Naphthenic acids are naturally-occurring, aliphatic or alicyclic carboxylic acids found in petroleum. Water used to extract bitumen from the Athabasca oil sands becomes toxic to various organisms due to the presence of naphthenic acids released from the bitumen. Natural biodegradation was expected to be the most cost-effective method for reducing the toxicity of the oil sands process water (OSPW). However, naphthenic acids are poorly biodegraded in the holding ponds located on properties leased by the oil sands companies. In the present study, chemical oxidation using ozone was investigated as an option for mitigation of this toxicity. Ozonation of sediment-free OSPW was conducted using proprietary technology manufactured by Seair Diffusion Systems Inc. Ozonation for 50min generated a non-toxic effluent (based on the Microtox bioassay) and decreased the naphthenic acids concentration by approximately 70%. After 130min of ozonation, the residual naphthenic acids concentration was 2mgl(-1): <5% of the initial concentration in the filtered OSPW. Total organic carbon did not change with 130min of ozonation, whereas chemical oxygen demand decreased by approximately 50% and 5-d biochemical oxygen demand increased from an initial value of 2mgl(-1) to a final value of 15mgl(-1). GC-MS analysis showed that ozonation resulted in an overall decrease in the proportion of high molecular weight naphthenic acids (n> or = 22).
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.chemosphere.2007.10.051 | DOI Listing |
Environ Sci Pollut Res Int
January 2025
Department Chemical and Food Engineering, UFSC, Florianópolis, 88040-900, SC, Brazil.
Produced water management is a significant challenge for the oil and gas industry. Due to the large volumes and complex composition of this water, treatment requires special attention, resulting in high costs for companies in the sector. Naphthenic acids, known for their recalcitrance, add a layer of complexity to the treatment process.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
LysisLogic Scientific Inc., Energy Transition Centre, Calgary, Alberta T2P 0H3, Canada.
This Perspective explores the transformative impact of ultrahigh-resolution mass spectrometry (UHR-MS), particularly Fourier transform ion cyclotron resonance (FT-ICR-MS), in the characterization of complex environmental and petroleum samples. UHR-MS has significantly advanced our ability to identify molecular formulas in complex mixtures, revolutionizing the study of biogeochemical processes and organic matter evolution on wide time scales. We start by briefly reviewing the main technological advances of UHR-MS in the context of petroleum and environmental applications, highlighting some of the challenges of the technology such as quantitation and structural identification.
View Article and Find Full Text PDFSci Total Environ
December 2024
Environment and Climate Change Canada, Saskatoon, Saskatchewan S7N 3H5, Canada. Electronic address:
The Athabasca oil sands region of Alberta, Canada contains one of the world's largest unconventional petroleum deposits. There is concern about residual contaminants where tailings are integrated during reclamation and the related adverse effects this may have. Some of the primary toxic organic contaminants in oilsands tailings are naphthenic acid fraction compounds (NAFCs).
View Article and Find Full Text PDFSci Total Environ
December 2024
Department of Chemistry, Chemical Analysis & Mass Spectrometry Facility, University of New Orleans, New Orleans, Louisiana 70148, USA; Pontchartrain Institute for Environmental Sciences, Shea Penland Coastal Education & Research Facility, University of New Orleans, New Orleans, Louisiana 70148, USA; Department of Chemistry, University of Alaska Anchorage, Anchorage, AK 99508, USA. Electronic address:
Crude oil toxicity to early life stage fish is commonly attributed to polycyclic aromatic hydrocarbons (PAHs). However, it remains unclear how the polar unresolved complex mixture (UCM), which constitutes the bulk of the water-soluble fraction of crude oil, contributes to crude oil toxicity. Additionally, the role of photomodification-induced toxicity in relation to the polar UCM is not well understood.
View Article and Find Full Text PDFSci Total Environ
December 2024
Watershed Hydrology and Ecology Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, Saskatoon, Saskatchewan S7N 3H5, Canada.
To assess aquatic toxicity of natural wetlands in the Athabasca oil sands region (AOSR) of northern Alberta, fifteen collected water samples were tested for their ability to affect survival and development of fathead minnow embryos. Wetland waters were also assessed for toxicants from natural oil sands bitumen deposits (Na, Cl, metals, naphthenic acids (NAs), naphthenic acid fraction compounds (NAFCs), polycyclic aromatic hydrocarbons (PAHs), and alkylated PAHs). Water samples from four wetlands caused toxicity to fish embryos.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!