Soil Contamination and Crop Response to Fly Ash and Effluent Discharge from Coal-Based Thermal Power Plants

Abstract Thermal power plants (CFTPPs) are a major production source of electricity in a large number as well as the developing countries, and their environmental impact is becoming a topic of concern as a result of the fly ash and effluent release of the wastewater. These by-products have heavy metals, soluble salts, and organic residues that change soil physicochemical characteristics, interfere with microbial diversity, and influence crop production. This paper is a review of the recent literature (2018-2025) assessing the synergistic effects of fly ash and discharge effluents on soil quality, microbial ecology, and crop growth with the view of informing sustainable agricultural activities in the impacted areas. The results indicate that fly ash has effects of changing the soil PH, electrical conductivity, nutrient availability and cation exchange capacity whereas effluent irrigation enhances the heavy metal content, salinity and toxicity. Prolonged exposure lowers the microbial diversity and enzyme activities such as dehydrogenase and urease which are important signs of soil health. These altered in microbes interfere with the cycling of nutrients. The effect of pollution on crops is unpredictable, controlled fly ash amendments may enhance germination and productivity by providing necessary nutrients and stabilizing the soil texture but chronic exposure will almost always lead to poor growth, low productivity and accumulation of heavy metals in edible portions, which pose serious food safety issues. The review highlights the necessity of safe specifications of fly ash use, enhanced treatment of effluents, and the incorporation of microbial mediated remediation measures to rejuvenate the health of the soil and also offers an integrative framework in comprehending and managing the ecological foot print of thermal power generation that uses coal, thus empowering sustainable agriculture and environmental protection in energy dependent areas.