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The phytoremediation of PFAS contaminated soil using Cannabis sativa L. (hemp) plants

thesis
posted on 2025-05-11, 21:50 authored by Timothy James Wright
Poly and Per-fluoroalkyl substances (PFAS) are a class of persistent organic pollutants (POPs) that pose a significant threat to the health of communities and ecological systems. They are released into soil and water systems as a consequence of their use in Aqueous Fire Fighting Foams (AFF), as waste from plastics or semiconductor manufacturing and as leachate from PFAS-contaminated landfill. PFAS do not fully decay naturally. Current soil remediation techniques are ill-equipped to remediate the large volumes of soil currently impacted by PFAS. Plants have long been used to remediate heavy metals and other POPs, however the ability for plants to remediate PFAS contaminated soil is poorly understood. While a large catalogue of plants have been investigated for their ability to remediate PFAS, Cannabis sativa is underrepresented in the literature. The effect of growth duration and the concomitant changes to plant physiology on PFAS uptake into plants and removal from soil is also poorly understood. Any potential temporal effects on PFAS uptake will be investigated in both individual plant components and in the contaminated soil. The soil will be investigated at each time point using multi-point sampling to develop a complete PFAS concentration profile. It was found that the uptake of PFAS into plants occurred over two distinct phases, rapid uptake during vegetative growth and a slowed uptake during flowering. Potentially as a result of this, young male plants accumulated more than young female plants and vice versa for mature plants. Soil was found to contain less PFAS the longer plants were allowed to grow and despite the distance from the main root mass, PFAS concentration was lowest at the edge of the pots. PFAS removal being independent of root access, highlighted phytoremediation’s potential in large area applications. These results have demonstrated the importance of plant mass, rapid vegetative growth and gender ratio in C.sativa phytoremediation. It has also further improved our understanding of how PFAS migrates through soil during phytoremediation.

History

Year awarded

2024.0

Thesis category

  • Doctoral Degree

Degree

Doctor of Philosophy (PhD)

Supervisors

Bishop, Daniel (University of Newcastle); Kouretzis, Georgios (University of Newcastle); Turner, Brett (University of Technology Sydney); Crompton, Marcus (University of Newcastle)

Language

  • en, English

College/Research Centre

College of Engineering, Science and Environment

School

School of Engineering

Rights statement

Copyright 2024 Timothy James Wright

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