Préface - IMO

Orimulsion ® shorelines studies program
intertidal organisms. Aging significantly increases coating tenacity for dispersed coatings but does not
affect coalesced coating tenacity as much (i.e., immediate washing is very effective in dispersed
coating removal but not coalesced coating removal). Submergence times also affect coating tenacity
with lower intertidal position (lengthy submergence and short drying periods). Dispersed bitumen
coatings were more easily removed from lower intertidal simulations but coalesced bitumen coatings
showed little effect in removal efficiency between high and low tide simulations. Chemical pretreatment
of the coatings with Corexit 9580 dramatically improved removal efficiencies of dispersed
coatings but not coalesced coatings. These results have implications for cleanup strategies of
Orimulsion ® spills.
Bitumen Behaviour and Removal in Coarse Sediments (Harper et al. 2002)
Currently On-Going
This project is designed to address the behaviour and removal of bitumen contamination in
coarse-grained beach sediments where penetration of bitumen to subsurface sediments may be of
concern. In these experiments we are using test sediments of granules, medium pebbles and very large
pebbles (mean diameter 3.4, 14.5 and 43 mm respectively) that are held in containers 28 cm in
diameter and 38 cm deep and that have a natural tidal cycling regime. The study has three stages, (i)
to develop a standardized method to apply dispersed and coalesced bitumen to the coarse grained
sediment test substrates and to estimate the quantity of bitumen retained on and in the substrate, (ii)
determine typical penetration depths, spatial profiles and retention of bitumen within the coarse
grained test substrates, and (iii) conduct preliminary assessment into bitumen cleanup/recovery.
The sediments are being exposed to a dispersed bitumen plume on a falling tide. The dispersed
bitumen readily penetrates the sediments and has the potential to produce thin-layer bitumen coatings
in the subsurface. The thick and viscous coalesced form of bitumen is being applied as a pancake to
the surface of the sediments (Illustration3) on a falling tide and allowed to penetrate the subsurface.
Generally, the bitumen tends to bond together the sediment grains to the depth of penetration (Fig 4).
REFERENCES
Fieldhouse, B. and G. A. Sergy. 2001. Standard Methods to Prepare Bitumen Coated Rock Substrates
for Experimental Studies. Emergencies Science Division, Environment Canada, Edmonton, Alberta.
60pp
Guénette, C.C. and G.A. Sergy. 1999. Disposal Options for Recovered Bitumen. Manuscript Report
EE-168, Emergencies Science Division. Environment Canada, Ottawa, Canada. 98 pp.
Guénette, C.C., G.A. Sergy and B. Fieldhouse. 1998. Removal of Stranded Bitumen from Intertidal
Sediments Using Chemical Agents. Phase I: Screening of Chemical Agents. Manuscript Report EE-
162, Environment Canada, Ottawa, Canada. June 1, 1998, 18 pp.
Harper, J. R. and M.Kory. 1997. Orimulsion ® Shoreline Studies Program: Sediment Interaction
Experiments. Manuscript Report No. EE-159, Environment Canada, Ottawa Canada.
Harper, J. G. Sergy and S. Ward. 2002. Hydraulic Removal of Orimulsion ® Bitumen Coatings from
Rock Surfaces (report in review)
Harper, J. G. Sergy and S. Ward. 2002. Evaluation of Orimulsion ® Bitumen Behaviour in Coarse
Sediments and Potential Remediation Techniques (study in progress).
Owens, E.H. and G. A. Sergy, 1999. Orimulsion ® Spill Field Guide for the Protection and Cleanup of
Marine Shorelines. Emergency Science Division, Environment Canada, Edmonton, Alberta, 194 pp.
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