Extractability of dioxins from soil: II. Effects of acid or alkaline pretreatment on the extractability of dioxin homologues from soil samples |
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Authors: | Hiroaki Otaka Miho Shinomiya Takashi Amagai |
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Institution: | 1. National Environmental Research and Training Institute , Ministry of the Environment , 3-3 Namiki, Tokorozawa-shi, Saitama 359-0042, Japan hiroaki_otaka@env.go.jp;3. National Environmental Research and Training Institute , Ministry of the Environment , 3-3 Namiki, Tokorozawa-shi, Saitama 359-0042, Japan;4. Institute for Environmental Sciences , University of Shizuoka , 52-1 Yada, Shizuoka-shi, Shizuoka 422-8526, Japan |
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Abstract: | The effects of sample pretreatment on the extractability of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (CoPCBs) from three suburban soil samples were evaluated. The samples were treated with 0.1?M HCl or 0.1?M NaOH and extracted by pressurized liquid extraction (PLE) with toluene. In addition, untreated soil samples were subjected to PLE with acetone. The extractability values were compared to values obtained by toluene extraction without pretreatment. Alkaline pretreatment increased the extractability of higher-chlorinated CDDs (HiCDDs), whereas acid pretreatment slightly decreased their extractability. No change in extractability was observed for higher-chlorinated CDFs under any conditions. The extractability of lower-chlorinated CDD/Fs (LoCDD/Fs) and CoPCBs was increased only by acetone extraction. PCDD/F homologue profiles in soil humic acid fractions and those in dead leaves, a major raw material of soil humus, were also determined. These results suggest that the variations in the extractability of dioxin homologues are due mainly to variations in their physical state in the soil, especially their interactions with soil humus. |
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Keywords: | Sample pretreatment Extractability Dioxins Soil Physical state Humus |
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