392 
BULLETIN OF BUREAU OF FISHERIES 
for the lower plants in the aquatic food chain, ammonia determinations give a signifi- 
cant index of the balance between stream purification through the consumption and 
elimination of ammonium compounds formed during the disintegration of organic 
detritus, and the amount of such organic wastes received by the stream. In natural 
unpolluted waters organic detritus consists primarily of the remains of the organisms, 
both plant and animal, dying in the stream and adjacent waters, together with such 
organic matter as may be brought into the stream by surface run-off water. In 
unpolluted water, therefore, the amount of ammonia and ammonium compounds 
(chiefly ammonium carbonate) is usually very small. 
The West Riding Rivers Board (1930) found the ammonia content of the River 
Wharfe, an unpolluted stream, to vary between 0.0 and 0.17 p. p. m.; Butcher, 
Pentelow, and Woodley (1927) state the ammonia content of the river Itchen, 
normally to be less than 0.1 p. p. m. with a maximum of 0.25 p. p. m.; Pearsall (1930) 
found the waters of various English lakes to carry less than 0.01 p. p. m.; Domogalla, 
Juday, and Peterson (1925) report the ammonia in Lake Mendota to vary between 
0.0073 and 0.76 p. p. m.; and unpolluted portions of Wisconsin River above Rhine- 
lander, Wis. (Wisconsin State Board of Health, 1927) averaged 0.096 p. p. m. am- 
monia. In field studies by the Columbia, Mo., unit similar ammonia values, all i 
below 0.9 p. p. m., were obtained from analyses of unpolluted flowing stream waters. 
Polluted streams, even if carrying only a very small load of organic wastes, 
present quite a different picture and, as Winslow and Phelps (1906) have pointed 
out, from one- third to one-half of the total nitrogen of sewage will be in the form of 
free ammonia, largely as ammonium carbonate; and sewage will carry from 15 to 
35 p. p. m. or more of total nitrogen. Wiebe (1931b) reported a maximum of 0.224 
p. p. m. ammonia in the Mississippi River at Fairport, Iowa. Ellis (1935b) found 
from 0.36 to 1.16 p. p. m. ammonia in the Mississippi River at Davenport, Iowa, during 
low waters in the month of July (1934) in portions of the river that were not badly 
polluted and which were at the time supporting bass, catfish, and other warm-water 
fishes; and from 0.24 to 3.80 p. p. m. of ammonia in the badly polluted waters of the 
Mississippi River during September 1935 between St. Louis, Mo., and Cairo, 111. 
In the highly polluted Blackstone River, the Massachusetts State Board of Health 
(1913) reported 11.7 p. p. m. of ammonia. Similarly the writer has found 5.68 p. p. m. 
of ammonia in the Cache la Poudre River in Colorado at a point where there was 
heavy pollution with beet sugar factory wastes. 
In table 2 a group of ammonia data typical of the field findings by the Columbia, 
Mo., unit are presented. These data include no determinations from the immediate 
vicinity of sewers or other outlets pouring organic wastes into the streams, and no 
determinations from restricted local portions of streams in which unusual organic 
pollution was found. These data show the general range of dissolved ammonia 
which may be expected in our flowing streams during the warm season, and under 
the usual conditions of municipal and industrial pollutions. 
The composite series includes the ammonia values from all these stations collec- 
tively at which good fish faunae as previously defined were taken, and the Mississippi 
and coastal series include all stations in these systems regardless of fish faunae. 
