contained unacceptable concentrations of DDT. The Heyerdahl expedition 

 drifting in midocean between Africa and South America encountered 

 numerous large patches of putrid water, and reported the ocean was 

 "visibly polluted by human activity." The voyage of the tinker Manhattan 

 to the Arctic suggested the need to prepare for possible oil spills in polar 

 regions. Scientists investigating the "Crown of Thorns" starfish whose ex- 

 plosive growth has led to the destruction of Pacific Ocean corals attribute 

 the growth in part to man-induced pollutants and the physical modifications 

 resulting from dredging and blasting which reduced the starfishes natural 



enemies. 



Characteristics of Ocean Pollution 



Pollution of the ocean has several pronounced characteristics. First, it is 

 long lasting. Rivers renew themselves each year and carry pollutants from 

 their course, and lakes can cleanse themselves over decades or centuries. But 

 the ocean is the final depository of pollutants which will remain there for 

 thousands of years. This is particularly true of materials which do not dis- 

 solve or readily break down in water. Lead from gasoline exhaust entering 

 the oceans today will be circulating or deposited on the sea floor centuries 

 from now. 



Some pollutants in the sea may accumulate in the ocean's food chain 

 where they build up in the marine life cycle. Entering the food chain in 

 marsh water from agriculture runoflf, DDT travels through the food chain 

 and accumulates in fish-eating birds in often injurious concentrations. It has 

 interfered with the reproductive cycle of the osprey and peregrine falcon 

 and has been found in large quantities in Antarctic skua, Atlantic and 

 Pacific shearwaters and Bermuda petrels. 



The global ocean is a great circulating system in constant horizontal and 

 vertical motion. Pollutants entering the system may travel long distances 

 over the earth's surface. Pesticides used on the African Continent have been 

 found in the Bay of Bengal and the Caribbean Sea after traveling in the 

 monsoon and the northeast trade winds. Some of the pesticides found in the 

 Great Lake coho salmon appear to have originated far inland. Acetone and 

 butyaldehyde, harmful to life, have been detected in surface waters of the 

 Florida straits, the Mediterranean Sea, and the Amazon estuary. 



Nor is ocean pollution any respector of political boundaries. Like the 

 ocean environment, it reaches the shores of many States and nations. Air 

 and ocean pollutants travel long distances and can menace the ecological 

 balance and environmental quality of nations far from the source. 



Sources of Pollutants 



Pollutants enter the ocean from many sources. The quantity of munici- 

 pal, industrial, and agricultural waste deposited in the ocean is enormous. 

 With urbanization, oceanic waste disposal is increasing, particularly affecting 

 the quality of water near population concentrations and in estuaries. 



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