Simulating diluted bitumen spills in boreal lake limnocorrals - part 2: Factors affecting the physical characteristics and submergence of diluted bitumen

We examined the fate and behaviour of diluted bitumen (dilbit) as it weathered for 70 days in freshwater limnocorrals (10 m diameter × 1.5 m depth) installed in a boreal lake to simulate dilbit spills in a natural aquatic environment. We added seven different dilbit spill volumes, ranging from 1.5 t...

Full description

Saved in:
Bibliographic Details
Published in:The Science of the total environment 2021-10, Vol.790, p.148580-148580, Article 148580
Main Authors: Stoyanovich, S., Rodríguez-Gil, J.R., Hanson, M.L., Hollebone, B.P., Orihel, D.M., Palace, V.P., Faragher, R., Mirnaghi, F.S., Shah, K., Yang, Z., Blais, J.M.
Format: Article
Language:English
Subjects:
Dilbit
Freshwater
Limnocorral
Natural weathering
Submerged oil
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We examined the fate and behaviour of diluted bitumen (dilbit) as it weathered for 70 days in freshwater limnocorrals (10 m diameter × 1.5 m depth) installed in a boreal lake to simulate dilbit spills in a natural aquatic environment. We added seven different dilbit spill volumes, ranging from 1.5 to 180 L, resulting in oil-to-water ratios between 1:71,000 (v/v, %) and 1:500 (v/v, %). Volatile hydrocarbons in the dilbit slick decreased rapidly after the dilbit was spilled on the water's surface, and dilbit density and viscosity significantly increased (>1 g mL−1 and >5,000,000 mPa s, respectively). Dilbit sank to the bottom sediments in all treatments, and the time to sinking was positively correlated with spill volume. The lowest dilbit treatment began to sink on day 12, whereas the highest dilbit treatment sank on day 31. Dilbit submerged when its density surpassed the density of freshwater (>0.999 g mL−1), with wind, rain, and other factors contributing to dilbit sinking by promoting the break-up of the surface slick. This experiment improves our ability to predict dilbit's aquatic fate and behaviour, and its tendency to sink in a boreal lake. Our findings should be considered in future pipeline risk assessments to ensure the protection of these important aquatic systems. [Display omitted] •Dilbit density and viscosity quickly surpasses thresholds of efficient recovery.•Dilbit sinks between 12 and 31 days following the spills.•The onset of dilbit submergence is related to the volume of dilbit spilled.•Suspended sediments and mixing not likely drivers of submergence in this study.
ISSN:0048-9697
1879-1026
DOI:10.1016/j.scitotenv.2021.148580