Arsenic hazards in coal fly ash and its fate in Indian scenario

Abstract

Fly ash (FA) generated as a waste produced from thermal power plants globally has started gaining as a potentially significant anthropogenic source of arsenic (As). In India electricity generation is predominantly dependent upon coal-based thermal power plants and are being producing huge amount of FA. Coal contains many toxic metals, arsenic is one of those, which is significantly toxic for aquatic and terrestrial life including human being. Coal used in Indian thermal power plants is mainly bituminous and sub-bituminous and which on combustion generate over 40% of FA. Generated FA is being disposed to open ash pond in thin slurry form. More than 65,000 acre of land in India is occupied for storage of this massively generated quantity of FA. Dumping of FA in open ash pond causes serious adverse environmental impacts owing to its elevated trace element contents, in particular the As which causes ecological problems. Although, the As problem in our country is not new, in recent years the occurrence of As contamination cases of agricultural soil, ground water as well as human health has resulted a great concern for its mitigation. Very recently India has been charged for being a “dumping hub for As”. Utilization of FA in India is still infancy (more than 38%) as compared to developed countries (more than 70%). In India FA is used particularly in cement production, brick industry, as road base, as amendments in the restoration ecology and forestry. This review emphasized on the concentration of As in FA, its fate and behaviour as hazardous element on human health, environment quality and on mitigation strategies to accomplish environmental management.