Heavy Metal Toxicity of Fly Ash Exposed to Acidic Environments
Keywords:
Fly ash, Heavy metals, Leaching, Toxicity, Acidic environmentAbstract
Fly ash is an industrial solid waste product, produced in huge quantity from industries comprising coal combustion units, especially thermal power plants. Improper Fly ash disposal practices results in severe-long-term environmental problems. The conveying disposal practice of Fly ash involves carrying with water from point of generation to holding ponds or lagoons, heaping and trucking, utilization in cement or concrete making and rest (about 40 percent) fraction is openly dumped into environment as landfill or else. During these practices, Fly ash disperses through all environmental segments and exposed to varying environmental conditions causing prolonged exposure, leaching and accumulation of many toxic metals in biosphere food chain. Comparatively, acidic environment favors more metal leaching, enhance the associated risks and become a great concern. The present study proceeded to evaluate the probable heavy metal toxicity caused by exposing Fly ash to various acids of different concentration and contact time. Metals showed varying degree of leachability from Fly ash exposed to different acid. However, the prominent order of leaching was found as in sequence of Cr > Cu> Pb > Co> Cd. The paper also describes involved possible toxic effects of metals leached from Fly ash exposed to acidic environments.
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