Aluminium in coal fly ash (FA), in plants grown on FA, and in the leachates from FA.

Abstract

Two coal fly ashes (FA), one from Montana semi-bituminous coal and another from North Dakota lignite alone or in combination with bottom ash (BA) from Montana semi-bituminous coal were tested as plant growth media for the following plant species: barley (Hordeum vulgare), oats (Avena sativa), rye (Secale cereale), wheat (Triticum aestivum), regreen; a hybrid between wheatgrass (Agropyron cristatum) and winter wheat (Triticum aestivum), and triticale; a hybrid between wheat (Triticum aestivum) and rye (Secale cereale). The concentration of Al, in coal ashes and in plant seedlings was determined using Inducted Coupled Plasma Spectrophotometry (ICP). All tested plant species germinated and grow in FA and/or FA + BA containing media. These data demonstrate that tested plants can grow on media consisting of coal ash, and therefore these plants can be used to cover FA or BA residue piles. In summary, the presence of sphagnum peat moss and soil in coal ash based plant growth media expressed ameliorative role by reducing the presence of Al in plant growth media and in plant seedlings grown on these media, but it did not translate into the decrease of the presence of Al in the leachate from these media. Elevated concentrations of Al in the leachate may cause some environmental health concerns and require further investigations.