428 
BULLETIN OF BUREAU OF FISHERIES 
Potassium sulphate, K 2 S0 4 
Wells (1915b), 869 p. p. m. in tap water killed bluegills, Lepomis pallidus, in 4 days. 
Potassium xanthate or potassium ethyldithiocarbonate C 2 H 5 -OCS-SK 
Used in ore floatation processes and on occasion to free soil from insect pests, and it is highly 
toxic to fishes. M. M. E., 10 p. p. m. in hard water killed goldfish in 48-96 hours, 0.1 p. p. m. in 
4-5 days. 
Pyrethrum 
The volatile oil in this plant product is quite toxic to fishes. Bandt (1933) 5-10 p. p. m. toxic 
for carp. 
Pyridine, CsHjN 
In gas wastes, also in waters draining recently burned-over areas where combustion near ground 
has been incomplete. Shelford (1917), 1,477-1,576 p. p. m. in tap water killed orange-spotted 
sunfish, Lepomis humilis, in 1 hour; Powers (1917), 1,869 p. p. m. in distilled water killed goldfish 
in 10-30 hours; Demyanenko (1931) states 1,000 p. p. m. to have a feeble effect on fishes. 
Quinoline, C 6 H 4 N : CHCH : CH 
Gas wastes. Shelford (1917), 52-56 p. p. m. and 65 p. p. m. isoquinoline in tap water killed 
orange-spotted sunfish, Lepomis humilis, in 1 hour. 
Saponin, a glucoside 
Found in various plants. Ebeling (1928) points out that wastes from potato starch factories 
carry sufficient saponin to be dangerous to fishes, and that consequently these wastes should be 
highly diluted. M. M. E., 10 p. p. m. of saponin in hard water produced marked distress in gold- 
fish in 5 hours, 100 p. p. m. rapidly fatal, killing goldfish in 7-24 hours. 
Sodium arsenite, commercial preparation usually a mixture of several sodium and arsenic 
compounds 
Some dye and tanning processes; removal of aquatic vegetation. Since arsenic trioxide is 
usually dissolved in sodium hydroxide, and since each lot of commercial sodium arsenite must be 
assayed for its arsenic content, arsenic, arsenic trioxide, and sodium arsenite are considered under 
this single heading. Wiebe (1930), 7 p. p. m. of As 2 C >3 in Mississippi River water was not detri- 
mental to largemouth black bass, Micropterus salmoides, smallmouth black bass, Micropterus 
dolomieu, white crappie, Pomoxis sparoides, bluegill, Lepomis pallidus, golden shiner, Notemigonus 
crysoleucas, bullhead, Amieurus nebulosus, and goldfish, Carassius auratus, in 148-hour exposures 
as shown by 3 months subsequent observation. Surber and Meehan (1931), 2 p. p. m. As 2 C >3 in 
Mississippi River water survived by the important fish food organisms, but 2.5-4 p. p. m. killed 
chironomid larvae, mayfly nymphs, the fresh- water shrimp, Hyalella, and odonata nymphs; the 
isopod Asellus sp., survived 10-21 p. p. m.; M. M. E., 1.3 p. p. m. As 2 0 3 in distilled water killed 
Daphna magna, 8 p. p. m. hard water had no appreciable effect on the fresh-water mussel, Amblema 
peruviana, but 16 p. p. m. in hard water was fatal to Amblema peruviana in 3-16 days. 
Sodium carbonate, Na 2 C0 3 
Found in many chemical effluents. Clark and Adams (1913), 250-300 p. p. m. killed shiners, 
carp, and large suckers in tap water in a few hours; Wells (1915b), 530 p. p. m. in tap water killed 
bluegills, Lepomis pallidus, in 3 days. 
Sodium chlorate, NaClCb 
In some effluents from chlorine and bromine works. Not markedly toxic. M. M. E., 1,000 
p. p. m. in hard water produced no apparent injuries in goldfish during exposures of 5 days duration. 
