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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. 7, 2014, pp. 199-2008
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Bioline Code: st14195
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. 7, 2014, pp. 199-2008
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Solvent–water extraction method for the evaluation of polycyclic aromatic hydrocarbons bioavailability in coal–tar-contaminated soils
Lee, P.H.; Chao, K.P. & Ong, S.K.
Abstract
A solvent–water extraction method was proposed
as an assessment tool to estimate the bioavailability
of polycyclic aromatic hydrocarbons in coal–tar-contaminated
soils. The approach taken was to measure the percent
of polycyclic aromatic hydrocarbons extracted by a solvent–
water mixture and comparing the results with the
percent of polycyclic aromatic hydrocarbons degraded in a
soil slurry reactor. Five soil samples from three former
manufactured gas plant sites and a coal–tar disposal site
which were operated between 1880 and 1947, and 1945
and 1950, respectively, in Iowa, USA were used in this
study. Extraction experiments were conducted using acetone–
water or ethanol–water mixtures with solvent volume
fractions ranging from 1.0 to 0.4 (v/v). The percent of
polycyclic aromatic hydrocarbons extracted from the various
soils decreased as the volume fraction of the solvent in
the solvent–water mixture was reduced. An acetone–water
mixture of 0.6 was found to be appropriate in correlating
the percent of polycyclic aromatic hydrocarbons degraded
to the percent of polycyclic aromatic hydrocarbons
extracted. For the first correlation, the percent extracted
and the percent biodegraded were modified by using the
molecular weights and log Kow of polycyclic aromatic
hydrocarbons, respectively. For the second correlation, the
equation relating the percent extracted and the percent
biodegraded was modified using soil properties such as
organic carbon content and percent of clay and silt.
Although the experiments were conducted for a limited
number of soils, the extraction method appeared to be a
good starting point in estimating the bioavailability of
polycyclic aromatic hydrocarbons in coal–tar-contaminated
soils.
Keywords
Acetone; Aromatic hydrocarbons; Bioavailability; Solvent
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