Oil spills

To develop suitable prevention and response strategies, it is essential to identify the sources of oil discharge into the marine environment, as well as their contribution to the phenomenon of “black tides”. This is no easy task. Although accidents involving oil spills may be well documented, the same cannot be said for the rest. For example, incidences of operational discharge can only be assessed approximately.

Accidental discharge

In the same way, the reliability of data on industrial and urban discharge is highly variable from one country to another. The extent of discharge from natural sources can only be estimated in a very general fashion. It is therefore not surprising to see considerable variation in the quantities quoted from one document to another.

The diagram below presents the data used as a reference in the work of the International Maritime Organization.

Only direct discharges into the water have been included here, excluding the share of atmospheric emissions that rain and streams transfer into the water. The method used to estimate such sources varies from one documentary source to another, generating estimations that are not always consistent.


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Sources of hydrocarbons in the marine environment in 2000

Source: data from CLARK. Marine pollution

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Oil spill: definitions

The accidental release of oil, or other petroleum products usually into freshwater or marine ecosystems, and usually in large quantities. It can be controlled by chemical dispersion, combustion, mechanical containment, and absorption. (Source: EEA multilingual environmental glossary, http://glossary.eea.europa.eu/EEAGlossary, October 2006)

A form of pollution in which oil from various sources leaks into the water. (Source: US Environmental Protection Agency)
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Black tide: definitions

A major oil slick which threatens to reach and pollute the shore (Source: ZILBERBERG. Elsevier’s Dictionary of Marine Pollution)
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Large-scale oil pollution at sea (Source: American Dialect Society)