LOCALIZATION, DEPURATION, BIOACCUMULATION AND IMPAIRMENT OF ION REGULATION ASSOCIATED WITH CATIONIC POLYMER EXPOSURE IN RAINBOW-TROUT (ONCORHYNCHUS-MYKISS)

1. Static exposure of rainbow trout, Oncorhynchus mykiss, to three com mercial C-14-labelled cationic polymers (EDP, epichlorhydrin-dimethyla mine; CYT, polyacrylamide ester; and STK, polyacrylamide amide) result ed in C-14 being concentrated only in gill tissue. 2. Depuration studi es examining the effect of humic acid (HA) cn cationic polymer bound i n gill tissue indicate that the binding is reversible with exposure to polymer-free water and polymer-free water with HA for each of the thr ee polymers. 3. Analysis of blood pH, Na+, K+, total NH3 and Cl- after static water exposures to EDP (m.w. 50 000) at 7.5 mg EDP/1 revealed a treatment related decrease in blood pH, from 7.1 to 6.6, accompanied by an increase in blood NH3 and evidence of severe impairment of ion regulation. 4. Repeated exposure to the cationic polymers did not resu lt in increases in the C-14 concentration in gill tissue suggesting th at bioaccumulation of the polymers does not occur. 5. These data sugge st that the gill is the site of toxicity for these cationic polymers a nd that their toxic effects involve gill function and ion regulation r ather than systemic actions on internal organs.