Journal of Environmental Biology

Bioavailability evaluation of naphthalene in soil using persulfate

oxidation and ultrasonic extraction method

Author Details

 

Jui-Min Hung

Department of Environmental Engineering, National Chung Shing University, No. 250, Kuo Kuang Road, 

Taichung, Taiwan - 40227, ROC

Hsiang-Chao Liu

Department of Environmental Engineering, National Chung Shing University, No. 250, Kuo Kuang Road, 

Taichung, Taiwan - 40227, ROC

Ching-Shyung Hwu

(Corresponding author)

Department of Environmental Engineering, Hung Kuang University, No. 34, Chung Chie Rd., Sha Lu,

Taichung, Taiwan - 43302, ROC

e-mail: cshwu@sunrise.hk.edu.tw

Chih-Hsing

Department of Environmental Engineering, National Chung Shing University, No. 250, Kuo Kuang Road, 

Taichung, Taiwan - 40227, ROC

Tsao Hung-Yu Lai

Department of Post-Modern Agriculture, MingDao University,  No.369, Wenhua Rd., Peetow, Changhua,

Taiwan - 52345, ROC

Chih-Jen Lu

Department of Environmental Engineering, National Chung Shing University, No. 250, Kuo Kuang Road, 

Taichung, Taiwan - 40227, ROC

 

Publication Data

Paper received:

22 May 2009

 

Revised received:

05 May 2010

 

Accepted:

01 June 2010

 

Abstract

Bioavailability is defined as the fraction of a soil contaminant readily available for microbial degradation and for naphthalene it could be estimated by conventional exhaustive extraction methods. In this study, a novel method that employed persulfate oxidation in combination with ultrasonic extraction (POUSE) was developed. Three parameters, temperature, duration of persulfate oxidation, and the ratio of persulfate to soil organic matter (S₂O₈^2-/SOM; g g^-1), were investigated to obtain an optimum operating conditions. Under the condition, naphthalene bioavailability estimated by the POUSE method was verified and compared with other three exhaustive methods i.e. sonicator, supercritical fluid extraction (SFE), and soxhlet extraction (SE). When the S₂O₈^2-/SOM ratio was controlled at 11.6 g g^-1, the optimum operating conditions of the POUSE method were 70^oC and 3 hr, for the temperature and duration. Under these conditions, the residual naphthalene concentrations were correlated well with the residual naphthalene concentrations for both the cases of freshly spiked and aged soils. By contrast, the sonicator, SFE, and the SE overestimated the naphthalene bioavailability since these three methods extracted naphthalene much more than that of biodegradation test. These results demonstrated that the POUSE could estimate more precisely the naphthalene bioavailability.

 

Key words

Naphthalene, Soil bioavailability, Bioremediation, Persulfate oxidation, Ultrasonic extraction

 

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