Biodegradation of petroleum hydrocarbons in a weathered, unsaturated soil is inhibited by peroxide oxidants

Onur G. Apul, Sarah Arrowsmith, Caitlyn A. Hall, Evelyn M. Miranda, Fabiha Alam, Paul Dahlen, Kanwartej Sra, Roopa Kamath, Sara J. McMillen, Natasha Sihota, Paul Westerhoff, Rosa Krajmalnik-Brown, Anca G. Delgado

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Field-weathered crude oil-containing soils have a residual concentration of hydrocarbons with complex chemical structure, low solubility, and high viscosity, often poorly amenable to microbial degradation. Hydrogen peroxide (H2O2)-based oxidation can generate oxygenated compounds that are smaller and/or more soluble and thus increase petroleum hydrocarbon biodegradability. In this study, we assessed the efficacy of H2O2-based oxidation under unsaturated soil conditions to promote biodegradation in a field-contaminated and weathered soil containing high concentrations of total petroleum hydrocarbons (25200 mg TPH kg−1) and total organic carbon (80900 mg TOC kg−1). Microcosms amended with three doses of 48 g H2O2 kg−1 soil (unactivated or Fe2+-activated) or 24 g sodium percarbonate kg−1 soil and nutrients did not show substantial TPH changes during the experiment. However, 7.6–41.8% of the TOC concentration was removed. Furthermore, production of DOC was enhanced and highest in the microcosms with oxidants, with approximately 20–40-fold DOC increase by the end of incubation. In the absence of oxidants, biostimulation led to > 50% TPH removal in 42 days. Oxidants limited TPH biodegradation by diminishing the viable concentration of microorganisms, altering the composition of the soil microbial communities, and/or creating inhibitory conditions in soil. Study's findings underscore the importance of soil characteristics and petroleum hydrocarbon properties and inform on potential limitations of combined H2O2 oxidation and biodegradation in weathered soils.

Original languageEnglish (US)
Article number128770
JournalJournal of Hazardous Materials
StatePublished - Jul 5 2022


  • Chemical oxidation
  • Crude oil
  • Hydrocarbon biodegradation
  • Hydrogen peroxide
  • Landfarming
  • Sodium percarbonate

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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