DISCUSSION 



The purpose of the experiments described in this report was to 

 find out whether crude oil and other oils, combined with carbonized 

 sand and sulsnerged to the bottom, are toxio to marine life. The 

 tests, made with various organisms commonly fovmd in the environment 

 where oil pollution is apt to occur, were designed to answer this 

 particular question. We made no attempt to study the chemical nature 

 of the toxic substance or substances leached flrom oil, the rate of 

 their leaching, and the stability of these substances in sea water. 

 The study of these important problems is impossible without special 

 funds, personnel, and equipment which were not available. We hope, 

 however, that the results of our bioassays, which show the toxio effect 

 of various types of oil on marine organisms, will stimulate such ein 

 investigation. Rapid development of the oil drilling operations in the 

 inshore waters and the extension of explorations for new oil fields to 

 the offshore areas of the continental shelf indicate the necessity and 

 urgency of toxicological studies of crude oil and oil wastes. Sound 

 national policy of conservation demands that the development of mineral 

 resources should not spell the doom of destruction to the inshore and 

 coastal fisheries,- the products of irtiich are needed for the welfare of 

 millions of people. Control of pollution is, therefore, a very urgent 

 problem whioh demands immediate action. 



Our experiments confirm .previous findings made by us and others 

 that oil added to sea water results in a toxio environment to marine 

 animals. The hydrosoan Tubularia crocea , one of the more sensitive 

 organisms of shallow waters, was quickly killed if placed in water 

 containing relatively small amounts of water extract of oil. Likewise, 

 Tubularia perished If a mixture of oil and carbonized sand was placed 

 near the colony. The lethal effect of such a mixture was noticeable 

 even when sea water was steadily flowing through the container. 



Different results were obtained, however, in the tests in whioh 

 the oil and sand mixture was not in the immediate vicinity of Tubularia 

 but was introduced Into the containers from which the water was fed to 

 the finger bowls with this hydrold. Under these conditions no toxic 

 effect was observed, presumably because of greater dilution and the 

 failure of substances leached from the oil to reach threshold concentrations. 



The toxicity of oil and carbonized sand mixtures was also demonstrated 

 in experiments with adult barnacles, Balttnus ' balanoides ; embryos of the 

 toadfish Opsanus tau ; and the eastern oyster, Ostrea virglnica. No 

 toxic effect was apparent in the experiment witli the hard shell clam, 

 Venus mercenarla . It seems probable that in the latter test the poisonous 

 extractives of oil were in too dilute concentration to produce an effect 

 under the conditions of the experiment* 



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