Huff: RESPONSE OF MICRO-ORGANISMS TO COPPER SULPHATE 411 



copper sulphate attached to either side was used for distributing 

 in the central part of the lake. 



The following chemical analyses were made by Mr. V. H. 

 Roehrich, Director of the Bureau of Municipal Testing Laborato- 

 ries, Department of Public Utilities, of the City of St. Paul : 



SAMPLE OF WATER TAKEN AT VADNAIS LAKE, AUGUST 13, 1915 



Sanitary Analysis Boiler Analysis 



Parts per Parts per 



million 100,000 



Suspended matter 3.000 Total solids (dissolved) 16.50 



Total solids (dissolved) 165.000 Total hardness 13.30 



Chlorine 6.000 Sulphate hardness 20 



Nitrogen as free NH3 086 Total alkalinity 13.50 



Nitrogen as albuminoid NH. .494 Alkali salts 3.00 



Nitrogen as nitrites 001 Sodium carbonate 00 



Nitrogen as nitrates 480 Foaming rate Very good 



Oxj'gen consuming power 2.700 Incrusting rate Very good 



The following figures from Mr. Roehrich's report on the deter- 

 mination of copper in water taken from the terminal chamber at 

 McCarron Pumping Station, four miles below Vadnais Lake, show 

 how quickly the copper disappears from the water after a copper 

 sulphate treatment : 



About .03 parts of copper per million was introduced into Vad- 

 nais Lake at 11 :00 a.m. on June 14. 1915. 



Parts of 



copper 



per million 



Sample No. 1. Taken June 14, 1915 at 5 : 30 p.m 0005 



Sample No. 2. Taken June 15, 1915 at 2 :30 p.m 0175 



Sample No. 3. Taken June 16, 1915 at 5 : 30 p.m 0015 



As has been stated by Moore and others, it is impossible to 

 give definite figures for the amount of copper sulphate necessary 

 to eradicate a given organism, for several factors must be consid- 

 ered. The temperature of the water, the amount of organic mat- 

 ter present, as well as the presence or absence of various chemical 

 substances such as calcium, magnesium, oxygen, and carbon diox- 

 ide, etc., probably have their effect upon the amount of copper 

 sulphate necessary to destroy a given organism, and just what part 

 each of these factors plays in the action of the copper sulphate 

 upon algae, has not yet been determined. The figures, therefore, 

 representing the quantity of copper sulphate necessary to eradi- 



