Biological Survey — Oswego Watershed 133 



VI. BIOLOGICAL STUDIES OF POLLUTED WATERS IN 

 THE OSWEGO WATERSHED 



By P. W. Ci.aassen, 



Professor of Biology, Cornell University 



and 



N. L. Cutler, 



Biologist and Sanitarian, N. Y. State Conservation Department 



The object of this investigation was to determine the types of 

 pollution present in the Oswego watershed ; the exact location or 

 source of each case of pollution ; a study of the plants and animals 

 which are found in polluted water and a study of the extent of 

 pollution present with a view of determining what effect the var- 

 ious types of wastes have upon fish and other fresh water organ- 

 isms which normally inhabit clean waters. 



Unlike the conditions which exist in the Genesee river system 

 where the pollution centers are almost uniformly distributed over 

 the entire watershed we find that in the Oswego watershed the head 

 waters are remarkably free from pollution. Here the pollution 

 areas are largely restricted to the industrial centers and the larger 

 cities and villages along the outlets of the Finger lakes and along 

 the streams below the lakes. 



Economic changes during the last ten years have brought about 

 these conditions, for we find in the headwaters of the Oswego 

 watershed a great number of old creameries and milk plants 

 which have ceased to operate. Most of these plants were located in 

 small fresh water streams and constituted one of the chief sources 

 of pollution to the small fishing streams. The milk from these com- 

 munities is now largely hauled by trucks to the cities where it is 

 bottled or turned into various manufactured products. This, to- 

 gether with a natural increase in the size of cities and villages and 

 the establishment of more industrial plants, has increased the 

 pollution problem in these centralized areas. The only redeeming 

 feature which can here be mentioned is the fact that these indus- 

 trial centers are nearly all located on large streams or lakes where 

 the large volume of water is able to absorb much of the polluting 

 substances. 



The types of pollution found in the Oswego watershed may be 

 grouped as follows: domestic sewage, paper mill wastes, woolen 

 mill wastes, milk wastes, cannery wastes, oil, sulphur and various 

 industrial wastes. 



Sewage. — Sewage forms one of the chief sources of pollution 

 in this watershed. The effect of the entrance of raw sewage into a 

 stream is to produce first what is known as a * * zone of recent pollu- 

 tion. ' ' Here the dissolved oxygen supply of the stream is lowered 

 perhaps 20-50 per cent and fresh water organisms, such as green 

 algae, mayfly and stoneny nymphs give way to more tolerant, and 

 even pollutional forms, such as blue-green algae (Oscillatoria), 

 sewage fungus (Sphaerotilus and Leptothrix) and sludge worms 



