ABSTRACT
Coal ashes can be defined as chemical products similar to calcined or fired clay. The three types of ash produced are fly ash, bottom ash, and boiler slag; the amount produced depends on boiler type, characteristics of the coal burned, and/or manner of handling the ash. The abundant amounts produced and the versatility of coal ash make it an ideal substance to take the place of some natural resources; furthermore, its use is supported by the federal government. Coal ashes have many potential uses which include backfill, cement and concrete manufacture, adhesives, wallboard, and soil amelioration/reclamation. When fly ash is applied to soils, concentrations of some of the many elements present in the ash increase. This increase in enrichment ratios requires careful monitoring. Only B becomes toxic to plants, but As, Mo, Se, and others may be potentially toxic to animals consuming the plants grown on the ash-amended soil. Limited research has not shown any detrimental effect on water quality from ash applied to soil. Use of fly ash as a soil amendment has some disadvantages (which may be overcome using proper management), but offers many advantages such as increased plant yield through improved physical and chemical conditions. As a consequence, research needs to be directed not only toward pollution aspects but also toward beneficial uses of ash.
