220 BIRGE 



With the increasing dependence on coal as a national energy source, 

 there is a serious need to investigate further the effects of coal 

 production and use on environmental health. Numerous recent 

 studies emphasize the extent to which coal utilization has grov^n 

 beyond our ability to identify fully the hazardous trace elements in 

 coal, quantify their release rates into the environment, and define 

 their biological and health-related effects (Ayer, 1974; Yavorsky and 

 Akhtar, 1974; Babu, 1975; Vaughan et al., 1975). Approximately 

 two-thirds of the over 60 elements that occur in coal have been 

 detected as environmental pollutants (Vitez, 1976). Although toxico- 

 logical data are largely incomplete, most of the elements found in 

 coal and other fossil fuels are known to have at least some toxic 

 effects on animal species (National Academy of Sciences— National 

 Academy of Engineering, Committee, 1973; Smith, Ferguson, and 

 Carlson, 1975; Vitez, 1976). 



The annual combustion of 600 million tons of coal constitutes 

 the major source of environmental contamination v^th coal trace 

 elements (Abel and Rancitelli, 1975; Bolton et al., 1975; Sheibley, 

 1975). The main sources of water pollution are power plants, which 

 dispose of more than 50 million tons/year of bottom ash and 

 precipitated fly ash (Rubin and McMichael, 1974; Chu, Nicholas, and 

 Ruane, 1975). Large quantities of water are used in sluicing ash 

 residues to settling ponds, and pond effluents contain toxic metals 

 that affect the quality of receiving waters (Theis, 1975; Hildebrand, 

 Cushman, and Carter, 1976). For each 1000-MW capacity, sluicing- 

 water requirements for Tennessee Valley Authority (TVA) power 

 stations average 11.5 million gal/day or 4.2 billion gal/year (Environ- 

 mental Protection Agency, 1974; Chu, Nicholas, and Ruane, 1975). 

 Current projections indicate that the rate of coal combustion will 

 double by the mid 1980s (Vaughan et al., 1975). Therefore, a better 

 understanding of the aquatic toxicology of coal-derived contami- 

 nants is essential if we are to maximize coal use and also institute 

 safeguards necessary to maintain reasonable and proper environ- 

 mental health. 



In this study, aquatic bioassays were performed to establish a 

 comparative toxicological ranking for 22 coal elements, identify 

 those which may be particularly hazardous to aquatic ecosystems, 

 and provide quantitative data for use in further evaluations of 

 environmental standards and pollution-abatement technology. In 

 addition, a bench-scale settling pond was developed to simulate 

 fly-ash effluents and to investigate the aqueous leaching of toxic 

 elements. Continuous flow embryo— larval bioassays were used for in 

 situ monitoring of ash effluents to provide direct toxicological 

 evaluations on complex suites of trace elements. 



