Szolar Oliver H J, Rost Helmut, Hirmann Doris, Hasinger Marion, Braun Rudolf, Loibner Andreas P
Department of Environmental Biotechnology, Institute for Agrobiotechnology, Konrad Lorenz Strasse 20, 3430 Tulln, Austria.
J Environ Qual. 2004 Jan-Feb;33(1):80-8. doi: 10.2134/jeq2004.8000.
Sequential supercritical fluid (CO2) extraction (SSFE) was applied to eight historically contaminated soils from diverse sources with the aim to elucidate the sorption-desorption behavior of high molecular weight polycyclic aromatic hydrocarbons (PAHs). The method involved five extraction phases applying successively harsher conditions by increasing fluid temperature and density mobilizing target compounds from different soil particle sites. Two groups of soils were identified based on readily desorbing (available) PAH fractions obtained under mildest extraction conditions (e.g., readily desorbing fractions of fluoranthene and pyrene significantly varied between the soils ranging from <10 to >90%). Moreover, extraction behavior strongly correlated with molecular weight revealing decreasing available PAH fractions with increasing weight. Physicochemical soil parameters such as particle size distribution and organic dry mass were found to have no distinct effect on the sorption-desorption behavior of PAHs in the different soils. However, PAH profiles significantly correlated with readily available pollutant fractions; soils with relatively less mobile PAHs had higher proportions of five- and six-ring PAHs and vice versa. Eventually, biodegradability corresponded well with PAH recoveries under the two mildest extraction phases. However, a quantitative relationship was only established for soils with biodegradable PAHs. Out of eight soils, five showed no biodegradation including the four soils with the lowest fraction of readily desorbing PAHs. Only one soil (which was found to be highly toxic to Vibrio fischeri) did not match the overall pattern showing no PAH biodegradability but large fractions of highly mobile PAHs, concluding that mass transfer limitations may only be one of many factors governing biodegradability of PAHs.
采用连续超临界流体（CO₂）萃取法（SSFE）对8种来自不同来源的历史污染土壤进行处理，旨在阐明高分子量多环芳烃（PAHs）的吸附 - 解吸行为。该方法包括五个萃取阶段，通过提高流体温度和密度，依次施加更严苛的条件，从不同土壤颗粒位点 mobilizing 目标化合物。根据在最温和萃取条件下获得的易解吸（可利用）PAH 组分，确定了两组土壤。例如，荧蒽和芘的易解吸组分在不同土壤之间显著变化，范围从<10%到>90%。此外，萃取行为与分子量密切相关，表明随着分子量增加，可利用的 PAH 组分减少。发现诸如粒度分布和有机干质量等物理化学土壤参数对不同土壤中 PAHs 的吸附 - 解吸行为没有明显影响。然而，PAH 谱与易获得的污染物组分显著相关；PAHs 迁移性相对较低的土壤中五环和六环 PAHs 的比例较高，反之亦然。最终，在两个最温和的萃取阶段，生物降解性与 PAH 回收率良好对应。然而，仅针对具有可生物降解 PAHs 的土壤建立了定量关系。在八种土壤中，五种没有显示出生物降解，包括四种易解吸 PAHs 组分最低的土壤。只有一种土壤（被发现对费氏弧菌具有高毒性）不符合总体模式，显示没有 PAH 生物降解性，但有大量高迁移性的 PAHs，得出传质限制可能只是控制 PAHs 生物降解性的众多因素之一的结论。 （注：原文中“mobilizing”这个词在这里的准确含义不太明确，翻译时保留了英文，以便读者理解原文的不明确之处。）
