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Abstract

Dichlorodiphenyltrichloroethane (DDT) was used across the world for over 50 years but was banned due to its ecotoxic effects. It is classed as a persistent organic pollutant (POP) because its highly hydrophobic nature allows it to bioaccumulate and biomagnify up the food chain. The transformation products of DDT that appear due to natural processes are also harmful environmental pollutants. Many strategies have been used to manage DDT contaminated soils, sediments, and waters, but no in-situ environmentally safe remediation strategy exists.

This thesis tests the capacity of multiple white-rot fungi to degrade DDT and its transformation products (DDX) in aged, contaminated soils from former forest nursery sites in Sweden. White-rot fungi can degrade a variety of POPs by producing high redox potential oxidative extracellular enzymes, such as peroxidases and laccases. Their bioremediation capacity was tested on soils of varying DDX concentrations, across various scales, using fungus-inoculated grain, straw, and spent mushroom substrate. Surfactant was applied due to the limited bioavailability of hydrophobic compounds that partition to organic matter. To improve risk assessment and comparison of soil treatment alternatives, partitioning coefficients for DDX were determined for a passive sampling material (polyoxymethlylene; POM). The method was applied and validated for measurements of freely dissolved DDX concentrations in pore water of contaminated soil.

Overall, this thesis demonstrates the effectiveness of white-rot fungi in degrading DDT and its transformation products. It also explores limitations of upscaling, and how surfactants can mitigate the effects of soil hydrophobic pollutant aging, namely partitioning into organic matter.

Keywords

White-rot fungi; bioremediation; contaminated soil; dichlorodiphenyltrichloroethane; DDT; polyoxymethylene; POM; passive sampling; partitioning coefficients; pilot reactor; spent mushroom substrate

Published in

Publisher: Swedish University of Agricultural Sciences

SLU Authors

UKÄ Subject classification

Bioremediation
Analytical Chemistry
Microbiology

Publication identifier

  • DOI: https://doi.org/10.54612/a.5fcpnu7co3
  • ISBN: 978-91-8124-248-5
  • eISBN: 978-91-8124-278-2

Permanent link to this page (URI)

https://res.slu.se/id/publ/146507