This study documents the acute toxicity effects of varying concentrations
of zinc on certain fishes native to Illinois. Fourteen-day bioassays were performed
with bluegill fry, channel catfish fingerlings, and largemouth bass
fingerlings in waters relatively high in alkalinity and the salts of calcium and
magnesium.
The 14-day median tolerance limit at 20 C was 11.0 mg/l soluble zinc for
the bluegill, 8.2 mg/l soluble zinc for the channel catfish, and 8.0 mg/l soluble
zinc for the largemouth bass. For protection of the fishes investigated, and in
compliance with Illinois water pollution regulations, soluble zinc concentrations
in Illinois streams having high alkalinity and hardness should not exceed
0.8 mg/1.