ACUTE TOXICITY OF WASTE-WATER TREATMENT POLYMERS TO DAPHNIA-PULEX AND THE FATHEAD MINNOW (PIMEPHALES-PROMELAS) AND THE EFFECTS OF HUMIC-ACID ON POLYMER TOXICITY

This study assesses the acute toxicity of 34 wastewater treatment polymers and additives to the water flea Daphnia pulex and the fathead minnow (Pimephales promelas). D. pulex were more sensitive than the fathead minnow to 81% of the polymers tested. A reversal in species sensitivity was observed for some polymers. Results of this study indicated that polymer chemistry is generally the factor controlling polymer toxicity to D. pulex, while charge density is generally the factor controlling polymer toxicity to the fathead minnow. Molecular weight of the polymers could not be correlated with toxicity to either species. Addition of humic acid to the test waters reduced polymer toxicity to both species by over two orders of magnitude, indicating that toxicity studies with polymers in standard laboratory waters will likely overestimate the toxicity of polymers under actual use conditions.