【作者】 高彦征；

【导师】 朱利中；

【作者基本信息】 浙江大学 ， 环境科学， 2004， 博士

【摘要】 植物修复及其强化技术在土壤多环芳烃（PAHs）等有机污染修复中有较大的应用潜力。本文在评述土壤有机污染植物修复研究现状的基础上，围绕表面活性剂强化植物修复土壤PAHs污染的新技术原理，研究植物修复土壤PAHs污染的效率及机制，探讨了植物吸收积累、微生物降解土壤中PAHs的相对贡献率；以水培体系模拟研究了表面活性剂对植物吸收PAHs的强化作用及机理；探讨了表面活性剂强化植物修复土壤PAHs污染的效率及影响因素；用实验数据检验限制分配模型预测植物吸收PAHs等有机污染物的准确性，并系统分析了影响模型参数α_pt值的因素。论文取得一些有价值的成果： （1） 发现Tween80能增强植物吸收积累溶液中的菲和芘。培养液中菲和芘起始浓度为1.0和0.12 mg／L时，低浓度Tween80（＜13.2 mg／L）能显著增强黑麦草和红三叶吸收菲和芘，浓度为6.6 mg／L时，促进作用最强，根和茎叶中菲和芘含量、积累量、富集系数为无Tween80对照处理的～216％；高浓度Tween80（＞39.6mg／L）则会抑制根和茎叶吸收积累菲和芘。 （2） 率先研究了表面活性剂增效植物修复土壤PAHs污染的新技术原理。施加少量的Tween80（≤1000 mg／kg）或Brij35（≤600 mg／kg）能显著提高黑麦草和苜蓿草修复土壤芘污染的效率，如施加600 mg／kg Tween80或300 mg／kg Brij35，50天后种植黑麦草土壤中芘的去除率分别为96.47％和97.84％，残留浓度为3.71和2.28 mg／kg，分别比无表面活性剂对照处理降低了54.31％和71.92％；供试浓度0～3000 mg／kg内，施加SDS明显抑制土壤中芘的降解；浓度≤600 mg／kg时，CTMAB也能强化植物修复土壤芘的效率，但由于对植物生长有明显毒害效应，CTMAB不适于用做植物修复土壤污染的增效试剂。表面活性剂强化植物修复土壤芘的主要机制是表面活性剂增强土壤中芘的（土著）微生物降解作用，而植物吸收积累的芘占土壤中芘总降解量的比例均不足0.1％。 （3） 限制分配模型能较好地预测植物中PAHs（菲）含量，有望用于评价污染土壤区植物PAHs污染、监测农产品安全。以黑麦草、菜心和苋菜为例，尽管45天后土壤中菲浓度变化很大（从不足1 mg／kg到约45 mg／kg），模型的预测值和实测值差别均在一个数量级以内，根和茎叶中菲含量的预测误差分别低于81％和103％。时间、植物组成、有机污染物性质、生长介质和表面活性剂等会影响限制分配模型关键参数α_pt值的大小。 （4）发现生长于污染土壤的植物根中菲和花含量和根系富集系数与根脂肪含量显著正相关（p<0.05，n二12）;根和茎叶中菲和花含量与土壤污染强度正相关，富集系数则与其呈负相关;同种植物根中花含量、富集系数明显大于菲，而植物对花的传输系数则远小于菲。分析得出植物对土壤菲和花污染的修复作用主要是植物提高了微生物降解活性，而植物吸收积累的贡献小于0.23%。更多还原

【Abstract】 Soil contamination with polycyclic aromatic hydrocarbons (PAHs) poses a great threat worldwide to the agricultural food quality and human health, and calls for an immediate action to remediate the contaminated sites. The prospect of phytoreme-diation for soil organic contaminants is an attractive cost-effective alternative to traditional engineering approaches. However, the basic mechanisms involved are up-to-date not well elucidated. For PAHs are liable to be sorbed by soil solids, the plant and microbial availability of PAHs in soils is a major limiting factor of phytore-mediation efficiencies. The use of surfactants to enhance the apparent aqueous solubility, desorption of organic compounds from solids and microbial bioavailability of PAHs in soil solution has been well documented. However, to the best of our knowledge, there is a lack of experimental data to elucidate the rate and extent of plant uptake of hydrophobic organic compounds such as PAHs in the presence of surfactants. Little information is available on the surfactant-enhanced phytoremediation for organic contaminated soils.In this dissertation, the mechanisms of the phytoremediation for soil PAHs were evaluated based on the studies of plant uptake and accumulation of these compounds. The effects of surfactants on plant uptake and accumulation of phenanthrene and pyrene in surfactant-laden solution were investigated. The basic behaviors and mechanisms of surfactant-enhanced phytoremediation were studied. Based on the experimental results and data from literatures, the performance of a partition-limited model on the prediction of plant PAH contamination was evaluated. The main original conclusions are shown as follows.(1) Root concentrations and concentration factors (RCFs) of phenanthrene and pyrene in soils displayed significantly positive correlations with root lipid contents (p<0.05, n=12). Root and shoot concentrations of tested PAHs were positively correlated to their soil concentrations, whereas RCFs and SCFs (shoot concentration factors) showed negatively a correlation with their soil concentrations. Moreover, root concentrations and RCFs of pyrene were generally much higher, and TFs values of pyrene were significantly smaller than those of phenanthrene. The presence of vegetation evidently enhanced the remediation of phenanthrene and pyrene in soil environment. However, plant uptake and accumulation only accounted for less than 0.23% of the enhanced loss of these chemicals in vegetated versus non-vegetated soils. In contrast, plant-promoted microbial biodegradation was the dominant mechanism of the phytoremediation for soil phenanthrene and pyrene contaminants.(2) The presence of a nonionic surfactant (Tween80) can significantly enhanced plant uptake of two representative PAHs, phenanthrene and pyrene, from an aqueous solution with the initial phenanthrene of 1.0 mg/L and pyrene of 0.12 mg/L. Tween80 under a wide range of concentrations (0-105.6 mg/L) did not show any apparent phytotoxity toward the growth of ryegrass (Lolium multiflorum Lam) and red clover {Trifolium pretense L.). The presence of Tween80 with lower concentrations generally enhanced the plant uptake based on the plant concentrations, accumulated amounts and PCFs (plant concentration factors) of these two PAHs. The maximal plant uptake was observed at 6.6 mg/L Tween80, in which PAH concentrations, accumulation amounts and PCFs were ~216% of those in Tween80-free controls.(3) The basic behaviors and mechanisms of the surfactant-enhanced phytoremediation (SEPR) for soil pyrene were originally investigated. The amendment of Tween80 (<1000 mg/kg) or Brij35 (<600 mg/kg) significantly enhanced the phytoremediation efficiencies, whereas the addition of SDS would evidently inhibit the degradation of pyrene in soils. As the added concentration lower than 600 mg/kg, CTMAB would clearly promote pyrene dissipation. However, for CTMAB showed apparent phytotoxity toward the growth of tested plants, CTMAB was the last candidate to be utilized as the amendment. The dominant me更多还原