Leaching characteristics of a high-calcium fly ash as a function of pH: A potential source of selenium toxicity

Applied Geochemistry
By: , and 

Links

Abstract

Using a modified extraction procedure, the effect of pH on the leaching of selected elements from Ca-rich (Type C) power plant fly ash was studied. Continuous additions of acetic acid were used to maintain pH values of fly ash slurries at 4.0, 6.0 and 8.0 for 24 h and an additional set was leached at its natural pH (average 11.8) value. Analyses for Se, As, Ca, Cd, Cr, Fe, Na and Pb showed that the highest concentrations occur in the leachate at pH 4.0 and decline with increasing pH. Concentrations of Cr and Fe increased slightly between neutral and high pH. Arsenic, Cd, Cr, Pb and Se concentrations exceeded the Environmental Protection Agency's toxicity criteria at pH 4.0. Selenium was above its toxicity level at pH values near 7 but the other elements were below their respective toxicity levels near neutral pH. Because recent studies show adverse effects of Se on aquatic life at far lower concentrations than the current Environmental Protection Agency's standard, high-Ca, power plant fly ashes represent a potentially hazardous pollutant to surface and subsurface waters.

Publication type Article
Publication Subtype Journal Article
Title Leaching characteristics of a high-calcium fly ash as a function of pH: A potential source of selenium toxicity
Series title Applied Geochemistry
DOI 10.1016/0883-2927(88)90092-3
Volume 3
Issue 6
Year Published 1988
Language English
Publisher Elsevier
Description 8 p.
First page 601
Last page 608
Google Analytic Metrics Metrics page
Additional publication details