Alkalinity 



The property of buffering in a lake may be important to prevent 

 sudden shifts to extreme acid or alkaline condition. Therefore, 

 acidity and total alkalinity were determined because of their capacity 

 to neutralise m»ny types of wastes. The method used for determining 

 these alkalinities involved the use of two indicators; phenolphtha- 

 lein and methyl orange. Titration was done with .02 normal sulfuric 

 acid. Since the alkalinity is generally the result of carbonates, 

 oalciton carbonate in particular, three types of alkalinity were 

 evaluated (Table 3) ~ namely, hydroxide (OH), normal carbonate (CO ), 

 and bicarbonate (HCO ) -- the three summed as total alkalinity ex- 

 pressed as calcium carbonate* 



With the range of carbonates and bicarbonates as calcium car- 

 bonate extending between 35 and 62 P.P.M., Roosevelt Lake lies well 

 within the bounds (0 to 350 P.P.M.) established for natural tinpolluted 

 waters supporting good fish fatuia. The expected values for most lakes 

 are between 45 ajid 200 P.P.M. No evidence of hydroxides, which are 

 added through pollutants or chemical wastes and may cause great damage 

 to the faima, was found in any of the samples taken. 



Carbon Dioxide and Acidity 



Free Carbon dioxide and total acidity as oalcixxm carbonate were 

 determined by titration with h/44 sodium hydroxide solution using 

 phenolphthalein as the indicator. As in the majority of natural 

 waters containing good fish fauna, Roosevelt Lake has very little 

 free carbon dioxide (Table 4). The scarcity of free carbon dioxide 

 is due to its reaction with other compounds in solution plus con- 

 stant aeration. Small quantities are important, however, to bacterial 

 growth and photosynthetio activities of chlorophyll bearing plants. 



The importance of acidity in the .water lies in its capaoitj' to 

 neutralize alkaline pollutants and other types of wastes. Its presence 

 in natural waters is usually due to the presence of carbon dioxide and 

 other organic acids. Carbonates and bicarbonates in the quantities 

 found have little immediate effect on fish, but do influence the 

 living habits of the fish indirectly. Bicarbonates are necessary 

 for the process of photosynthesis which completes the food chain 

 upon which fish depend. Even though in some samples only small traces 

 of carbonate were found, and the amounts in others were undetectable, 

 these minute quantities are valuable for phytoplankton and other aquatic 

 plants • 



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