Dispersion of oil in the water column therefore seems to be a practicable method to
eliminate the oil from the sea surface. Some experiments (Fig. 42) indicate that the
dispersal of oil by chemicals enhances the microbial breakdown of oil in seawater.
Britsh oil spill experts summarize their experience as follows:
Norton and Franklin (1980, p. 19):
"Current arrangements for licensing ensure that the dispersants available for use in dispersing oil
at sea or on beaches have as Iowa toxicity as technically possible. Nevertheless, due to the high
toxicity of some oils, dispersions resulting from the use of chemical dispersants may be toxic to
marine life. At sea, where conditions favour the rapid dispersal of a chemically-dispersed slick,
the probability of causing significantly deleterious effects on marine organisms is low and probably restricted to the more sensitive stages such as fish eggs or larvae. Only in shallower waters
and where the oil is relatively fresh is mortality likely to occur in adult fish and shellfish, and to
other forms of marine life. Spraying of intertidal organisms is likely to lead to some increased
mortality of exposed organisms under most conditions."
Department of the Environment (1976, p. 10):
"Qean-up on shore is likely to be less complete, more difficult, more expensive, more ecologically
damaging and slower than treatment at sea. There is thus a clear case in favour of the latter.
Mechanical recovery from the sea has many features of the ideal system, but unfortunately it is
only feasible at the present time in calm conditions, needs ancillary equipment and trained
operators and involves high capital costs. For the time being dispersants provide the only really
effective and generally applicable method of dealing with oil at sea. They are most effective and
can be used in smaller quantities when applied to fresh oil, before "weathering" takes place.
Concentrate dispersants increase the effective spraying time of boats and are considerably more
economical than ordinary dispersant."
However, to utilize chemicals as dispersants against oil on the sea surface is to fight
the devil with Beelzebub, as the German saying goes. Up to now authorities in the
Federal Republic of Germany are reluctant to organize large-scale oil spill fighting
equipment based on chemical dispersants, and they are encouraged by public opinion
which at this moment, 1981, is very much against any introduction of chemicals into
the sea; certainly dispersants have to be ranged under pollutants. Experimental evidence regarding the tOxicity of oil and oil-dispersant mixtures to marine life are not
conclusive, and contrary to the British results from short-term toxicity experiments
(Table 19) there are contradicting results from long-term studies (Fig. 53). It seems
necessary to spend more scientific effort on the question, unbiased by industrial
pressure or emotions, to have better arguments regarding the conflict of damage by
dispersants in the open sea versus damage of oil on the shores.
Other chemicals used to fight oil spills are "herders" which counteract the spreading
of the oil at the sea surface and have the effect that oil creeps together to form larger,
water-repellent units, and "sorbents" which bind the oil by capillarity and adsorption. Polyurethane foam may take up oil 30 times its own weight, and can be reused
after pressing the recovered oil out. Straw is a sorbent that takes up oil about five
times its own weight. At the "Torrey Canyon" oil spill, in 1967 the French Government used pulverized blackboard chalk, to sink the already aged oil that approached
the coasts of Brittany. By the use of 3000 t of chalk, approximately 30,000 t of oil
were eliminated from the sea surface. However, is has been reported that in 1969 oil
99
eliminate the oil from the sea surface. Some experiments (Fig. 42) indicate that the
dispersal of oil by chemicals enhances the microbial breakdown of oil in seawater.
Britsh oil spill experts summarize their experience as follows:
Norton and Franklin (1980, p. 19):
"Current arrangements for licensing ensure that the dispersants available for use in dispersing oil
at sea or on beaches have as Iowa toxicity as technically possible. Nevertheless, due to the high
toxicity of some oils, dispersions resulting from the use of chemical dispersants may be toxic to
marine life. At sea, where conditions favour the rapid dispersal of a chemically-dispersed slick,
the probability of causing significantly deleterious effects on marine organisms is low and probably restricted to the more sensitive stages such as fish eggs or larvae. Only in shallower waters
and where the oil is relatively fresh is mortality likely to occur in adult fish and shellfish, and to
other forms of marine life. Spraying of intertidal organisms is likely to lead to some increased
mortality of exposed organisms under most conditions."
Department of the Environment (1976, p. 10):
"Qean-up on shore is likely to be less complete, more difficult, more expensive, more ecologically
damaging and slower than treatment at sea. There is thus a clear case in favour of the latter.
Mechanical recovery from the sea has many features of the ideal system, but unfortunately it is
only feasible at the present time in calm conditions, needs ancillary equipment and trained
operators and involves high capital costs. For the time being dispersants provide the only really
effective and generally applicable method of dealing with oil at sea. They are most effective and
can be used in smaller quantities when applied to fresh oil, before "weathering" takes place.
Concentrate dispersants increase the effective spraying time of boats and are considerably more
economical than ordinary dispersant."
However, to utilize chemicals as dispersants against oil on the sea surface is to fight
the devil with Beelzebub, as the German saying goes. Up to now authorities in the
Federal Republic of Germany are reluctant to organize large-scale oil spill fighting
equipment based on chemical dispersants, and they are encouraged by public opinion
which at this moment, 1981, is very much against any introduction of chemicals into
the sea; certainly dispersants have to be ranged under pollutants. Experimental evidence regarding the tOxicity of oil and oil-dispersant mixtures to marine life are not
conclusive, and contrary to the British results from short-term toxicity experiments
(Table 19) there are contradicting results from long-term studies (Fig. 53). It seems
necessary to spend more scientific effort on the question, unbiased by industrial
pressure or emotions, to have better arguments regarding the conflict of damage by
dispersants in the open sea versus damage of oil on the shores.
Other chemicals used to fight oil spills are "herders" which counteract the spreading
of the oil at the sea surface and have the effect that oil creeps together to form larger,
water-repellent units, and "sorbents" which bind the oil by capillarity and adsorption. Polyurethane foam may take up oil 30 times its own weight, and can be reused
after pressing the recovered oil out. Straw is a sorbent that takes up oil about five
times its own weight. At the "Torrey Canyon" oil spill, in 1967 the French Government used pulverized blackboard chalk, to sink the already aged oil that approached
the coasts of Brittany. By the use of 3000 t of chalk, approximately 30,000 t of oil
were eliminated from the sea surface. However, is has been reported that in 1969 oil
99