OIL AND RELATED CHEMICALS - Marine Pollution: What Everyone Needs to Know - page 79

decade. Three years after the spill most of the remaining oil
was in places where it could not degrade, such as below the
surface sediments or under mussel beds. Heavily oiled coarse
sediments protected oil reservoirs below the surface, prevent-
ing oil from weathering in intertidal sites. These sites often
contained fish eggs and other vulnerable organisms. In a cold
environment like Alaska oil degrades much more slowly than
in warmer regions, and salmon embryos developing in the
sediments a decade later still did not develop properly. After
more than a decade, pockets of oil remained in these marshes
where many species continued to show evidence of harm. Fish
embryos continued to be affected by oil trapped in gravel and
sediments many years after the spill.
Can oiled birds and sea otters be rehabilitated?
Marine birds and mammals are the most obvious victims after
spills, since they are large and at the surface of the water. Birds
try to clean up oil on their feathers by preening and end up
swallowing oil, which is toxic to them, affecting their immune
system and making them more vulnerable to disease. Nine
years after the Exxon Valdez spill, most injured populations
had not recovered. Many people have spent a great deal of
time and effort to clean oiled birds and marine mammals after
oil spills. A study of oiled and rehabilitated brown pelicans
found that long-term injury had taken place, and the birds did
not breed or show normal behavior or survivability. A study
of released oiled, oiled and rehabilitated, and unoiled surf
scoters ( Melanitta perspicillata ) after a spill found that scoters
tolerated the rehabilitation process itself well, but they subse-
quently had markedly lower survival than unoiled birds.
How can oil spills be cleaned up?
Considerable expense and effort is associated with attempts
to clean up oil spills, which may take months or even years