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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 11, No. 6, 2014, pp. 1601-1610
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Bioline Code: st14156
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 11, No. 6, 2014, pp. 1601-1610
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Assessing bioaccessible fractions of arsenic, chromium, lead, selenium and zinc in coal fly ashes
Lokeshappa, B.; Dikshit, A.K.; Luo, Y.; Hutchinson, T.J. & Giammar, D.E.
Abstract
The utility of a physiologically based extraction
test for evaluating the bioaccessibility of metals from
fly ash in the human gastrointestinal system was evaluated
in the present research. Calcium-rich and silica-rich fly
ashes collected from eight power plants in India and United
States of America were assessed for bioaccessibility for
arsenic, chromium, lead, selenium and zinc. The results
from the physiologically based extraction test were compared
with those from a sequential extraction procedure
that is often applied to solid wastes. Based on the physiologically
based extraction test results, more than 40 % of
the arsenic was found to be bioaccessible for all the ashes
while selenium was very accessible for the calcium-rich
ashes. Lead was found to be insignificantly bioaccessible
in calcium-rich as well as silica-rich fly ashes. The
mobilization of metals in the first three steps of the
sequential extraction procedure was similar to the mobilization
in the physiologically based extraction test for
selenium for all ashes and for arsenic and chromium for
most ashes, but the sequential extraction procedure mobilized
more zinc than did the physiologically based
extraction test. These results indicate that while sequential
extraction procedures can provide good estimates of the
bioaccessibility of many elements, extraction tests that
more closely simulate physiological conditions can provide
more accurate measures of bioaccessible concentrations of
metals.
Keywords
Bioaccessibility; Coal fly ash; Leaching; Metals; Physiologically based extraction; Sequential extraction procedure
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