Details

Autor(en) / Beteiligte

• Debenest, T.
• Turcotte, P.
• Gagné, F.
• Gagnon, C.
• Blaise, C.

Titel

Ecotoxicological impacts of effluents generated by oil sands bitumen extraction and oil sands lixiviation on Pseudokirchneriella subcapitata

Ist Teil von

• Aquatic toxicology, 2012-05, Vol.112-113, p.83-91

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2012

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• ► We studied the effects of effluents (process-affected water and lixiviate) generated by oil sands mining activities on a microalgae. ► We assessed the esterase activity and the chlorophyll autofluorescence with a flow cytometer and the early steps of the photosynthesis with a Plant Efficiency Analyzer fluorometer. ► Process-affected water (OSPW) showed the highest toxicity. ► Lixiviate was more toxic than water exposed to oil sand. ► OSPW was highly enriched in trace metals and metalloids such as vanadium and iron. The exploitation of Athabasca oil sands deposits in northern Alberta has known an intense development in recent years. This development has raised concern about the ecotoxicological risk of such industrial activities adjacent to the Athabasca River. Indeed, bitumen extraction generated large amounts of oil sands process-affected water (OSPW) which are discharged in tailing ponds in the Athabasca River watershed. This study sought to evaluate and compare the toxicity of OSPW and oil sands lixiviate water (OSLW) with a baseline (oil sands exposed to water; OSW) on a microalgae, Pseudokirchneriella subcapitata, at different concentrations (1.9, 5.5, 12.25, 25 and 37.5%, v/v). Chemical analyses of water-soluble contaminants showed that OSPW and OSLW were enriched in different elements such as vanadium (enrichment factor, EF=66 and 12, respectively), aluminum (EF=64 and 15, respectively), iron (EF=52.5 and 17.1, respectively) and chromium (39 and 10, respectively). The toxicity of OSPW on cells with optimal intracellular esterase activity and chlorophyll autofluorescence (viable cells) (72h-IC 50%<1.9%) was 20 times higher than the one of OSW (72h-IC 50%>37.5%, v/v). OSLW was 4.4 times less toxic (IC 50%=8.5%, v/v) than OSPW and 4.5 times more toxic than OSW. The inhibition of viable cell growth was significantly and highly correlated (<−0.7) with the increase of arsenic, beryllium, chromium, copper, lead, molybdenum and vanadium concentrations. The specific photosynthetic responses studied with JIP-test (rapid and polyphasic chlorophyll a fluorescence emission) showed a stimulation of the different functional parameters (efficiency of PSII to absorb energy from photons, size of effective PSII antenna and vitality of photosynthetic apparatus for energy conversion) in cultures exposed to OSPW and OSLW. To our knowledge, our study highlights the first evidence of physiological effects of OSPW and OSLW on microalgae.