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The leachability and chemical speciation of selected trace elements in fly ash from coal combustion and refuse incineration.

Authors
  • Wadge, A
  • Hutton, M
Type
Published Article
Journal
Environmental Pollution
Publisher
Elsevier
Publication Date
Jan 01, 1987
Volume
48
Issue
2
Pages
85–99
Identifiers
PMID: 15092689
Source
Medline
License
Unknown

Abstract

A laboratory leaching test has been used to predict the potential mobility of As, Se, Pb and Cd in landfilled fly ash produced by coal combustion and refuse incineration. These waste residues also formed the basis of a speciation study in which the valency states of As and Se and the chemical forms of Pb and Cd have been determined. Selenium displayed the greatest leachability in each ash type, despite being present at relatively low concentrations in both materials. Substantial amounts of other trace elements were also leached, particularly Pb and Cd from refuse ash and As from coal ash. Chemical associations of Pb and Cd were examined by a sequential extraction procedure. In coal fly ash, both elements were mostly present in the residual fraction, while in refuse ash these elements were mainly associated with the exchangeable fraction. Water-soluble extracts of coal fly ash contained As exclusively as As(V); high background interference prevented the detection of water-soluble As in refuse ash. Selenium was present largely as Se(IV) in aqueous extracts of both ash types. The value of speciation techniques and leaching tests as predictors of environmental behaviour is discussed in conjunction with results of routine trace element determinations and plant uptake studies.

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