Franzetti Andrea, Di Gennaro Patrizia, Bevilacqua Alessandro, Papacchini Maddalena, Bestetti Giuseppina
Department of Environmental Sciences, University of Milano-Bicocca, p. della Scienza 1, 20126 Milano, Italy.
Chemosphere. 2006 Mar;62(9):1474-80. doi: 10.1016/j.chemosphere.2005.06.009. Epub 2005 Aug 9.
One of the main limitations for a wider application of surfactants in soil remediation is the lack of knowledge about environmental fate and toxicity of surfactant itself especially for in situ application. Sorption behaviour, biodegradability, toxicity of parent compound and its metabolites are important processes that affect environmental fate of surfactants in site remediation applications. Tween 80 (poly(oxyethylene)(20)-sorbitane monooleate) and Aerosol MA+80 (dihexyl sodium sulfosuccinate) are surfactants that have been tested in laboratory and field scale remediation of soil and groundwater. In this work, the sorption and biodegradability of these surfactants were assessed to provide conditions and limitations for their use. The soil used in this experimentation was analysed for organic carbon content, soil bacteria, and size fraction and resulted to be a good model because is characterised by mean values for almost all considered parameters. Tween 80 showed high degree of biodegradability but a high affinity for soil matrix. Results suggest that Tween 80 could find its best application in ex situ solid phase remediation like ex situ bioremediation; its high affinity to soil could limit in situ applications. Biodegradation tests for Aerosol MA+80 show low degree of biodegradability and mineralisation. Biodegradation experiments, coupled with analysis of toxicity, could support the hypothesis that degradation of Aerosol MA+80 is not complete and leads to an accumulation of intermediates with at least the same toxicity of the parental compound. Therefore, aquifer remediation application with Aerosol MA+80 has to be conducted with necessary precautions to avoid product loss and excess surfactant should be flushed from the soil.
表面活性剂在土壤修复中更广泛应用的主要限制之一是缺乏关于表面活性剂本身环境归宿和毒性的知识，特别是对于原位应用。吸附行为、生物降解性、母体化合物及其代谢物的毒性是影响表面活性剂在场地修复应用中环境归宿的重要过程。吐温80（聚（氧乙烯）（20）-山梨醇单油酸酯）和气溶胶MA + 80（磺基琥珀酸二己酯钠）是已在土壤和地下水的实验室和现场规模修复中进行测试的表面活性剂。在这项工作中，评估了这些表面活性剂的吸附和生物降解性，以提供其使用的条件和限制。对本实验中使用的土壤进行了有机碳含量、土壤细菌和粒度分析，结果表明它是一个很好的模型，因为几乎所有考虑参数的平均值都具有代表性。吐温80显示出高度的生物降解性，但对土壤基质具有高亲和力。结果表明，吐温80最适合应用于异位固相修复，如异位生物修复；其对土壤的高亲和力可能会限制原位应用。气溶胶MA + 80的生物降解测试显示出低程度的生物降解性和矿化作用。生物降解实验与毒性分析相结合，可以支持这样的假设，即气溶胶MA + 80的降解不完全，会导致中间体的积累，其毒性至少与母体化合物相同。因此，在使用气溶胶MA + 80进行含水层修复应用时必须采取必要的预防措施，以避免产品损失，并且应从土壤中冲洗掉过量的表面活性剂。
