Issue 11: Spills |
| Description |
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Spills generally refer to episodic accidental releases of oil into the aquatic environment. In 1996, approximately 4,200 oil spills occurred in coastal areas and in the open ocean. Spill sources range from minor marina activities to one-time releases from tankers, with major tanker spills accounting for only 5 percent of the volume of oil spills. Fixed facilities and offshore exploration and production platforms contribute 15 million gallons of oil pollution to the world’s ocean bodies annually. By contrast, 363 million gallons of oil per year reaches the ocean in runoff from land and municipal and industrial wastes. In fact, the yearly road runoff from a city of 5 million could contain as much oil as one large tanker spill (Ocean Planet, 1995). Natural oil seeps discharge 62 million gallons of oil into marine waters annually. Effects on organisms from oil spills can be acute, such as fish kills from initial contact with the toxic fractions of petroleum, or subtle, such as chronic effects on reproduction which become evident as toxic chemicals concentrate through the food web of an ecosystem. Effects on human populations are realised through economic losses, such as those associated with the loss of a fishery or tourism. Particularly susceptible to injury from releases of oil are exposed shorelines, shallow reef environments, estuaries, mangrove forests, and wetlands. |
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GIWA definition |
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Spills refers to the adverse effects of accidental episodic releases of contaminants and materials to the aquatic environment as a result of human activities. |
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Environmental impacts |
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1. Increased avian mortality 2. Increased mortality of aquatic life 3. Habitat damage 4. Long term contamination of sediments and beaches with associated ecological changes |
Indicators | |
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The following are environmental impact indicators for spills. Select the environmental impact indicators that are relevant from the list below and input data into the appropriate indicator sheets. | |
| POL |
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| PAR |
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| EFF |
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| SAT |
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| BIO |
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| PROX |
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