Fate of per- and poly-fluoroalkyl Substances (PFASs) in soils affected by plant and rhizosphere microbial community

全氟烷基和多氟烷基物质(PFAS)是一类在工业上广泛使用的3000多种合成化合物。在人类、饮用水、土壤、植物和野生动物中检测到越来越多的全氟辛烷磺酸。这些发现引起了人们的极大关注，因为全氟辛烷磺酸是持久性的，因此会在环境中积累。全氟辛烷磺酸被认为与癌症发病率增加、干扰胆固醇代谢和扰乱人类内分泌功能有关。全氟辛烷磺酸的一个主要环境来源是在灭火活动和训练演习期间释放的水成膜泡沫(AFF)。一旦AFF被释放到土壤中，全氟辛烷磺酸就可以被土壤中的微生物吸收并潜在地转化。虽然这可能会导致全氟辛烷磺酸从土壤中去除，但关于全氟辛烷磺酸在根际环境(即植物根部周围的土壤)中的去向尚不清楚。其中主要的问题是，是植物、土壤微生物还是两者都对生物降解负有责任。本项目的重点是回答这些问题，并确定哪些因素控制着转型过程。更好地了解控制全氟辛烷磺酸在土壤中去向的机制，将有助于开发具有成本效益的全氟辛烷磺酸污染土壤修复技术。这项工作的结果将成为一项教育推广计划的基础，该计划侧重于代表性不足的群体，以增加全国STEM工作人员的多样性。这项研究的目标是确定影响土壤中全氟烷基物质和多氟烷基物质(PFAS)去向的关键因素，以制定有效的战略来降低PFAS土壤污染的风险。这项研究的重点是描述土壤微生物、植物及其根分泌物的作用，以及植物与土壤微生物之间的协同作用对土壤中全氟辛烷磺酸的去向的影响。具体的研究目标是：i)确定土壤微生物区系在受AFFF影响的土壤中PFAS生物转化中的作用；ii)调查根分泌物对土壤中PFAS归宿的相互影响；以及iii)研究植物/细菌协同作用在土壤PFAS生物转化中的潜在影响。拟议的研究结果将促进对根际和非根际相关微生物介导全氟辛烷磺酸生物转化的潜在机制的基础知识。这项研究将为减轻土壤中全氟辛烷磺酸污染的有效植物修复策略提供洞察力。综合植物及其相关微生物群落的知识的有效处理战略将是一项科学突破，从而减少全氟辛烷磺酸及其潜在的环境前体。拟议的研究为研究生和本科生在微生物学、植物科学和环境工程领域的跨学科培训提供了肥沃的土壤。更广泛的影响将来自于对代表不足的群体的参与和拓展，向科学界传播研究成果，以及在地方、国家和/或国际会议上发表演讲。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Per- and polyfluoroalkyl substances (PFAS) represent a class of over 3,000 synthetic compounds that have been widely used in industry. PFASs are increasingly detected in humans, drinking water, soils, plants, and wildlife. These findings have raised significant concern because PFASs are persistent thus accumulate in the environment. PFAS have been implicated in increased cancer rates, interference with cholesterol metabolism, and disruption of endocrine function in humans. A major environmental source of PFASs are aqueous film-forming foams (AFFFs) released during fire-fighting events and training exercises. Once AFFFs are released to soils, PFAS can be taken up and potentially transformed by microorganisms in the soil. While this can lead to removal of PFAS from soil, much is not known about the fate of PFAS in the rhizosphere environment (i.e., the soil around plant roots). Primary among these is the question whether plants, soil microbes, or both are responsible for the biodegradation. The focus of this project is to answer these questions and identify which factors control the transformation processes. Better understanding of the mechanisms controlling the fate of PFAS in soils will enable the development of cost-effective remediation technologies for PFAS-contaminated soils. Results from this work will form the basis of an educational outreach program focused on under-represented groups to increase the diversity of the Nation's STEM workforce.The goal of this study is to identify key factors affecting the fate of per- and polyfluoroalkyl substances (PFAS) in soils for the development of effective strategies to mitigate risks of PFAS soil contamination. The focus of the proposed study is to delineate the roles of soil microbes, plants and their root exudates, and the synergic interactions between plants and soil microbes on the fate of PFAS in soils. The specific research objectives are to: i) determine the role of soil microbiota in PFAS biotransformation in AFFF-impacted soils; ii) investigate the reciprocal impacts of root exudates on the fate of PFAS in soils; and iii) examine the potential effects of plant/bacterial synergisms in PFAS biotransformation in soils. The results of the proposed study will advance fundamental knowledge on the underlying mechanism mediating PFAS biotransformation by both rhizosphere and non-rhizosphere associated microbes. This research will provide insight into effective phytoremediation strategies for mitigating PFAS contamination in soils. An effective treatment strategy that integrates knowledge of both plants and their associated microbial communities would be a scientific breakthrough, leading to the reduction of PFAS and their potential precursors from the environment. The proposed research serves as a fertile ground for interdisciplinary training of graduate and undergraduate students at the interface of microbiology, plant science, and environmental engineering. Broader impacts will result from the engagement and outreach to under-represented groups, dissemination of research results to the scientific community, and from presentations at local, national and/or international conferences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.