331 



ment and the biota living there have not been exposed to the stresses which are 

 characteristic of the coastal zone environment. It is possible that disposal in 

 the deep sea may have much more drastic effects on this biota than has been 

 observed with the hardier forms living under continual stress. As mentioned 

 above, evidence is accumulating that the rate of decomposition of organic mate- 

 rials under the low temperature and high pressure conditions of the deep sea 

 is much slower than it is at normal pressure even at the same low temperature. 

 Disposal in the deep sea may, therefore, be merely a mechanism for preserving 

 our waste materials for posterity. We certainly need to know a great deal more 

 about the sensitivity of the biota of the deep sea to this type of pollution before 

 millions of dollars are spent on pipelines or barges to contaminate the area, 



c. Toxic materials 



Toxic materials are becoming common in the coastal zone environment but 

 very few studies have been made concerning the resistance of marine organisms 

 and populations to these toxins. A continuing study is needed to evaluate the 

 toxic effects of heavy metals and of the wide variety of organic compounds. 

 Long-term effects, especially on breeding and behavior of organisms may be 

 particularly important but are almost unknown. These problems are intensified 

 because we are producing new organic compounds at the rate of several hun- 

 dreds per year and many of these are reaching the environment with unknown 

 consequences. 



There is adequate evidence that unsuitable levels of mercury contamination 

 are present in all of our aquatic environments. Lakes, rivers, streams and estu- 

 aries have been extensively closed to the harvesting of fish and shellfish because 

 the mercury levels in the flesh exceeds the amounts recommended by the Food 

 and Drug Administration. The Minamata disease in Japan demonstrated clearly 

 that the organic compounds of mercury are particularly hazardous. 



Extensive studies have also been made of the distribution of lead in the oceans. 

 As a result of the burning of tetraethyl lead in gasoline, the lead content of the 

 surface water of the world ocean has been increased substantially in recent 

 decades. Less adequate information is available about the many other toxic 

 heavy metals which are produced and discharged in large amounts by our in- 

 dusitrial technology. 



The organic compounds are particularly troublecome. The effects of DDT on 

 the breeding failure of oceanic bird populations is amply documented. There is 

 also evidence that DDT can effect the rate of photosynthesis of several species 

 of marine phytoplankton. The distribution of DDT and its derivatives in the 

 marine ecosystem is, however, very poorly known so that one cannot even esti- 

 mate the proportion of the total DDT produced which has reached the ocean 

 reservoir. Even if we knew how much is there, we do not have any evidence 

 concerning its persistence in the marine environment. Even less is known about 

 the distribution of the highly toxic polyehlorinated biphenyls, but we now 

 know how to identify and measure these and the evidence so far available indi- 

 cates that they may be as broadly distributed in the environment as DDT and 

 its derivatives. 



d. PetrochemiGals 



Although oil contains several toxic materials, and could have been discussed 

 with the other toxic organic materials, it deserves a special mention because 

 of the magnitude of sea transport of oil. In an energy-based civilization, trans- 

 portation of oil by tankers is certain to increase in coming years. I^arger and 

 larger tankers are being designed and built and an accident to one of the huge 

 super tankers would have much broader efi'ects than the accidental releases of the 

 past. Although there are laws and international compacts concerning the dis- 

 charge of oil at sea, they are more frequently ignored than obeyed. 



There are many aspects of oil spills which require more intensive investiga- 

 tion. There is considerable need for more intensive studies of containment and 

 recovery of the oil following an accident, an aspect of the problem which might 

 well be considered by our Department of Ocean Engineering in cooperation with 

 some of the engineering groups at M.I.T. From an ecological point of view the 

 use of detergents to disperse the oil merely makes it more available to the marine 

 biota, and some of the detergents which have been used are more toxic than the 

 oil itself. Also efforts at sinking the oil to the bottom merely moves the problem 

 to another location where the toxic effects may have just as drastic and serious 

 results. Intensive studies on all of these problems are needed. 



