Biological Sur\t:y — Genesee River 29 



II. Chemical Investigation of the Genesee River System with 

 Especial Reference to Pollution 



By F. E. Wagner, 



Fellow, Bensselaer Polytechnic Institute 



Inseparabl}' linked with any j^olicy of fish propagation is a 

 study of water conditions, and the effects of natural influences, as 

 well as those of human creation. One of the first questions which 

 arises is that of pollution, and it is with this that the investigation 

 herein reported has been primarily concerned. 



Types of Pollution. — The more noteworthy types of pollution 

 encountered were those chiefly from milk condensaries, cheese fac- 

 tories, oil wells and refineries, paper mills, canning factories, salt 

 refineries, chemical industries, wood products industries, and 

 municipal sewage, with the great variety of contributory elements 

 which the word implies. Naturally these differ in their effects 

 upon fish life, but with all the effects bear a direct relation to the 

 ratio of contaminating material to water receiving it, so that dilu- 

 tion is the great factor. 



Gaseous Relations. — Those materials, such as food products, 

 which are subject to decomposition, consume in decomposing the 

 dissolved oxygen in the w^ater which is necessary for the respira- 

 tion of fish and certain organisms on which they feed. 



The solubility of a gas in water depends upon the temperature 

 of the water, and the pressure of the gas upon it. The maximum 

 quantity of oxygen which a water will take up at any particular 

 temi)erature and barometric pressure is its saturation capacity for 

 those conditions. It follows that when anything occurs within 

 the water, such as respiration or decomposition, tending to deplete 

 the content of oxygen, that the water immediately sets about 

 restoring itself to a condition of saturation, and logically the 

 greater the depletion, the more rapid will be the reabsorption. 

 Neglecting for tlie moment the eff'ect of oxygen producing aquatic 

 plants, or the influx of highly oxygenated tributary waters, this 

 can only be accomplished by reoxygenation from the air, in tw^o 

 different manners. A quiet body, such as a sluggish stream or 

 pond can restore its oxygen only by surface absorption and 

 gradual distribution from upper to low^er strata. The slowness of 

 this restoration can be appreciated by any one who has noted the 

 "flat taste" of recently boiled water. Extremely more rapid 

 reoxygenation takes place when the water is intimately mixed with 

 the air as in a waterfall, natural or artificial, or in the riffles 

 occurring between pools of a rapidly flowing stream. This point 

 is of primary importance in our present investigation because of 

 the nature of the streams, and data will be supplied showing the 

 vast difference between the behavior of a rapid, riffly stream and 

 a sluggish one, both heavily contaminated with decomposible 

 material. 



