TABLE 2-9 Average Annual Input (1990-1999) of Petroleum Hydrocarbons (tonnes) for the Coastal and Territorial Waters of Alaska

ZONE (Coastal)

P

Q

Sum Seeps

400

tracea

Platforms

trace

na

Atmospheric

trace

na

Produced

110

na

Sum Extraction

120

nab

Pipelines

trace

nac

Tank vessel

20

trace

Coastal facilities

30

10

Atmospheric

trace

trace

Sum Transportation

60

20

Land-based

80

traced

Recreational vessels

50

20

Vessels >100GT (spills)

70

trace

Vessel >100GT (Op Discharge)

trace

trace

Vessel <100GT (Op Discharge)

trace

trace

Atmospheric

890

580

Aircrafte

na

na

Sum Consumption

110

600

ZONE (Offshore)

P

Q

Sum Seeps

na

na

Platforms

na

na

Atmospheric

na

na

Produced

na

na

Sum Extractionb

na

na

Pipelinesc

na

na

Tank vessel

trace

trace

Atmospheric

trace

trace

Sum Transportation

trace

trace

Land-basedf

na

na

Recreational vesselsg

na

na

Vessels >100GT (spills)

30

50

Vessel >100GT (Op Discharge)

trace

trace

Vessel <100GT (Op Discharge)

trace

trace

Atmospheric

210

220

Aircraft

45

15

Sum Consumption

290

300

Grand Total

980

910

Sum of Anthropogenic

580

910

aEstimated loads of less than 10 tonnes per year reported as “trace”

bNo known oil and gas production in this region (North Slope production is limited to terrestrial fields)

cNo known coastal or offshore pipelines in this region (North Slope production is limited to terrestrial fields)

dLoad in this region limited to petroleum hydrocarbons derived from eroded source rocks (see Chapter 3 and Appendix I)

ePurposeful jettisoning of fuel not allowed within 3 nmiles of land (see Chapter 3 and Appendix E)

fLand-based inputs are defined in this study as being limited to the coastal zone (see Chapter 3 and Appendix I)

gRecreational vessels are defined in this study as being limited to operations within 3 nmiles of the coast (see Chapter 3 and Appendix F)

ever, the VOC consist mostly of methane and ethane, which tend to oxidize rather than deposit in the oceans. These emissions may represent a “greenhouse gas” concern, but their atmospheric deposition into North American waters is less than 0.5 percent of all inputs, and inputs of VOC into the oceans worldwide are less than 4 percent of the estimated total. The U.S. Coast Guard should work with the International Maritime Organization to assess the overall impact on air quality of VOC from tank vessels and establish design and/or operational standards on VOC emissions where appropriate.

On the basis of limited data, aircraft inputs from deliberate dumping of jet fuel in the sea appear to be locally significant. Federal agencies, especially the Federal Aeronautics Administration (FAA), should work with industry to more rigorously determine the amount of fuel dumping by aircraft and to formulate appropriate actions to limit this potential threat to the marine environment.

Fates

The effect of petroleum hydrocarbon is not directly related to the volume released. It is instead a complex function of the rate of release, the nature of the released hydrocarbon, and the local physical and biological ecosystem. Some progress has been made in understanding the basic processes affecting fates such as evaporation. Much more needs to be learned about oil-sediment interaction, vertical dispersion and entrainment, dissolution, Langmuir cells, and hydrate formation (as related to deep subsurface releases of gas). Furthermore, the priorities for research into petroleum hydrocarbon fate and transport have historically been driven by large spills. Thus, resource allocation to support these efforts tends to wane in periods during which a large spill has not recently occurred. Federal agencies, especially NOAA, MMS, the U.S. Coast Guard, and the USGS, should work with industry to develop and support a systematic and sustained research effort to further basic understanding of the processes that govern the fate and transport of petroleum hydrocarbons released into the marine environment from a variety of sources (not just spills).

Response plans depend heavily on site-specific modeling predictions of the behavior of spills of various sizes and types, under a variety of environmental conditions. There is a need for both better baseline data, including ambient background levels of hydrocarbons in the sea, and better data for calibrating fate and behavior models. Because experimental release of petroleum is not feasible under most circumstances, comprehensive data on the fate of the oil must be collected during spills. Such efforts are generally neglected, because moving needed equipment and personnel to spill sites to collect data is of lower priority than containing the spill and minimizing damage to the environment and property. Federal agencies, especially the U.S. Coast Guard,



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