220 ANALYSIS OF WATER 



Free Ammonia. 



1st cylinder matched by 2 c.c. 



standard . . . . = 0-02 mg. NH3 

 2nd cylinder matched by 0-5 c.c. 



standard . . . . = 0-005 »> 

 3rd cylinder matched by 0-2 c.c. 



standard . . . . = 0-002 „ 



4th cylinder matched by nil . — 



0-027 mg. NH3 

 A Ibuminoid A mmonia. 



1st cylinder matched by 4 c.c. 



standard . . . .=o-04mg. NH3 



2nd cylinder matched by 2 c.c. 



standard . . . . = 0-02 „ 



3rd cylinder matched by 0-5 c.c. 



standard . . . . = 0-0005 „ 



4th cylinder matched by nil . — 



0-065 nig- NH3 



Thus in i litre there would be 0-054 mg. free ammonia 

 and 0*130 mg. albuminoid ammonia. As milligrams 

 per litre are parts per million, the water would be 

 stated to contain 0-054 parts per million of free ammonia 

 and 0-130 parts per million of albuminoid ammonia. 



213. Interpretation of Results from the Ammonia 

 Estimations. 



The determination of ammonia is important, as both free and 

 albuminoid ammonia nearly always indicate the presence of animal 

 organic matter, generally sewage contamination. Free ammonia 

 is readily oxidised to nitrites and nitrates, and hence its presence,- 

 in considerable quantity, usually indicates recent pollution and 

 absence of oxidation. 



The albuminoid ammonia is a measure of the nitrogenous 

 organic matter present, since all proteins and many other nitro- 



