PHOTO 5 The brightest areas of the Earth are the most urbanized, but not necessarily the most populated. (Compare western Europe with China and India.) Cities tend to grow along coastlines and transportation networks. (Image courtesy of NASA.)

NOAA, and EPA should work with industry to develop a more comprehensive database of environmental information and ambient hydrocarbon levels, and should develop and implement a rapid response system to collect in situ information about spill behavior and impacts.

Natural seep systems and sites of historical spills offer good opportunities for field studies of the fate and effect of the release of crude oil and (in the case of spills) refined products, especially to understand dissolution and long-term weathering. Federal agencies, especially the USGS, NOAA, EPA, and MMS, should develop and support targeted research into the fate and behavior of hydrocarbons released to the environment naturally through seeps or past spills.

Effects

Ecosystems and their components vary at time scales ranging from seasons to decades and longer. Therefore, in the absence of ongoing monitoring, it is exceedingly difficult to quantify the effects of oil in the sea, or to establish when recovery from a pollution event is complete. The establishment of monitoring programs in selected regions with an elevated risk of petroleum spills or discharges would enhance the ability to determine effects and recovery and to understand the processes controlling ecosystem responses to pollution. Existing databases on the distribution, frequency, and size of petroleum spills and existing petroleum distribution routes could be used to identify locations most appropriate for monitoring. Federal agencies, especially the USGS and EPA, should work with state and local authorities to establish or expand efforts to monitor vulnerable components of ecosystems likely to be exposed to petroleum releases.

The inputs and long-term fate of land-based sources (due both to runoff and to atmospheric deposition) are poorly understood. The range of uncertainty of land-based runoff of petroleum hydrocarbons is four orders of magnitude. The upper limit, if correct, would dwarf all other inputs. The loads from rivers and air inputs are not being monitored consistently, and the background inputs from rivers are virtually unknown. To assess the impacts attributable to different sources including oil spills and non-point sources, federal agencies, especially the USGS and EPA should work with state and local authorities to undertake regular monitoring of Total Petroleum Hydrocarbon (TPH) and PAH inputs from air and water (especially rivers and harbors) to determine background concentrations.

There are demonstrable effects of acute oiling events at both small and large spatial scales. These effects result from physical fouling of organisms and physiological responses to the toxic components of oil. Although there is now considerable information on the toxicological effects of individual components of oil, there is a lack of information about the synergistic interactions in organisms between hydrocarbons and other classes of pollutants. This problem is particu



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