn No. 3 coal zone in Kentucky, Virginia and West Virginia   Figure 10. Arsenic content (parts per million [ppm], remnant moisture, whole-coal basis) of the Campbell Creek/Upper Elkhorn No. 3 coal zone in Kentucky, Virginia and West Virginia. Part A shows arsenic contents of the 136 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 136 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.85 to 170 ppm with a mean value of 14±19 ppm (table 1).

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Arsenic content of the Upper Elkhorn Nos. 1 and 2/Powellton coal zone in Kentucky, Virginia and West Virginia   Figure 11. Arsenic content (parts per million [ppm], remnant moisture, whole-coal basis) of the Upper Elkhorn Nos. 1 and 2/Powellton coal zone in Kentucky, Virginia and West Virginia. Part A shows arsenic contents of the 104 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 104 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.80 to 280 ppm with a mean value of 27±47 ppm (table 1).

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Arsenic content of the Pond Creek coal zone in Kentucky, Virginia and West Virginia   Figure 12. Arsenic content (parts per million [ppm], as-received, whole-coal basis) of the Pond Creek coal zone in Kentucky, Virginia and West Virginia. Part A shows arsenic contents of the 88 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 88 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.075 to 74 ppm with a mean value of 9.9±14 ppm (table 1).

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Arsenic content of the Pocahontas No. 3 coal bed in Virginia and West Virginia   Figure 13. Arsenic content (parts per million [ppm], as-received, whole-coal basis) of the Pocahontas No. 3 coal bed in Virginia and West Virginia. Part A shows arsenic contents of the 32 geochemical samples for which records are publicly available and located by latitude and longitude. The values are classified into five categories, each representing 20 percent of the 1,343 point data values representing 12 coal beds/zones. Part B shows county averages for arsenic content using all 33 records in the geochemical database (Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001). These values are classified into five categories, each representing 20 percent of the 278 county mean vales (shown in tables 3-8) representing the 12 coal beds/zones. Arsenic contents range from 0.30 to 35 ppm with a mean value of 7.1±8.1 ppm (table 1).

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REFERENCES

Bragg, L.J., Oman, J.K., Tewalt, S.J., Oman, C.L., Rega, N.H., Washington, P.M., and Finkelman, R.B., 1998, The U.S. Geological Survey Coal Quality (COALQUAL) Database: Version 2.0: U.S. Geological Survey Open-File Report 97-134, CD-ROM.

Finkelman, R.B., 1993, Trace and minor elements in coal, in Engel, M.H., and Macko, S.A., eds., Organic geochemistry: New York, Plenum Press, p. 593-607.

Finkelman, R.B., Oman, C.L., Bragg, L.J., and Tewalt, S.J., 1994, The U.S. Geological Survey Coal Quality Data Base: U.S. Geological Survey Open-File Report 94-177, 42 p.

Northern and Central Appalachian Basin Coal Regions Assessment Team, 2001, Resource assessment of selected coal beds and zones in the northern and central Appalachian Basin coal regions: U.S. Geological Survey Professional Paper 1625-C, CD-ROM.

U.S. Statutes at Large, 1990, Public Law 101-549, Provisions for attainment and maintenance of national ambient air quality standards: 101st Congress, 2nd Session, 104, pt. 4, p. 2353-3358.

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