Cotton 1971). 



Oil pollutants have been detected in sedi- 

 ments, water, and organisms in areas of large 

 oil spills as well as from areas where no large 

 spills have occurred in past months or years 

 (Farrington 1977). These areas are near 

 sources of small spills and chronic inputs. No 

 more than an estimated 300 analyses for pe- 

 troleum pollutants in sediment, water, and or- 

 ganism samples have been reported in the lit- 

 erature exclusive of reports of visible sheens 

 on the water. 



The scarcity of published measurements of 

 the extent and severity of oil pollution in sedi- 

 ments and organisms is probably related to 

 the difficulty of making meaningful analytical 

 measurements to detect petroleum pollution 

 (Goldberg 1972). 



Sources of Oil in 

 United States Waters 



The amount of oil entering the marine envi- 

 ronment from known sources has recently 

 been estimated on a worldwide basis 

 (5.3 million metric tons) as well as for the 

 United States (1.3 million metric tons; Na- 

 tional Academy of Sciences 1973, 1975a; Far- 

 rington 1977). 



The largest amounts of oil come from 

 normal transport and refining operations and 

 are intentional discharges (Farrington 1977). 

 Accidents account for only 3% of the oil that 

 reaches marine waters of the United States 

 and for only 5% of the world total. Oil tanker 

 operations account for 26 times as much oil as 

 offshore production in the United States and 

 24 times as much in the world total. 



The oil that reaches the coastal waters from 

 rivers and from land operations accounts for 

 65% of the total (Farrington 1977). The oil 

 that reaches the oceans from the air, by dry 

 fallout and rain, is estimated to be less than 

 5% of the total. 



The relative importance of the various 

 sources of oil entering the marine environ- 

 ment varies with location and time (Farring- 

 ton 1977). For example, a large well blowout 

 would introduce a massive amount of oil to a 

 given location and even if averaged over a 10- 

 year period would be the dominant source for 

 that geographical location. 



The effect of the oil from the various 



sources can be very different (Farrington 

 1977). For example, accidental spills may 

 have both immediate acute effects and long- 

 term chronic effects. Municipal or industrial 

 effluents, in contrast, may have no measur- 

 able immediate impact but may have long- 

 term chronic effects as the concentration of 

 the petroleum chemicals builds up in the 

 ecosystem. 



Two important points relate to control of oil 

 pollution discharges (Farrington 1977): 



(1) The largest source is the chronic drib- 

 bling of oil into the coastal zone by industrial 

 and municipal effluents, urban runoff, and 

 river runoff carrying oil from inland areas. A 

 substantial amount of oil, therefore, will be 

 discharged to the coastal zone regardless of 

 source. This amount will increase as oil con- 

 sumption increases unless control steps are 

 taken. Evidence suggests that chronic low- 

 level pollution could be potentially more dam- 

 aging to ecosystems than isolated cata- 

 strophic spills (Evans and Rice 1974). 



(2) It may be safer for the total marine envi- 

 ronment to drill and produce oil in offshore 

 areas than to import equal quantities of oil. 

 Approximately 0.014% of the oil produced 

 offshore is discharged to the marine environ- 

 ment, in contrast to about 0.16% of the oil 

 transported by tanker. However, this does 

 not take into account the ecological damage 

 that may occur in coastal areas as a result of 

 the construction and maintenance of pipelines 

 and onshore facilities. 



Mystery oil spills, those of unknown source, 

 account for 30% of the oil spills in U.S. waters 

 (National Academy of Sciences 1973, 1975a). 

 There are two possible ways to identify mys- 

 tery oil spills. The first method is to tag oil 

 tanker cargoes, pipeline loads, and storage 

 tank contents with microscopic spheres or 

 special chemicals. However, the size of the bu- 

 reaucracy necessary to ensure accurate rec- 

 ords renders this method impractical (Far- 

 rington 1977). 



The second method is to make detailed 

 chemical analysis of the spilled oils and poten- 

 tial sources. The chemical characteristics are 

 then compared and the best match of a poten- 

 tial source with the spilled oil is attempted. 

 This technique, which is called "passive 

 tagging," makes use of the unique chemical 

 composition of each oil to distinguish one 

 from another and to match oils from source 



