414 
BULLETIN OF BUREAU OF FISHERIES 
It may be noted in this table that the addition of progressively larger quantities 
of sodium nitrate to the copper sulphate solution increased the survival time of fishes 
from 2 hours 30 minutes to 6 hours 40 minutes, up to a concentration of 1 : 200 for 
sodium nitrate. Beyond that concentration the osmotic action of the sodium nitrate 
became unfavorable (see osmotic pressure, p. 408) and the survival time deci eased 
with a further increase of sodium nitrate, i. e., sodium nitrate, which does not precipi- 
tate copper, both increased and decreased the survival time of fishes exposed to the 
lethal action of same amounts of copper sulphate according to the concentration of 
sodium nitrate present. The second half of this table shows the marked increase in 
survival time from 2 hours and 30 minutes in the copper sulphate alone to 12 hours 
45 minutes in the same strength of copper sulphate solution to which both sodium 
nitrate and calcium chloride were added. The amount of calcium chloride used was 
very small, namely, 50 p. p. m., and in this concentration no precipitate formed, yet 
this quantity of calcium chloride greatly enhanced the protective action of the sodium 
nitrate against the lethal action of copper sulphate. 
These discussions of the precipitation of metallic compounds out of effluents 
and of the synergistic and antagonistic actions of compounds which do not preci- 
pitate the particular metal in question show, both specifically in the case of effluents 
carrying compounds of metals and in general in the case of all stream pollutants 
carrying chemical wastes, that field examinations of local conditions, analyses both 
of the effluents and the water receiving these effluents, and bioassays of the mixtures 
of the two must be made before the lethal limits of such wastes can be determined. 
In table 1 1 summarized data from a large series of tests covering the lethality limits 
of certain compounds of eight metals found in commercial effluents are presented. 
From these data the expected lethal ranges and the relative lethality of these eight 
compounds in various types of water, together with the changes in salt balance and 
relative acidity produced by these compounds, may be estimated if uncomplicated 
by substances other than those normally found in stream water, or by excessive 
amounts of those substances. 
Table 11. — Survivals of 850 goldfish in various concentrations of salts of 8 metals found in industrial 
wastes 1 
Substance 
Concen- 
tration 
ratio by 
Parts 
per 
mil- 
Diluent 
water 
pH 
Specific eon- 
ductivity 
inhoXlO -6 
at 25° C. 
Survival time 2 
Constituent of— 
weight 
lion 
Water 
Solu- 
tion 
Water 
Solu- 
tion 
Aluminum potassium 
sulphate. 
3 1:1,000 
1,000 
Hard 
7.8 
5. 5 
678 
1,247 
1 to 10 hours 
Do. 
3 1: 10,000 
100 
do - 
7.8 
6.8 
678 
736 
12 hours to co . 
•Tannery wastes. 
Do 
3 1:100, 000 
10 
_ do__ 
7.8 
7.6 
678 
584 
Do. 
1:1,000, 000 
1 
___do_ 
7.8 
7. 7 
678 
677 
OO 
Cobaltous chloride 
1:1,000 
1,000 
Very soft 
6.2 
6.6 
<50 
1,906 
28 to 29 hours 
Electroplating 
wastes. 
Do- 
1:1, 000 
1,000 
Hard. 
7.8 
7.2 
647 
2,265 
30 to 31 hours _ 
Do. 
1:10, 000 
3 1:1, 000 
100 
Very soft 
6. 2 
6.5 
<50 
<50 
690 
308 
168 hours to <» . __ 
1, 000 
1,000 
Glass distilled. _ 
7.0 
5.6 
1, 123 
1,348 
1 to 2 hours 
~Do r_ 
3 1:1,000 
Hard 
7.8 
6.8 
1 hour to 2 hours 20 
no 
3 1:10, 000 
100 
_ do 
7.8 
7.0 
671 
637 
minutes. 
3 hours to 11 hours _ 
Copper and 
i brass indus- 
tries wastes. 
Do. 
1:10, 000 
3 1:100,000 
100 
do 
7.9 
7.0 
635 
637 
3 to 41 hours 
Do_ 
10 
_ -__do 
7.9 
7.6 
635 
671 
11 to 72 hours 
Do_ 
1:100,000 
3 1:1, 000, 000 
10 
__ do 
7.9 
7.7 
635 
700 
48 hours to _ 
Do 
1 
do 
7.9 
7.5 
635 
640 
72 hours to <= 
