Not So Slick When Oil
Ends Up In The Sea
29 million gallons of petroleum enters the oceans
off North America each year, shows a new study by
the National Research Council. The report finds
that about 85 percent of that pollution can be blamed
not on massive oil spills, but on the lesser amounts
released by airplanes, swept into polluted rivers
and from the largest culprits: recreational boats
and runoff from the land.
amount of petroleum released into North American
and global waters is less than previously thought,
the committee found. At the same time, however,
new studies show that the environmental effects
of a major oil spill are longer lasting than once
thought and that even small amounts of petroleum
can seriously damage marine life and ecosystems.
spills can have long lasting and devastating effects
on the ocean environment, but we need to know more
about damage caused by petroleum from land based
sources and small watercraft since they represent
most of the oil leaked by human activities,"
said James Coleman, chair of the committee that
wrote the report.
doesn't mean we can ignore hazards from drilling
and shipping, however," Coleman cautioned.
"Although new safety standards and advances
in technology reduced the amount of oil that spilled
during extraction and transport in the last two
decades, the potential is still there for a large
spill, especially in regions with lax safety controls."
47 million gallons seep naturally from the seafloor
into the North American oceans, more than all human
sources of petroleum pollution combined. That puts
North America in a better position than the world
as a whole: worldwide, about 210 million gallons
of petroleum enter the sea each year from human
caused petroleum sources, with an additional 180
million gallons coming from natural seepage, the
the human caused petroleum pollution entering the
oceans around North America, less than eight percent
comes from oil tanker or pipeline spills, says the
report by the National Academies' National Research
Council (NRC), titled "Oil in the Sea: Inputs,
Fates, and Effects."
report, which relies on data from a variety of sources,
is said to be far more accurate than the NRC's last
such assessment in 1985.
slicks visible from the air and birds painted black
by oil get the most public attention, but it is
consumers of oil -- not the ships that transport
it -- who are responsible for most of what finds
its way into the ocean, the NRC says.
exploration and extraction are responsible for only
three percent of the petroleum that enters the sea,
with their effects concentrated where oil drilling
rigs are at work in the Gulf of Mexico and in waters
off southern California, northern Alaska, and eastern
bulk of the 29 million gallons from humanmade sources
comes from individually small source that, combined,
account for about 25 million gallons of ocean petroleum
example, oil runoff from cars and trucks is increasing
in coastal areas where the population is growing
and roads and parking lots are expanding. More than
one half of the land based oil contamination along
the North American coastline occurs between Maine
and Virginia, where there are dense seaside populations,
many cities, several refineries, and high energy
use, the report notes.
polluted by oil in wastewater or the improper disposal
of petroleum products are also a major source of
oil entering the sea.
two stroke engines still found on many recreational
boats and jet skis were purposely designed to discharge
gasoline and oil. Land runoff and recreational boating
account for nearly three-quarters of the petroleum
released into the sea each year through human consumption.
sources of oil from human activities include military
and commercial jets that occasionally jettison excess
fuel over the ocean and ships that release oil from
their engines while in port or at sea.
impact of an oil spill on marine life is not directly
related to the size of the spill, since even a small
spill in an ecologically sensitive area can have
long term impacts, the NRC found. A spill's influence
also depends on the type and amount of toxics present
in the petroleum product being released.
riskiest toxics are a class of organic compounds
known as polycyclic aromatic hydrocarbons, or PAHs.
Growing evidence suggests that PAHs and other toxic
compounds can have adverse effects on marine species
even at very low concentrations. This means chronic
releases from runoff and recreational boating may
inflict more damage than previously thought, and
that the effects of large spills may last as long
as residual oil persists in the area.
of Mexico Impacted
Gulf of Mexico is the most heavily impacted of North
America's ocean waters, the NRC learned. About 20
percent of the land based petroleum entering North
American coastal waters ends up in the Gulf of Mexico.
Gulf also receives most of the oil and gas that
is emitted by recreational boats and jet skis, and
oil drilling rigs concentrated in the Gulf spill
thousands of gallons each year.
amount of petroleum released during oil drilling
has dropped in recent years, but the threat of a
spill cannot be ignored, the NRC warns. The report
recommends that the U.S. Minerals Management Service
promote extraction techniques that minimize accidental
or intentional releases of petroleum.
federal agencies, including the Department of Transportation
and the U.S. Environmental Protection Agency (EPA)
should also continue to work with state environmental
agencies and industry to minimize the potential
for spills from pipelines and other coastal petroleum
new shipping standards have helped reduce oil spills
and deliberate discharges from tankers and other
ocean going vessels, about 2.7 million gallons of
petroleum still spill into North American waters
while being transported to market. The report cautions
that large tanker spills are still possible, particularly
in areas without stringent safety procedures and
better monitor how much oil consumers and industry
are depositing in the ocean, the NRC recommends
that federal agencies work with state and local
environmental bureaus to develop a system for documenting
sources of runoff. The report also calls on the
EPA to continue efforts to phase out older, inefficient
two stroke engines, which power many jet skis and
other small watercraft.
report also says federal ocean management agencies
should try to develop more accurate techniques for
estimating the amount of oil that seeps into the
ocean from geologic formations beneath the seafloor.
This would help researchers distinguish the effects
of petroleum released by natural processes versus
human activities, and study how marine life responds
to the introduction of oil.
oil seeps naturally into the ocean, local marine
ecosystems have been altered, the report says. For
example, in seepage areas in the Santa Barbara Channel
off California, there is little biodiversity, with
just bacteria and a few invertebrate species surviving
in the petroleum slurry.
conducted in the wake of the EXXON Valdez spill
in 1989 shows that large oil spills can be devastating
to the marine environment. They kill fish, mammals,
birds and their offspring, destroy plant life, and
reduce the food supply for organisms that survive.
also disrupt the structure and function of marine
communities and ecosystems, although more research
is needed to better understand how spills affect
overall populations, the NRC says.
is known about how chronic releases from sources
such as land runoff and inefficient two stroke engines
on boats and jet skis affect marine ecology. The
report calls for the federal government, in cooperation
with academia and industry, to launch a major research
effort aimed at better understanding how chronic
releases of petroleum affect the marine environment,
particularly when organisms in already polluted
waters are exposed to the multiple toxics found