32 New Yokk State 



releasing poisonous products. The stream, originally characterized 

 by an abundance of clear, pure-water animals, is so modified that it 

 can afford existence only to those which live in a polluted environ- 

 ment. Furthermore, the possibility of fish reproduction is very 

 definitely interfered with, for the eggs that are deposited sink into 

 the sawdust or are covered by it with the shifting of the bottom by 

 the current. Those fish eggs which are abandoned and must depend 

 upon chance for their development are unfortunately suffocated. 

 Even those eggs which are watched by the adult fish, so that the 

 nests are kept from being covered by the floating sawdust, find 

 the water unfavorable for development and die off in large numbers. 

 Finally the fry, if any hatch, seek in vain for food and shelter. 

 Valuable fishing in both lakes and streams has been totally destroyed 

 in this way* 



From the tanneries are discharged large amounts of carbonate 

 of lime, which settles over the bottom in the form of a white film 

 that is inimical to the smaller organisms of the water and apparently 

 to the fish also. The wastes of steel mills are similarly deposited 

 in characteristic form on the stones and gravel of the bottom. While 

 here the character of the fluid wastes themselves is promptly destruc- 

 tive to aquatic life, because o ftheir acid character, so that the 

 deposit itself is of lesser significance, nevertheless it plays some 

 part and is of especial sigificance in retarding the recovery of the 

 stream. 



Wastes which are discharged from oil refineries are particularly 

 inimical to aquatic life. They frequently form a firm adhesive 

 film, covering the stones, bottom, and all other objects in the water. 

 This covering seems to be a thin layer of tar, and is very resistant, 

 so that even after the cause of the pollution has been removed, 

 there remain visible signs of the pollution for a long time. These 

 wastes are so resistant that it is difficult to find any way to purify 

 them and no type of industrial waste is more serious to aquatic 

 life. Such wastes come from gas plants as well as from oil refin- 

 eries, and are unfortunately widely disseminated. The serious char- 

 acter of their influence is vividly shown by field studies in a region 

 where they are discharged into a stream. Many observers have seen 

 a beautiful little brook rich in fish and other aquatic life trans- 

 formed into a barren, unsightly, stinking stream, merely by the addi- 

 tion of wastes from a small town gas plant. The experimental data 

 confirm these observations fully and should be cited here in part 

 that the matter may be clearly comprehended. 



