During the ftrst 17 days of the oil accident, 72 km of shoreline were contaminated.
Estimates are that at the end of April 10,000 t of oil were left on the shore, but the
oiled shores were distributed over 320 km of coastline. 6000 men, mostly military
personnel and up to 1500 volunteers worked with the oil and removed about
100,000 t of material, mostly sand and seaweed, including about 25% oil. By June,
1978, before the tourist season started, most beaches appeared to be clean. However,
in many cases, the view was deceptive, because a considerable amount of oil had been
buried under the sand. There were 1.5 million tourists less than normal, the oyster
beds were ruined. But at the end of May seaweeds could be harvested, and ftsheries
were never seriously impaired. The biological damage to the shore biota was considerable; what long-term damage was caused, the future will tell (Hann et al. 1978).
Only 5 weeks after the "Amoco Cadiz" accident, on April 28, 1978, a near-accident
happened in the English Channel. The Kuwait tanker "AI Fahia" with 267,000 t of
crude oil bound for Wilhelmshaven, happened to sail on the wrong side of the seaway.
The vessel could be warned by British sea police when it was only 2 nautical miles
away from the dangerous Fall Bank. It is said that a failure in the giro compass was
reason for the navigational error (Anon 1978).
Since then many tanker accidents have occurred, and some accidents with oil platforms. The largest spill ever recorded was the blowout of the oil rig "Ixtoc I" in the
Gulf of Mexico, off the state Campeche, Mexico, on June 3, 1979. During the ftrst
period about 4000 t of oil per day went into the sea. Efforts to stop the oil resulted
only in a reduction of the flow, and when ftnally after 9 months, on March 24,
1980, the hole was closed with a 30 t concrete top, approximately 0.5 million t of oil
had polluted the area. The damage was considerable, and also the money spent in
clean-up measures. However, in October 1980 newspapers recorded that the recovery
of the Gulf of Mexico from the oil pest was quicker than expected, and ftsheries and
tourist industry are more or less normal again.
5.4 Effect of Oil on Marine Life
To date, very little is known about the effect of petroleum components that reach the
sea via the atmosphere or via rivers. The possibility cannot be excluded that the fairly
substantial amounts of oil that reach the sea through effiuents are responsible for the
expansion of an impoverished, altered coastal environment and the disappearance of
sensitive types of organisms close to the outfalls. These are also the observations that are
being made in the immediate area around oil refmeries in coastal regions (see Chap. 2.8).
These are, however, local manifestations, and it is difficult to demonstrate that oil alone
is the main reason for such environmental deterioration, because normally other stress
factors act simultaneously .One should be specially careful with generalizations , because
it has not been possible, up to now, to demonstrate adverse effects upon marine life in
the surrounding of natural submarine petroleum seeps, as they occur in the Santa Barbara Channel (see Chap. 5.3), or in areas which are chronically polluted from oil exploration (Lake Maracaibo, Venezuela, coastal areas of Louisiana, U.S .A.). It is possible that
organisms living under chronic petroleum stress adapt to these conditions and are more
tolerant of toxic effects of oil than organisms from unpolluted areas (Mertens 1977).
87
Estimates are that at the end of April 10,000 t of oil were left on the shore, but the
oiled shores were distributed over 320 km of coastline. 6000 men, mostly military
personnel and up to 1500 volunteers worked with the oil and removed about
100,000 t of material, mostly sand and seaweed, including about 25% oil. By June,
1978, before the tourist season started, most beaches appeared to be clean. However,
in many cases, the view was deceptive, because a considerable amount of oil had been
buried under the sand. There were 1.5 million tourists less than normal, the oyster
beds were ruined. But at the end of May seaweeds could be harvested, and ftsheries
were never seriously impaired. The biological damage to the shore biota was considerable; what long-term damage was caused, the future will tell (Hann et al. 1978).
Only 5 weeks after the "Amoco Cadiz" accident, on April 28, 1978, a near-accident
happened in the English Channel. The Kuwait tanker "AI Fahia" with 267,000 t of
crude oil bound for Wilhelmshaven, happened to sail on the wrong side of the seaway.
The vessel could be warned by British sea police when it was only 2 nautical miles
away from the dangerous Fall Bank. It is said that a failure in the giro compass was
reason for the navigational error (Anon 1978).
Since then many tanker accidents have occurred, and some accidents with oil platforms. The largest spill ever recorded was the blowout of the oil rig "Ixtoc I" in the
Gulf of Mexico, off the state Campeche, Mexico, on June 3, 1979. During the ftrst
period about 4000 t of oil per day went into the sea. Efforts to stop the oil resulted
only in a reduction of the flow, and when ftnally after 9 months, on March 24,
1980, the hole was closed with a 30 t concrete top, approximately 0.5 million t of oil
had polluted the area. The damage was considerable, and also the money spent in
clean-up measures. However, in October 1980 newspapers recorded that the recovery
of the Gulf of Mexico from the oil pest was quicker than expected, and ftsheries and
tourist industry are more or less normal again.
5.4 Effect of Oil on Marine Life
To date, very little is known about the effect of petroleum components that reach the
sea via the atmosphere or via rivers. The possibility cannot be excluded that the fairly
substantial amounts of oil that reach the sea through effiuents are responsible for the
expansion of an impoverished, altered coastal environment and the disappearance of
sensitive types of organisms close to the outfalls. These are also the observations that are
being made in the immediate area around oil refmeries in coastal regions (see Chap. 2.8).
These are, however, local manifestations, and it is difficult to demonstrate that oil alone
is the main reason for such environmental deterioration, because normally other stress
factors act simultaneously .One should be specially careful with generalizations , because
it has not been possible, up to now, to demonstrate adverse effects upon marine life in
the surrounding of natural submarine petroleum seeps, as they occur in the Santa Barbara Channel (see Chap. 5.3), or in areas which are chronically polluted from oil exploration (Lake Maracaibo, Venezuela, coastal areas of Louisiana, U.S .A.). It is possible that
organisms living under chronic petroleum stress adapt to these conditions and are more
tolerant of toxic effects of oil than organisms from unpolluted areas (Mertens 1977).
87