Colder and saltier water increases toxic effects of dispersed oil

Temperature and salinity of water can have an effect on how toxic dispersed oil is to organisms in the environment, a council study has found.

The Canadian Centre for Offshore Oil, the Bedford Institute of Oceanography and Department of Fisheries and Oceans conducted a council-sponsored study to look at the absorption of dispersed crude oil during the early life stages of herring, salmon and cod when the fish are most sensitive to toxins.

For example, the study found two main causes of higher toxic effects on herring:

  1. Herring in cold waters develop at a slower rate than their warm water counterparts.
  2. The breakdown of chemicals in cold water is significantly slower than in warm water.

These two factors mean the herring are exposed to toxins for a longer period during their early, more sensitive, life stages.
The study also found that herring were 200 times more sensitive to chemically dispersed crude oil than previously reported.

The council has long endorsed mechanical recovery as the primary tool to combat an oil spill. Unlike dispersant use, which spreads the oil through the water, mechanical recovery with booms and skimmers removes oil from the water.

For more on the council’s research on oil spill dispersants, visit our Dispersants project page.


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