530 
BULLETIN OF THE BUREAU OF FISHERIES 
from fresh water to even dilute salt solutions show the potential dangers to the 
fresh-water mussels from the addition of salt to the water in which they are living, 
which may result from the introduction of certain types of industrial wastes. 
The pH values of the blood of mussels from the sodium chloride series seemed 
to vary toward neutrality, the greater the concentration of the salt solution. This 
finding, in view of observations made in other series, suggests that the stronger 
solutions, as might be expected, were producing more extended disturbances of the 
body functions than the weaker solutions. 
POTASSIUM SALTS 
Various species of mussels were tested in solutions of potassium chloride, potassium 
HOURS 
Figure 11. — Specific gravity of the blood of fresh-water mussels 
in tap water plus potassium salts. All animals with valves 
propped open. Black circle, 1 per cent potassium chloride; 
circle, 0.50 per cent potassium chloride; black triangle, 0.25 per 
cent potassium chloride; triangle, 0.10 per cent potassium chlo- 
ride; square, 0.5 per cent carbonate; black square 0.25 per cent 
potassium carbonate; and black triangle, 0.25 per cent potassium 
sulphate 
carbonate, potassium sulphate, and in a mixture of potassium chloride and calcium 
chloride. These series are summarized in Table 14 and Figure 11. 
The toxic action of the potassium salts on fresh-water mussels is evident from these 
tests, and is in accord with the known toxic action of potassium compounds to other 
types of animals. The mussels rapidly became moribund in solutions of potassium 
salts, and as a result the potassium series were not carried beyond 24 hours in most 
cases. 
The general effects of potassium salts on the specific gravity of the blood were 
the same as those noted for the sodium chloride series. The animals made rapid 
adjustments in the specific gravity of the blood, the actual values being well above 
the average normal specific gravity of fresh-water mussel blood. 
Owing to the high toxicity of the potassium salts, the body condition declined 
rapidly and the alkalinity of the blood was lowered, as in other moribund mussels. 
Extreme retraction of the foot was evident in mussels dying in solutions of potassium 
salts. 
