h i g h l i g h t sPetrological and biological aspects of Indian coal-derived fly ash are addressed. The petrology of coal-derived fly and bottom ashes is dominated by glass and spinel. The deposition of coal fly ash over the plants leaves reduces the photosynthesis rate. Coal-derived fly ash affects the stomatal conductance in plants leaves. g r a p h i c a l a b s t r a c t Keywords:Indian coal fly ash Petrology of fly ash Biology of fly ash Power plant Photosynthesis a b s t r a c t India has about a tenth of the world's coal reserves, much of it with high mineral content. These coals produce a large amount of fly ash, which can affect human health and environmental quality aspects during utilization. In this paper, the petrological and biological aspects of some industrially important Indian coal fly ash (CFA) from a coal-based captive power plant are addressed. The petrology of the CFAs is also studied for the samples collected in different times. The study has revealed that the CFAs contain mainly glass fragments, spinel, quartz, and other minerals in lesser quantities. Fly ash carbons were present as chars, possibly from the incomplete combustion of the coals (bituminous and/or subbituminous) used in the power plant. The deposition of CFAs over the leaves of different plant species reduces the photosynthesis rate by about 95% within a period of 2 h. The CFAs also show minor effects to some test microbes. This investigation will be useful in assessment of the environmental impact of a coal-based power plant.

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