Journal
CHEMOSPHERE
Volume 296, Issue -, Pages -Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2022.133807
Keywords
CEWAF; Dilbit; Dispersant; CROSERF; Droplet size distribution; Petroleum hydrocarbons
Categories
Funding
- National Contaminants Advisory Group (NCAG) within Department of Fisheries and Oceans Canada (DFO)
Ask authors/readers for more resources
This study investigated the effects of various factors on droplet size distribution and accommodated oil concentration in WAF and CEWAF experiments. The results showed that the DSD of WAFs and CEWAFs differed at different oil loading concentrations, with high concentration CEWAFs requiring longer mixing and resting time.
The preparation of Water-accommodated Fractions (WAFs) and chemically enhanced WAFs (CEWAFs) are essential for evaluating oil toxicity. The Chemical Response to Oil Spills: Ecological Research Forum (CROSERF) method was widely adopted, with variables (e.g., mixing time, oil loading, etc.) being continuously changed among research groups, which limits the cooperation in this area. Herein, we conducted WAF and CEWAF experiments using two loadings of diluted bitumen (Dilbit): 1 g/L and 10 g/L. For the CEWAF, the dispersant to oil ratio was 1:20. We investigated the impact of three mixing durations (18 h, 42 h, and 66 h) and two resting times (6 h and 24 h) on the droplet size distribution (DSD) and accommodated oil concentration. This would be highly beneficial for analyzing toxicity from oil spills, especially when considering the toxic effect of both suspended oil droplets and dissolved hydrocarbons. The DSD results and oil chemistry analysis showed that at a low oil loading concentration (1 g/L), both WAFs and CEWAFs had the same DSD, with an average d50 (volume median diameter) of 3.38 +/- 0.70 mu m and 3.85 +/- 0.63 mu m, respectively. At a high oil loading concentration (10 g/L), the WAFs had an average d50 of 3.69 +/- 0.52 mu m, showing no correlation with mixing and resting time. The DSD of CEWAFs increased significantly at 42 h mixing and 24 h resting time, with oil concentration reaching equilibrium after 42 h mixing. Therefore, WAFs appears to require only 18 h mixing and 6 h resting, while it is recommended to have 42 h mixing and 24 h resting for CEWAFs at high dilbit oil loading concentrations.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available