356 



attributed to contamination of tlieir food sui)plies by dieldrin. DDT and poly- 

 chlorinated biphenyls. Similar incidents appear to have occurred among marine 

 birds off the coasts of the TJnited States, including disastrous reproductive fail- 

 ures in the marine ecosystems off Southern California. 



d. Radioactive wastes 



Radioactive materials in the marine environment may affect organisms by 

 direct radiation, absorption through body surfaces, absorption through body sur- 

 faces, absorption through cell membranes, and ingestion from food and water 

 supplies. In general, lower organisms seem to be more resistant to ionizing radia- 

 tion than the higher vertebrates ; for example, doses of 25,000-600,000 roentgens 

 may be required to produce 100 per cent mortality among algae, while doses of 

 a small fraction of these levels may produce the same effect among higher verte- 

 brates. However, radioactive substances may concentrate in higher marine 

 life forms by ingestion of contaminated lower organi.sms and might, if deposited 

 on the oceans in .sufficient quantities, render fish and shellfish hazardous for 

 human consumption. The presence of significant amounts of radioactive materials 

 in the marine environment might also lead to long-term genetic effects on its 

 life forms. 



A number of studies were conducted in the 1950's and 1960's to determine the 

 condition under which low-level radioactive wastes might be dumped in the 

 oceans without serious ecological danger. These studies suggested criteria related 

 to such factors as the quantity of isotopes dumped in curies per year, the con- 

 centration in seawater. the depth of the disposal area, the limiting depth of human 

 food organisms, and the characteristics of the bottom, surrounding waters and 

 benthic life forms. 



e. Biological and chemical irarfare agents 



These agents are of course designed to produce highly toxic or debilitating 

 effects on humans or other terrestrial life forms. Their effects in the marine 

 environment are very difficult to assess, and would vary tremendously, depending 

 on the particular pathogen or chemical agent involved. Many chemical agents 

 might produce severe localized toxic effects, but be neutralized fairly rapidly in 

 the marine environment and produce no long-term effects ; others may have great 

 potential for long-term damage. Similarly, many biological agents might be ex- 

 pected to die quickly in saltwater, but any adaptive pathogen capable of complet- 

 ing a life cycle in the ocean environment might create very serious and wide- 

 spread biological disruption. While it is, therefore, impossible to generalize about 

 the effects of these agents on the oceans, it is safe to say that many agents may be 

 expected to have serious potential for environmental disruption. 



/. Other chemical compounds 



The environment impact of several other groups of potentially toxic chemical 

 compounds is not well known. Cyanides are among the most toxic of all indus- 

 trial chemicals, and when directly ingested or inhaled in sufficient amounts may 

 produce almost instantaneous collapse and respiratory cessation. Their effects 

 in the marine environment are not we'l understood ; however, relatively small 

 concentrations may inhibit growth and have toxic effects on fish, but lower 

 organisms seem more resistant to cyanide concentrations. Fluorides, when 

 ingested in sufficiently high quantities, may also be toxic to humans, and in 

 concentrations of hundreds of milligrams i>er liter may injure or inhibit the 

 growth of terrestrial plants : on the other hand, moderate amounts in drinking 

 water may have beneficial effects on human health. There is also limited data on 

 the environmental effects of organosilicons ; organosilicon ethers and esters may 

 be toxic if inhaled, but polymeric silicons are relatively non-toxic and biologically 

 inert. 



Finally, as an overall comment not limited to a particular substance, the 

 CEQ report of 1970 on Ocean Dumping noted that "in laboratory experiments 

 with polluted .sediments from the New York Bight dispo.sal area, the following 

 sublethal effects were shown : 



"Serious infections were found in native species. 



"Bottom waters inhibited phytoplankton cell growth and division. (34) 



"Lethal and sublethal effects from toxic wastes are complex and not well 

 understood. But evidence is mounting that these effects may be widespread and 

 very harmful to the marine environment. Their potential for deferred and long- 

 range ecological damage must be taken into account in any program to control 

 ocean dumping." 



