title: Bioavailability evaluation of naphthalene in soil using persulfate oxidation and ultrasonic extraction method.
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 (2S,082 /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 S2,O(8)2-/SOM ratio was controlled at 11.6 g g-1, the optimum operating conditions of the POUSE method were 70 degreesC 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.
authors.affiliation: Department of Environmental Engineering, National Chung Shing University, No. 250, Kuo Kuang Road, Taichung, Taiwan - 40227, ROC.
authors.forename: Jui-Min
authors.initials: JM
authors.lastname: Hung
authors.forename: Hsiang-Chao
authors.initials: HC
authors.lastname: Liu
authors.forename: Ching-Shyung
authors.initials: CS
authors.lastname: Hwu
authors.lastname: Chih-Hsing
authors.forename: Tsao Hung-Yu
authors.initials: TH
authors.lastname: Lai
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Lu
mesh_terms: D001673:Biodegradation, Environmental; D005591:Chemical Fractionation / Q000379:methods*; D009281:Naphthalenes / Q000378:metabolism*; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000378:metabolism*; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D009281:Naphthalenes; D012987:Soil; D012989:Soil Pollutants; C031721:naphthalene