Date of Award


Publication Type

Master Thesis

Degree Name



Great Lakes Institute for Environmental Research


Christopher Weisener


flux, gamma irradiation, geochemistry, naphthenic acid, oil sands




Naphthenic acids (NA) are components of most petroleum, including those found in the Athabasca oil sands and in some systems are considered to be persistent compounds. Their presence in the environment can pose significant problems since freshly released NAs are toxic to aquatic organisms. In this investigation gamma irradiation (GI) was used to reduce the toxicity and concentration of NAs in oil sand tailings and assess the impact on biogeochemical processes. GI reduced NA concentration by up to 97% in Oil Sands Process Water (OSPW) and 85% in fluid fine tailings (FFT). Dissolved oxygen flux was stimulated directly in the GI-treated FFT in both fresh and aged sources, while increases in hydrogen sulfide flux was restricted to the fresh FFT source material. Acute toxicity to Vibrio fischeri was immediately reduced following GI treatment of fresh OSPW. GI treatment followed by 28-day incubation reduced toxicity of aged OSPW to Vibrio fischeri.