Effects of power plant coal pile and coal waste runoff and leachate on aquatic biota: an overview with research recommendations.

Abstract

Coal, the major energy reserve in the US, accounts for nearly 80% of the known attainable resources and 74.0% of the ultimate recoverable reserves.’ In 1975 the US. produced 19% of the world supply of bituminous and lignite coals with approximately 73% of this coal consumed by the electric utilities.2 Gordon3 has reported that the use of coal for electric power generation will likely increase in future years in order to achieve our national goal of energy independence. The increased use of coal will result in the production of large quantities of fly ash, scrubber sludge, and other coal waste disposal products. Storage of this coal waste in disposal piles along with coal storage piles causes potential problems for aquatic biota that may be subjected to runoff and leachate from these piles entering aquatic systems. It has been well documented that runoff and leachate from coal piles and waste disposal piles contain a complex mixture of metals, salts, and organics. During independent studies various investigators have reported that ar~enic,~ cadrni~m,~ and selenium6 are important components of coal pile and coal waste effluents that could cause potential biological problems in the aquatic environment near coal-fired power plants. For this reason, we have selected these metals for the focus of this review. Recently the US. Environmental Protection Agency reviewed the toxicity literature on these metals.’-’ Therefore, this review was not intended to duplicate those reviews, but rather to present studies addressing actual concepts regarding the occurrence and toxicity of these metals relevant to coal pile and coal waste disposal effluents. The emphasis of the review was (1) to evaluate studies regarding the occurrence and toxicity of the above metals associated with coal effluent and (2) to identify areas not adequately addressed in the existing data. Data for both fresh and tidal fresh/oligohaline invertebrates and fish were evaluated. An attempt was initially made to determine the combined interactive effects of arsenic, cadmium, and selenium. However, it became evident from a preliminary review of the literature that suitable data and models were not available to predict the collective toxicity of these metals based on the individual toxicity of each Therefore, we reviewed the toxic effects of each metal separately. The following terms and subsequent definitions are used throughout the paper: bio