September 24, 1920] 



SCIENCE 



281 



cem in the practical use of the waters until 

 it is realized that the same activity gives to 

 water its disposal capacity. Without it, 

 waste matters aeciunulating from the sources 

 would render the stream unusable below. By 

 the suitable adjustment of all factors, there- 

 fore, can its greatest benefits be derived. 

 Only imder the most exceptional circimi- 

 stances are we justified in sacrificing all other 

 uses merely to the carrying capacity of the 

 fluid. By jealously guarding its quality and 

 developing its useful capacity the increased 

 burden from commimities and industries can 

 be prepared for. 



INJURIES TO QUALITY VALUE 



The various ways in which the quality 

 value of water may be injured are as diverse 

 as its many uses. Potability, where essential 

 for public water supply, takes precedence over 

 all other uses, and infection becomes the most 

 dangerous injury to water. Though indus- 

 trial waste seldom in itself carries infection 

 it may in other ways by giving disagreeable 

 odors, unpalatable taste, or objectionable color 

 and appearance, render it unfit for drinking 

 purposes. Furthermore, it may render puri- 

 fication difficult, thereby overload filtration 

 the health of the community rests; or it may 

 so hinder the proper functioning of sewage 

 disposal plants as to place such a burden on 

 the stream as to make it an impossible supply 

 for the community. Less important, but 

 more obvious, it is necessary for each industry 

 to have an abundant supply of water rela- 

 tively free from particular substances. For 

 wool scouring it is lime salts; for the manu- 

 facture of fine paper it is discoloring mate- 

 rial ; and so with each industry there are some 

 substances to be avoided. This often deter- 

 mines the location of an industry, and though 

 it may be possible to treat the water in many 

 instances, preventive measures where small 

 concentrations entail widespread injury may 

 be the simpler and cheaper method. There 

 are changes in the water such as to render 

 it unfit for boating, swimming and other 

 recreational purposes. These effects are read- 

 ily appreciated by the public, who should be 



anxious to support action where a public 

 attraction becomes an open offense to public 

 decency because some private interest wishes 

 to monopolize a great asset for the smallest 

 use. An enterprise which does not compen- 

 sate the state for its injured interests is a 

 deficit, and it should be the duty of con- 

 servation to prevent a selfish theft. 



EFFECT ON FISH LIFE 



The Conservation Commission already has 

 been intrusted with the enforcement of laws 

 to prevent the introduction of deleterious sub- 

 stances in quantities injurious to fish life. 

 Such effect is evident where acids or poisonous 

 wastes kill adult fish, or foreign substance 

 may render shellfish unattractive to the con- 

 suming market. If the oxygen dissolved in 

 the water becomes greatly diminished the fish 

 will suffocate. Water is to fish what the 

 ground and air combined are to land animals; 

 it furnishes the oxygen for respiration as well 

 as the food they eat. Organic wastes have 

 the power to absorb the oxygen from the water 

 and make it uninhabitable for fish life. Such 

 an oxygen demand can be readily determined 

 and its effect on the stream studied and pre- 

 dicted. Similarly those wastes which hurt the 

 production of fish food indirectly eliminate 

 fish from the water and its absence can not 

 be attributed to overfishing; and anything 

 which drives away the fish has the same effect 

 as removing them in other ways. 



Less evident, but equally important is the 

 effect upon the development of the young, the 

 ruin of hatching areas, and the death of the 

 fry which may bring the efforts of the hatch- 

 eries to naught. Even though the areas of 

 excessive pollution are localized to greater or 

 less extent they may form pollution dams 

 which interrupt the normal habits necessary 

 to fish propogation. It may be possible to 

 define the quality requirements of different 

 areas in such a way that by artificial assist- 

 ance each may be used for what it is par- 

 ticularly adapted, to the ultimate improve- 

 ment of the whole, at the same time giving 

 greater latitude for use of the industries. 



