EFFECT OF OIL POLLUTION ON MARINE AND WILD LIFE 175 



coastal water being affected to some extent. Conditions, in general, 

 were at their worst during and immediately following the war, wncn 

 pollution was undoubtedly at its height. The authors are lea to De- 

 lieve that, on the whole, conditions during 1922 were somewnat oetier 

 than in the preceding year. 



While it is possible that considerable destruction of wild bird life 

 may be chargeable to pollution of waters by heavy oil and tarlike 

 deposits, the authors are of the belief that oil pollution is only partly 

 responsible for the losses in the fish and shellfish industries. In the 

 waters adjacent to the important industrial centers it is believed that 

 these losses will be found to be due as much to other industrial 

 wastes as to oil. 



OIL POLLUTION AND CONSERVATION OF FOOD RESOURCES 



An excellent picture of the effect of pollution on all forms of 

 aquatic life in coastal waters is contained in a paper " by Dr. Thurlow 

 C. Nelson, of Rutgers College, New Brunswick, N. J., read before 

 the laboratory section of the American Public Health Association 

 at San Franscisco, Calif., on September 13, 1920. 



Doctor Nelson states that the effects of human wastes and of trade 

 eftiuents upon a body of Avater are entirely different. Domestic sew- 

 age usually contains little or nothing that is toxic to aquatic organ- 

 isms. Putrefactive and other bacteria, aided by a host of animal 

 forms, decompose the sewage and render it available as plant food. 

 Tlie resulting stimulation of plant growth is followed by an increase 

 in numbers and often in size of the animals that feed upon them. 

 Shellfish growing in waters contaminated with human wastes are 

 therefore usually very fat, oAving to the presence of great numbers of 

 food organisms which in turn are deriving their nutriment from the 

 products of decomposition of the sewage. 



The wastes from factories and manufacturing plants of all kinds 

 present an entirely different problem. Here we are dealing with 

 eftiuents which, in general, are highly toxic to aquatic organisms. 

 For convenience these wastes may be divided into four classes: (1) 

 Acid or alkaline, (2) oil and oil waste, (3) various chemical sub- 

 stances in solution, and (4) precipitates held in suspension. Doctor 

 Nelson goes on to point out that oil, by spreading a film over the sur- 

 face of the water or by coating animals and plants with an impene- 

 trable layer, ultimately kills them, either by direct contact or by pre- 

 venting free interchange of oxygen and carbon dioxide. It is stated 

 that a film of oil on the surface of the water will kill molluscan 

 larvae within a few hours, owing largely to the habit of these organ- 

 isms of swimming close to the surface. In the opinion of this writer 

 the. disposal of industrial wastes in such a way as to render the ef- 

 fluents harmless when emptied into a stream and still not impose an 

 undue tax upon the industries concerned is a problem that will re- 

 quire the best efforts of chemists and engineers for years to come. 



REPORTS ON OIL POLLUTION FROM VARIOUS SOURCES 



During the course of this investigation, which was conducted along 

 the coast from Boston, Mass., to Galveston, Tex., the authors held a 

 large number of interviews and received many communications. 



8 " Some aspects of pollution as affecting oyster propagation." 



