This Report

1985 Report


Significance of change in estimate

Consumption of Petroleum


Changes in groupings of subcategories make direct comparison with 1985 study impossible.


Land-based (river and runoff)

Municipal & industrial wastes

Significant differences in data quality, assumptions, and methodology make comparison meaningless.

The large numbers suggested by both studies, although not directly comparable, suggest that land-based sources of petroleum pollution to coastal environments is a significant environmental concern at a variety of scales.


Municipal wastes

Grouped with all land-based sources in current report.



Non-refinging industrial wastes

Grouped with all land-based sources in current report.



Urban runoff

Grouped with all land-based sources in current report.



River runoff

Grouped with all land-based sources in current report.


Recreational marine vessels


Not accounted for in 1985 study.

Large number calculated during current study suggests this may be an important source of petroleum pollution, especially given the environmental sensitivity of the coastal areas where these vessels most commonly operate.

Spills (commercial vessels ≥100 GT)

Nontanker accidents

Both studies used national databases as the foundation for the resulting estimate. Thus, the results should be comparable at two significant figures.

The decrease from 20,000 tonnes per year to 7,100 tonnes is significant and reflects the substantial steps taken to reduce the incidence of transportation-related spills worldwide.

Operational discharges (vessels ≥100GT)

Bilge and Fuel oils

Differences in data, assumptions, and methodology make comparison of little value.


Operational discharges (vessels <100GT)


1985 study did not differentiate based on vessel size.


Atmospheric deposition


Differences data, assumptions, and methodology make comparison of limited value.

Large numbers calculated in both studies suggest this may be a significant input of petroleum (especially PAH) to the marine environment

Jettisoned aircraft fuel


Not accounted for in 1985 study.

Large number (7,500 tonnes worldwide) suggests that this source may generate significant loading at local scales.


Ocean dumping

Not accounted for in current study.

Ocean disposal of wastewater treatment/sewage sludge has been banned in the United States and elsewhere, but may be locally significant where practiced. However, given the large uncertainty already associated with estimates of land-based sources (2 orders of magnitude), calculating the additional loads to each region or worldwide from sludge disposal was deemed to be of limited value.

sources of petroleum inputs, is an example of chronic persistence and toxicity beyond the observations made following oil spills. Meador et al. (1995) reviewed the processes controlling the uptake and persistence of PAH in marine organisms, especially under chronic exposure conditions, highlighting differential mechanisms of tissue distribution and elimination. Transfer of contaminants to marine biota and the human consumer and toxicological effects on the ecosystem are dependent on the availability and persistence of these contaminants within benthic environments. The incidence of tumors and other histopathological disorders in bottom-dwelling fish and shellfish from contaminated coastal areas has been suggested as a possible link to chronic hydrocarbon exposure and uptake (Neff and Haensly, 1982; Berthou et al., 1987; also see Chapter 5).

To understand the toxic effects of petroleum hydrocarbon releases to the marine environment, one has to examine the loading of the more toxic components of the hydrocarbon mixture. Since PAH are thought to be responsible for many of the biological effects of petroleum, estimates of PAH

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