the addition of any heat of artificial origin should not 

 be raised by more than 4 F during the fall, winter, and 

 spring (September through May), or by more than 

 1.5 F during the summer (June through August). 

 North of Long Island and in the waters of the Pacific 

 Northwest (north of California), summer limits apply 

 July through September, and fall, winter, and spring 

 limits apply October through June. The rate of tem- 

 perature change should not exceed 1 F per hour except 

 when due to natural phenomena. 



Suggested temperatures are to prevail outside of 

 established mixing zones as discussed in the section on 

 zones of passage. 



coastal waters shall not be less than 5.0 mg/1, except 

 when natural phenomena cause this value to be de- 

 pressed. 



(2) Dissolved oxygen concentrations in estuaries 

 and tidal tributaries shall not be less than 4.0 mg/1 

 at any time or place except in dystrophic waters or 

 where natural conditions cause this value to be de- 

 pressed. 



The committee would like to stress the fact that, due 

 to a lack of fundamental information on the DO re- 

 quirements of marine and estuarine organisms, these 

 requirements are tentative and should be changed when 

 additional data indicate that they are inadequate. 



Dissolved oxygen 



Dissolved oxygen requirements of marine orga- 

 nisms are not as well known as those for freshwater 

 forms. Studies have been made indicating that 

 minimum dissolved oxygen concentrations of 0.75 

 to 2.5 are required for test species to resist death 

 for 24 hours. Most marine species died when the 

 dissolved oxygen dropped below 1.25 mg/1 for a 

 few hours. Reduced swimming speed and changes 

 in blood and serum constituents occurred at dis- 

 solved oxygen levels of 2.5 to 3 mg/1. It was 

 foimd that DO levels between 5.3 and 8 mg/1 were 

 satisfactory for survival and growth. Levels above 

 17 mg/1, however, produced adverse effects. Large 

 fluctuations in dissolved oxygen from 3 to 8 mg/1, 

 diurnal or otherwise, produced significantly more 

 physiological stress in fishes than fluctuations from 



3 to 6 mg/1. In tests made to date, it has been 

 found that 5 to 8 mg/1 of DO is apparently suffi- 

 cient for all species of fish for good growth and 

 general well being. It is generally recognized that 

 in deeper waters DO values are often considerably 

 less than 5.0 mg/1. In estuaries where there is a 

 reduction in salinity, levels may drop to as low as 



4 mg/1 at infrequent intervals and for limited pe- 

 riods of time. It is probable that many marine ani- 

 mals can live for long periods of time at much 

 lower levels of DO. Experimental studies with 

 freshwater organisms have demonstrated, how- 

 ever, that low concentrations of DO at which adult 

 fishes can live almost indefinitely, can inhibit feed- 

 ing and growth. In determining DO requirements, 

 it is essential to consider growth, reproduction, 

 and other necessary life activities. 



Recommendation: For the protection of marine re- 

 sources, it is essential that oxygen levels shall be suffi- 

 cient for survival, growth, reproduction, the general 

 well-being, and the production of a suitable crop. To 

 attain this objective, it is recommended that dissolved 

 oxygen concentrations in coastal waters, estuaries, and 

 tidal tributaries of the Nation, including Puerto Rico, 

 Alaska and Hawaii, should be as follows: 



(1) Surface dissolved oxygen concentrations in 



Crude oil and petroleum products 



The discharge of crude oil and petroleum prod- 

 ucts into estuarine and coastal waters presents spe- 

 cial problems in water pollution abatement. Oils 

 from different sources have highly diverse proper- 

 ties and chemistry. Oils are relatively insoluble in 

 sea and brackish waters and surface action spreads 

 the oil in thin surface fihns of variable thickness, 

 depending on the amount of oil present. Oil, when 

 adsorbed on clay and other particles suspended in 

 the water, forms large, heavy aggregates that sink 

 to the bottom. Additional complications arise 

 from the formation of emulsions in water, leach- 

 ing of water soluble fractions, and coating and 

 tainting of sedentary animals, rocks, and tidal 

 flats. 



Principal sources of oil pollution are numerous. 

 Listed in order of their destructiveness to ecosys- 

 tems, they are : 



(1) Sudden and uncontrolled discharge from 

 wells towards the end of drilling operation. 



(2) Escape from wrecked and submerged oil 

 tankers. 



(3) SpiUage of oil during loading and unload- 

 ing operations, leaky barges, and accidents 

 during transport. 



(4) Discharge of oil-contaminated ballast and 

 bilge water into coastal areas and on the 

 high seas. 



(5) Cleaning and flushing of oil tanks at sea. 

 On the average, a ship's content of such 

 wastes is estimated to contain 2 to 3 per- 

 cent oil in 1,000 to 2,000 tons of waste. 



(6) Spillage from various shore installations, 

 refineries, railroads, city dumps, garages, 

 and various industrial plants. 



Spillage From Wrecked Oil Tankers 



Even though wrecks of oil taiikers along the 

 Atlantic coast and subsequent spillage of oil into 

 the sea have been reported several times, no thor- 



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