Preliminary study on biodegradation and detoxification of dioxins

为了修复二恶英污染的土壤，研究了白腐菌的生物降解、化学分解和解毒作用。生物降解：用低毒的2,7 - dcdd（二氯化物）检测了几种白腐菌的分解活性。结果表明，香菇、灰树花和金针菇培养2周后，二恶英分解率为30-40%（氧气100%，木质素添加量20mg/10ml）。这些活性几乎相当于白腐菌，黄孢Phanerochaete chrysosporium（有毒且分解活性已被证实）。发现熟悉的蘑菇具有分解二恶英的活性，说明了未来修复厂利用蘑菇的可能性。化学分解：对各种试剂进行了分解活性筛选。结果表明，Fe^<3+>-h_2O_2混合试剂对DCDD具有较强的活性。在70℃条件下，Fe^<3+> (8mM) - H_2O_2(1%)， DCDD几乎完全分解15 min。该混合试剂对模型土壤中DCDD的分解效果较好。这种化学分解法因其性价比高，且不会对环境造成二次污染，被认为是一种实用的修复方法。解毒：我们发现，通过蒸汽蒸馏法可以很好地去除土壤中的DCDD，即使在实际污染的土壤中也是有效的

For the purpose of the remediation of the dioxin-polluted soil, biodegradations using white-rot fungi, chemical decompositions, and detoxification were investigated. The results were summarized as follows :Biodegradation : The decomposition activity of several white-rot fungi was examined using low-toxic 2, 7-DCDD (dichloride). As the resutl, there was the decompostion of 30-40% dioxin in the culture (oxygen 100%, lignin addition 20mg/10ml) for 2 weeks in Lentinus edodes, Grifola frondosa, and Flammulina velutipes. These activities were almost equivalent to that of a white-rot fungus, Phanerochaete chrysosporium (noxious and the decomposition activity has already been proven). The familiar mushrooms were found to have the dioxin decomposition activity, indicating the possibility of the remediation plant using hte mushrooms in the futureChemical decomposition : The screening of pinment decomposition activity was carried out for various reagents. As the result, Fe^<3+>-h_2O_2 mixed reagent had a strong activity for DCDD. Under the condition of 70℃, Fe^<3+> (8mM) - H_2O_2(1%), DCDD was almost perfectly decomposed for 15 min. Also, this mixed reagent was effective for DCDD decomposition in hte model soil. This chemical decomposition method is greatly expected as a practical remediation method because of its cost performance and no secondary contamination ot the environmentDetoxification : We found that DCDD in the soil could perfectly remove by a steam distillation, and it was effective even in an actual polluted soil