Plant Growth and Trace‐Element Uptake on Acidic Coal Refuse Amended with Lime or Fly Ash

Abstract

Two commonly used revegetation species, ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) and ‘Lincoln’ smooth brome (Bromus inermis Leyss.), were grown for 60 days in pots containing coarse coal mine refuse (referred to as gob, pH = 3.5) amended with either lime or alkaline powerplant fly ash. Both species were also grown in pots containing a silt loam surface soil as a control. Morphological growth parameters were measured over time; dry weights and shoot/root ratios were determined at harvest. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in the plant shoots were determined by atomic absorption spectrophotometry. Plant growth of both species was not as good on either lime‐ or fly ash‐amended gob as it was on surface soil; however, more vigorous growth occurred on lime‐amended gob than on fly ash‐amended gob. Significant differences (p <0.05) in the tissue concentrations of Cd, Co, Fe, Hg, Mn, Pb, V, and Zn were found among the plants grown on the three substrates. Except for Hg and Pb, these elements were higher in plants grown on at least one of the amended‐gob substrates than in plants grown on surface soil. Significant substrate differences were not observed for Al, As, Cr, Cu, Ni, and Se. The tissue concentrations of some elements—notably Al, Cu, Fe, Mn, V, and Zn—were high enough in plants from one or more of tbe substrates to either approach or exceed concentrations which have been reported to be associated with toxic effects in some plant species.

The Indian perspective of utilizing fly ash in phytoremediation, phytomanagement and biomass production

“…Addition of alkaline FA to wasteland and mine spoils increases the pH, decreases soil bulk density, increases water-holding capacity and reduces compaction (Capp, 1978;Jastrow et al, 1981;Fail, 1987). Saxena and Asokan (1998) observed in a field experiment that wasteland (agriculturally unproductive) soil amended with 25% (w/w) FA resulted in a 40% increase in plant growth.…”

Speciation of some heavy metals in coal fly ash

“…Many elements (major and trace) are preferentially incorporated or remain associated with fly ash particles during coal combustion (Page et al, 1979;Roy et al, 1981). Chemically, fly ash is composed of ferro -alumino -silicate minerals containing considerable quantities of Ca, K and Na, along with other trace elements such as Cu, Zn, Mn, Mo, Ni and Se (Jastrow et al, 1981). Co, Cr, Cu and Ni remain associated with the iron oxide fraction and the elements with relatively low mobility (Cr, Cu, Pb and V) show affinity to silicates and glass fraction (Nugteren et al, 2002).…”

The use of coal fly ash in sodic soil reclamation

“…One possible way of using the fly ash is as a sodic soil amendment by increasing the soluble Ca þ2 concentrations in the soil. Though coal fly ash has been used as liming material for acid soils (Jastrow et al, 1981;Hodgson et al, 1982), information regarding its effectiveness as an ameliorant for sodic soils is lacking. The pH range of fly ash has been reported from 4Á5 to 12Á0 (Plank and Martens, 1974;Page et al, 1977).…”