• Each year, millions of
gallons of oil are released
into the environment, either
accidentally or intentionally.
– Tanker accidents or
– Spills at offshore drilling rigs
– Run-off and dumping waste
oil from cities and industries.
• In 1979, a huge blowout occurred
at the Ixtoc I oil well in the
southern Gulf of Mexico.
– Over 184 million gallons of oil leaked
into the environment.
– Took 8 months to cap the well
As horrendous as that seems, releases from offshore
wells during normal operations and during
transportation of the oil add much more oil to the
environment than such occasional accidents.
• Oil tanker accidents account for about 10
to 15 percent of the annual input of oil
into the world’s oceans
• Leaks at wells
• Purging of tanks
• Seepage from natural sources
• Castillow de Bellver (1983) caught fire and
relased 78.5 million gallons of ocean off the
coast of Capetown, South Africa
Exxon Valdez (1989) hit a reef and released
about 11 million gallons of oil into the Prince
William Sound of Alaska. The spill was the
largest in U.S. history. Capt. Joe Hazelwood,
who later admitted to having had several
alcoholic drinks that day, (From Huntington,
Long Island). In jail NOW!
– More than 33,000 seabirds, 1,000 sea otters, 100
bald eagles killed.
How much damage is done?
• The type and amount of damage
from an oil spill depend on a
number of factors:
– Type of oil (crude oil most toxic
due to benzene and toluene)
– Weather conditions
– Types of organisms in the area
– Oils spill cleanup is difficult and
EXPENSIVE. It is very difficult to
save animals who have ingested
the hydrocarbons into their digestive
tracts, especially aquatic birds who
preen to insulate themselves.
• On March 24, 1989, an oil tanker struck
Bligh Reef in Prince William Sound,
Alaska, releasing more than 200 million
liters (11 million) of oil.
The map outlines the oil-spill front as it
expanded from 1 to 8 days after the
spill; it was compiled from aerial
observations by the National Oceanic and
Atmospheric Administration, Exxon, the
U.S. Coast Guard, and the Alaska
Department of Environmental
Bottom sediments studied by the USGS
more than 7 weeks after the spill
contained no clear evidence of oil
pollution; possible traces of
contamination were found near the south
end of the Sound, but the presence of oil
could not be confirmed.
Much of the oil was carried onshore by
surface currents and deposited along the
beaches. Long-term monitoring is
needed to assess the effect of the spill
on the marine environment.
So how do we clean it up?
• Containment and
• Application of
1. Enzymes released by the
microbe break the
contaminant down into
2. The contaminant is
consumed as food by the
3. Harmless biological wastes
are all that remain of the
• In the aftermath of the Exxon Valdez incident,
Congress passed the Oil Pollution Act of 1990,
which required the Coast Guard to strengthen its
regulations on oil tank vessels and oil tank
owners and operators. Today, tank hulls provide
better protection against spills resulting from a
similar accident, and communications between
vessel captains and vessel traffic centers have
improved to make for safer sailing.