Chemical and toxicological properties of coal fly ash - University of ...

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During the late 1970s shortages of natural gas, fuel oil, and gas01 inedramatically demonstrated the need for t e increased use of coal byelectric utilities. Although predictions vary, the National CoalAssociation forecasts an increase in coal usage from 787 million metrictons in 1976 to approximately 1.5 billion metric tons by 1985. Thecombustion of coal produces solid wastes composed primarily of thenoncombustible mineral matter (ash) present in the coal. Fly ash is thatportion of ash that is small enough, in terms of particle size, to beentrained in the flue gases and carried away from the site of combustion.Of the 67.8 million tons of ash produced in the 1J.S. in 1977, approximately48 million tons was fly ash (Faber, 1979). Ash production may reach 125million tons by 1990 and may increase by a factor of four in the next 20years (Faber, 1979). In Illinois, the three major electric utilitiesgenerated an estimated l,867,OO0 tons of fly ash in 1979 (Roy et al.,1981).The imp1 icat ions of the Resource Conservation and Recovery Act (RCRA) of1976 have focused attention on coal fly ash and its subsequent disposalproblems. The prevalent method of fly ash disposal is by sluicing the ashslurries from the power plants into some type of natural or man-made basinwhere the ash settles. The resulting supernatant may contain potentiallytoxic trace constituents, leached from the fly ash, which could poseproblems to the aquatic ecosystems into which they eventually flow.Several studies assessing the environmental impact of coal fly ash havedealt largely with fly ashes generated from coals from the Appalachianregion (Chu et al., 1978; Furr et al., 1977; Klein et al., 1975; Plank etal., 1975) and from western bituminous, subbituminous, and lignite coals(Elseewi et al., 1980; Mann et al., 1978; Ondov et al., 1979; Swanson etal., 1976).Fly ashes produced by the combustion of coals from the Illinois coal basinhave also been studied (Cox et al., 1978; Davison et a1 ., 1974; Griffin etal., 1980; Linton et al., 1976; Natusch et ale, 1977; Theis and Mirth,1977). However, as indicated in literature reviews by Adriano et al. (1980),Page et al. (1979), and Roy et al. (1981), the physicochemical propertiesof fly ash may vary from plant to plant and even from different boilerswithin a particular plant. Moreover, 1 aboratory leaching and disposal pondstudies of the aqueous chemical interactions with fly ashes generated fromIllinois Basin coals have also produced varying results. Additional workwith Illinois fly ashes is needed in order to assess the possibleenvironmental impacts of coal fly ash disposal.Elevated pH levels of fly ash leachates have been shown to be toxic toaquatic organisms (Cairns et a1 ., 1972; Wasserman et a1 ., 1974). Otherstudies (Birge, 1978; Thompson, 1963) have examined the role of traceelements in the aquatic toxicology of leachates from coal and fly ash.Trace elements leached from fly ash can accumulate in the ti,ssues of fishand fish forage (Cherry et al., 1976; Ryther et al., 1979). Contaminatedfish from cooling lakes or other aquatic ecosystems exposed to fly asheffluent may pose potential health hazards to fishermen.
The overall purpose of this investigation was to provide information thatmay be of assistance in predicting the environmental impacts of coal flyash disposal. Data resulting from this investigation should be useful toutilities, consultants, and state, local, and federal agencies concernedwith fly ash and its disposal.The objectives of the study were to:Review the ecological and health literature concerning fly ash.Assess the variability in terms of chemical composition andaqueous solubility of fly ashes derived from Illinois Basin coals,and compare these fly ashes to those generated from western U.S.coal s.Determine if the extracts generated from fly ash were acutelytoxic to fishes.- Determine if the soluble trace metals in the fly ashextracts were accumul ated by fishes under 1 aboratoryconditions.Nine fly ash samples generated from Illinois Basin coals--predominantly silts (USDA classification)--varied in color from verydark grayish brown (10YR Munsell soil colors) to gray (2.5Y - 5Y). Theaverage specific gravity of the nine samples was about 2.4. Two flyashes generated by the combustion of western U.S. lignite coals werelighter in color (light gray) and had greater specific gravities (about3.05), whereas a western subbituminous coal fly ash had a darker gray(10YR) color and a specific gravity of 2.2.The general mineralogical composition of the Illinois Basin fly asheswas comparable to that of fly ashes generated from eastern 1J.S.bituminous coals, as reported elsewhere. They were essentiallyspherical particles composed of an amorphous alumino-silicate glass,quartz, mu1 1 i te (A16Si 2013), and iron oxides. The subbi tuminouswestern ash was similar in mineralogical composition to the Illinoissamples, except for the presence of calcite in the western ash. The twowestern lignite samples had higher concentrations of some alkalinemetals and matrix sulfur, primarily in the form of anhydrite (CaS04)and pericl ase ( MgD) .Most of the matrix sulfur in all 12 samples existed as sulfatecompounds. The average ratio of sulfate S to sulfide S in the Illinoissamples was about 5:l.The trace constituent concentrations in the samples were highlyvariable, but the Illinois fly ash samples generally had greaterconcentrat ions of (in decreasing order of concentrat ion) Zn , N i , Rb,Cs, Cr, Co, U, Ge, Mo, V, Li, Cd, TI, Sm, Pb, Be, Eu, Tb, Ga, Ce, As,
Page 1 and 2: lllinoiSTATSTAT
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Page 5: TABLESSummary of the origin and gen
Page 9 and 10: steady state conditions in the disp
Page 11 and 12: total carbon determinations were ca
Page 13 and 14: y passing the extract through a col
Page 15 and 16: The GC-MS analyses were performed b
Page 17 and 18: with ultrapure water. The final HCl
Page 19 and 20: Be 3. Wlir~eraiogical composi'tion
Page 21 and 22: Table 6. Trace constituent concentr
Page 23 and 24: Table 7. Fly ash sample classificat
Page 25 and 26: Table 8. Carbon, sulfur, and benzen
Page 27 and 28: Wave number (cm-'Figure 8. Infrared
Page 29 and 30: Figure 12. HPLC chromatogram of the
Page 31 and 32: Figure 16. HPLC chromatogram of the
Page 34 and 35: Table 11. Organic components in the
Page 36 and 37: Figure 21. Gas chromatogram of the
Page 38 and 39: 4.Jrcrm c o mQU"* 'tn U.a-U U O NrO
Page 40 and 41: constituents. The amount of soluble
Page 42 and 43: Table 14. Change in chemical compos
Page 44 and 45: Table 16. Change in chemical compos
Page 46 and 47: Change in chemical composition as a
Page 48 and 49: Figure 26. Changes in the concentra
Page 50 and 51: Table 19. Corytituents in the long-
Page 52 and 53: Table 21. The LC-50 values, amount
Page 54 and 55: Table 23. The range of concentratio
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Table 25. The range of concentratio
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Table 27. The mean initial lengths
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Table 32. The mean final lengths an
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Several of the extrbivalves ( ~ are
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The mean concentrations of various
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1972). Cadmium is a dangerous cumul
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Bl umer, M., 1957, Removal of eleme
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Furr, A. K-, T. F, Parkinson, R. A.
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Murtha, M. J., and G. Burnet, 1979,
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Standard methods for examination of
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