Project 5: Phytoremediation to Degrade Airborne PCB Congeners from Soil and

项目 5：通过植物修复来降解土壤和土壤中空气中的多氯联苯同系物

• 批准号: 7106934
• 负责人: Jerald Lee Schnoor
• 金额: $ 18.35万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7106934
• 关键词: air pollution control; bacteria; bioreactors; biotransformation; chlorination; detoxification; environmental exposure; environmental toxicology; field study; gene expression; ground water; halobiphenyl /halotriphenyl compound; histology; oxidation; plants; soil pollution; waste treatment; water pollution control

This proposal investigates the working hypothesis that phytoremediation can be used to degrade airborne PCB congeners from soil and groundwater sources. Plants stimulate the microbial community in the root zone and contribute to microbial degradation of RGBs (rhizodegradation). Higher-chlorinated PCBs are dechlorinated under reducing (anaerobic) conditions; resulting lesser-chlorinated congeners can undergo oxidative mineralization under aerobic conditions. Alternating reducing and oxidizing conditions in the rhizosphere makes the plant-soil system a natural two-stage bioreactor for initial PCB transformation. Lesser-chlorinated PCBs can also be taken-up and transformed inside plan tissues. The specific aims of the project are (1) to test the hypothesis that poplar plants can take up and detoxify lesser-chlorinated PCB congeners by identifying metabolic pathways of PCBs and genes that encode for catabolic enzymes, (2) to test the hypothesis that bacteria in the rhizosphere can reductively dechlorinate higher-chlorinated PCBs and can mineralize resulting lesser-chlorinated congeners under oxidizing conditions; this will be tested using anaerobic and aerobic batch bioreactors with rhizosphere soils contaminated with PCBs, (3) to test the hypothesis that phytoremediation will allow for significant reductions in the airborne transfer of PCBs from waste disposal sites and mitigate exposure to humans and ecosystems; this innovative cleaning up strategy (based on hypotheses 1 and 2) will be tested at the bench scale and by pot-studies in the greenhouse, (4) to test the hypothesis that residues of PCBs in plant tissues are non-toxic or of greatly reduced toxicity to biota by conducting an eco-toxicological evaluation of the phytoremediation process using a battery of toxicity tests, and (5) to test the hypothesis that higher plants play a significant role in the environmental cycling of airborne PCBs by field analyses of PCB accumulation on vegetation. The significance of this project is that it provides an intervention and remedy for contaminated waste sites that will help to break the continuous cycling of PCBs in the atmosphere and the subsequent exposure to humans.

该提案调查了植物修复可用于降解的工作假设 来自土壤和地下水源的空气中 PCB 同系物。植物刺激微生物群落 位于根区并导致 RGB 的微生物降解（根际降解）。高氯化 PCB在还原（厌氧）条件下脱氯；产生较少氯化的同系物 在有氧条件下可发生氧化矿化。还原和氧化交替 根际条件使植物-土壤系统成为初始 PCB 的天然两级生物反应器 转变。氯化程度较低的多氯联苯也可以在植物组织内被吸收和转化。这 该项目的具体目标是（1）测试杨树植物可以吸收和解毒的假设 通过识别 PCB 的代谢途径和编码基因来减少氯化 PCB 同系物 对于分解代谢酶，（2）检验根际细菌可以还原的假设 对高氯化多氯联苯进行脱氯，并可在条件下矿化所得低氯化同系物 氧化条件；这将使用带有根际的厌氧和需氧间歇式生物反应器进行测试 受 PCB 污染的土壤，(3) 检验植物修复将带来显着效果的假设 减少废物处理场中多氯联苯的空气转移并减少人类接触 和生态系统；这种创新的清理策略（基于假设 1 和 2）将在 通过实验室规模和温室盆栽研究，(4) 检验多氯联苯残留量的假设 通过进行生态毒理学研究，植物组织中的物质是无毒的或对生物群的毒性大大降低 使用一系列毒性测试评估植物修复过程，以及 (5) 测试 假设高等植物在空气中多氯联苯的环境循环中发挥着重要作用 植被上 PCB 积累的现场分析。这个项目的意义在于它提供了一个 对受污染废物场的干预和补救将有助于打破废物的连续循环 大气中的多氯联苯及其随后与人类的接触。