PLANKTON IN WATER SUPPLY MEIER 401 



taste is observed immediately. The distasteful oil of Synura per- 

 sists in a water supply for some time, so if Synura makes its presence 

 known in the water supply in any small amounts, it should be im- 

 mediately checked. 



OTHER ALGAL NUISANCES 



Masses of organisms in the water supply cause turbidity, and 

 even a small amount of them may result in the formation of stain 

 and scum on white porcelain basins and bathtubs. The tiny, slen- 

 der plant, Aphunizomenon, which floats in the water even when 

 dead, is able to accumulate in hot-water systems to such an extent 

 as to appear in the surface water of a full bathtub. 



In industry, the presence of algae in the water may cause trouble. 

 They have been known to interfere with proper cleaning of clothes 

 in laundries. Algae have prevented the formation of correct colors 

 by dye manufacturers and have hindered the proper dyeing of goods. 

 Bad results in the process of developing in photography have also 

 been traced to the presence of algae in the water. 



Because of the Avarm temperature of the water and the optimum 

 lighting conditions, swimming pools are favorite places for algae 

 to grow. The organisms become seeded on and between the tiles, 

 which should be scrubbed with an algicide when the pool is emptied 

 and cleaned. 



Swimmer's itch, in one instance, was found to have been caused 

 by Cercariu elvas^ a parasite belonging to the group Schistosoma. 

 It was found that snails carried these parasites, but the use of an 

 algicide, such as copper sulfate, in doses of 0.5 to 2.0 parts per million 

 destroyed the snails within 48 hours. 



RED WATER 



Often when complaints about the water are made to the water 

 engineer, the cause of the difficulty is found to lie in a defective pipe 

 line that delivers the water to the consumer. Due to the electrolytic 

 action, iron from the pipe may go into solution. Some of the oxygen 

 in the water then helps to change the soluble ferrous hydroxide to 

 insoluble ferric hydroxide which precipitates in the pipe. If the 

 water is very soft, the high content of the carbon dioxide increases 

 the rate of corrosion. If the water is not treated, a deposit of organic 

 matter may be found in the pipe line. The relatively high tempera- 

 ture increases this deposit during the summer, thus causing a further 

 decrease in the amount of dissolved oxygen and an increase in the 

 amount of carbon dioxide. The increased carbon dioxide further 

 accelerates corrosion and the acid environment favors the growth of 

 iron bacteria. The corroding action of the acid water produces a 



