Acute and long‐term toxicity of water‐soluble cationic polymers to rainbow trout (Oncorhynchus mykiss) and the modification of toxicity by humic acid

Abstract

The toxicity of two classes of cationic polymers, epichlorhydrin/dimethylamine polyamines and quaternary amine copolymers, were investigated. Static bioassays of those polymers resulted in LC50 concentrations ranging from 271 μg/L to 1,733 μg/L. Under flow‐through conditions the toxicity was 1.7 to 13.9 times greater, depending on the polymer used. Using a reference humic acid along with the polymers in toxicity studies, strong correlations were established between humic acid concentration and LC50. Even at a fairly low humic acid concentration (5 mg/L), the toxicity of the polymers was reduced 7‐ to 16‐fold. At higher humic acid concentrations (50 mg/L), cationic polymer toxicity was reduced 33‐ to 75‐fold. Copyright © 1991 SETAC