Weathering Processes Affecting Spills
Weathering is a series of chemical and physical changes that cause spilled oil to break down and become heavier than water. Winds, waves, and currents may result in natural dispersion, breaking a slick into droplets which are then distributed throughout the water. These droplets may also result in the creation of a secondary slick or thin film on the surface of the water.
This is what happens to oil when it is spilled.
The figure shows the weathering processes affecting oil spills:
- Adsorption (sedimentation) is the process by which one substance is attracted to and adheres to the surface of another substance without actually penetrating its internal structure.
- Biodegradation is the degradation of substances resulting from their use as food energy sources by certain micro-organisms including bacteria, fungi, and yeasts.
- Dispersion is the distribution of spilled oil into the upper layers of the water column by natural wave action or application of chemical dispersants.
- Dissolution is the act or process of dissolving one substance in another.
- Emulsification is the process whereby one liquid is dispersed into another liquid in the form of small droplets.
- Evaporation occurs when the lighter substances within the oil mixture become vapors and leave the surface of the water. This process leaves behind the heavier components of the oil, which may undergo further weathering or may sink to the ocean floor.
- Oxidation occurs when oil contacts the water and oxygen combines with the oil to produce water-soluble compounds. This process affects oil slicks mostly around their edges. Photo Oxidation is a sunlight-promoted chemical reaction of oxygen in the air and oil.
Knowledge Check Choose the best answer for the question.
2-6. Which of the following is the process whereby one liquid is dispersed into another liquid in the form of small droplets?
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