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.
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.
Sources of hydrocarbons in the marine environment in 2000
Source: data from CLARK. Marine pollution
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)