Department of Ecology, February 6, 2020

We know that heavy oil such as asphalt is likely to sink, but what about oils left in the environment – will they eventually submerge or sink, and when? Knowing the possibilities, where, when and why oil may sink help us plan better response actions. This blog establishes a place to have a dialogue with communities, responders, and technical experts to understand the challenges of spill response, learn more about the Washington environment and share information on how oil acts when spilled.

What do we know?

We know that when an oil is “non-floating” we mean one of three things. 1) Oils may submerge or sink because their densities are heavier than water, and oils may become denser the longer they stay in the water. 2) Oils may submerge in the water column when they encounter turbulence, such as currents and waves. Submerged oil may move within the water column. 3) Oils may sink when they encounter sediment as they are washing towards the shore.  Oil may strand on the beach and later refloat and move on. Any one of these conditions poses challenges for us when responding to spills.

What we need to know?

We know that in Washington we are transporting oil that may not remain floating. What we need to know more about is what are the names and physical properties of those oils?  Where are they being transported? In addition, we need to know the characteristics of the water bodies they are moved near and what characteristics could lead oil submerging or sinking, such as the turbulence or sedimentation. Our current oil spill planning tools need to be updated based on this information.