Polycyclic aromatic hydrocarbons (PAHs) are health-concerning organic compounds that accumulate in the environment. Bioremediation and phytoremediation are studied to develop eco-friendly remediation techniques. In this study, the effects of two plants (Medicago sativa L. and Trifolium pratense L.) on the PAHs’ bioaccessibility in an aged-contaminated soil throughout a long-term rhizoremediation trial was investigated. A bioaccessibility measurement protocol, using Tenax^® beads, was adapted to the studied soil. The aged-contaminated soil was cultured with each plant type and compared to unplanted soil. The bioaccessible and residual PAH contents were quantified after 3, 6 and 12 months. The PAHs’ desorption kinetics were established for 15 PAHs and described by a site distribution model. A common Tenax^® extraction time (24 h) was established as a comparison basis for PAHs bioaccessibility. The rhizoremediation results show that M. sativa developed better than T. pratense on the contaminated soil. When plants were absent (control) or small (T. pratense), the global PAHs’ residual contents dissipated from the rhizosphere to 8% and 10% of the total initial content, respectively. However, in the presence of M. sativa, dissipation after 12 months was only 50% of the total initial content. Finally, the PAHs’ bioaccessible content increased more significantly in the absence of plants. This one-year trial brought no evidence that the presence of M. sativa or T. pratense on this tested aged-contaminated soil was beneficial in the PAH remediation process, compared to unplanted soil.

中文翻译：

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在两个豆科植物的生长过程中，受污染的土壤中PAHs生物可及性的时间演变。

多环芳烃（PAH）是在环境中累积的与健康有关的有机化合物。对生物修复和植物修复进行了研究，以开发生态友好型修复技术。在这项研究中，两种植物的影响（紫花苜蓿属和红车轴 草在整个长期根际修复试验老化污染土壤的多环芳烃生物有效性L.）进行了调查。甲生物有效性测量协议，使用的Tenax ^®珠，适应了研究的土壤。用每种植物类型培养污染过的土壤，并与未种植的土壤进行比较。在3、6和12个月后对生物可及的和残留的PAH含量进行定量。建立了15种多环芳烃的多环芳烃的解吸动力学，并通过位点分布模型进行了描述。一个常见的Tenax ^®提取时间（24小时）被确立为多环芳烃生物有效性的比较基础。该根际修复结果表明，紫花苜蓿发展好于红三叶对被污染的土壤。当植物不存在（对照）或较小（T. pratense）时），根际总PAHs的残留量消散至总初始含量的8％和10％。然而，在有苜蓿的情况下，12个月后的耗散仅为总初始含量的50％。最后，在没有植物的情况下，PAHs的生物可利用含量显着增加。这项为期一年的试验带来的，没有证据表明存在紫花苜蓿或红三叶这个测试中年污染土壤是在PAH整治过程中是有利的，相比unplanted土壤。