FUTILITY OF A SANITARY WATER ANALYSIS 



47 



by reason of the amounts of nitrites. The water, however, is abso- 

 lutely unpolluted. The first sample contained two bacteria, and the 

 second, one bacterium per c.c. Only one species was represented, 

 which was not B. coli. 



SERIES "T." 

 PARTS PER MILLION. 



For a final example the following analysis is submitted, the expres- 

 sion of results being in terms of parts per million: 



Free ammonia 0.012 



Albuminoid ammonia 0.012 



Nitrites o.oo 



Nitrates "strong" 



The above water is from a well in Rochester, Minn. It will 

 be seen that the ammonias are extremely low in amount, and the 

 nitrites and nitrates practically absent. It is a water which con- 

 forms in all respects to the standards above quoted, yet it contained 

 1,570 bacteria per c.c., and an abundance of B. coli. 



There remain for consideration the artesian or deep-seated rock 

 waters. Examples might be cited in the support of the general 

 contention of this paper, but it will be distinctly preferable merely 

 to refer to a paragraph in the address above quoted, as follows: 



Unfortunately, however, in the study of artesian water perplexing chemical 

 and bacteriological results are often obtained. In artesian waters so situated that 

 surface pollution seems impossible, amounts of nitrogen as free ammonia, as nitrites, 

 and as nitrates have often been found which, if occurring in ground waters, would 

 cause them to be considered as polluted. The nitrogen of the nitrates in these waters 

 may be due to fossil remains, and the nitrogen as nitrites and as free ammonia to the 

 reduction of the nitrates by chemical action, as contact with iron sulphide, and the 

 occurrence of the nitrogen as free ammonia also sometimes to some salt of ammonia 

 existing in the strata through which the ground water passes. On this account the 

 determination of the nitrogen content does not give as satisfactory data from which 

 to draw conclusions as those obtained from the analysis of ground water. 



