PH15 Filling Critical Data Gaps in Ecological Risk Assessment
Exhibit Hall
8:00 AM - Thursday
(PH181) Environmental Effects of the Aquaculture Therapeutant Potassium Permanganate.
Hobbs, M1, 2, Grippo, R2, Farris, J2, Griffin, B1, Harding, L2, 1 HKD SNARC/ARS/USDA, Stuttgart, AR, USA2 Environmental Sciences Ph.D. Program, Arkansas State Univ., State University, AR, USA
ABSTRACT- Potassium permanganate (KMn04) is an aquaculture drug used for treating and preventing parasitic and fungal diseases. Our research goal is to generate effects data suitable for developing an ecological risk assessment of KMn04. The following tiered approach is being followed: 1) determine acute sediment and water toxicity of KMn04 in laboratory conditions: 2) determine chronic toxicity in laboratory conditions; 3) evaluate fate and toxicity in pond water under recommended dose and worst-case overdose scenarios: 4) determine fate and toxicity in simulated warm-water pond (mesocosm) conditions. Previous laboratory-based toxicity tests, utilizing synthetic laboratory water, aquaculture pond water and sediment, indicated that pond substrates provide an ameliorating effect on KMn04 toxicity, reducing 96 hr LC50 toxicity (mg/L) from 0.061 to 2.41 (Daphnids); 1.95 to 11.28 (Pimephales promelas); and 4.4 to 12.54 (Hyalella azteca and Chironomus tentans) in synthetic and pond waters, respectively. Ten day sediment tests on Hyalella azteca and Lumbriculus varietgatus indicated that spiked pond sediments were toxic only at g/kg levels of KMn04, with LC50s of 10.1 and 13.8, respectively. In the present study channel catfish were stocked in outdoor mesocosms designed to simulate aquaculture ponds. Exposure concentrations of 1, 3, and 5 times the recommended therapeutic dose were administered over 12 months simulating normal dose and overdose treatments. Standard whole effluent and sediment toxicity tests were then performed. No toxicity was observed in either the effluent or sediment for all treatment levels. The 3X and 5X overdose treatments caused 100% mortality of the stocked fish within six hours post treatment while showing no toxic effect on standard test organisms two weeks post treatment, suggesting reduced toxicity of potassium permanganate after exposure in the environment. Results from the mesocosm phase provide a more ecologically relevant and holistic understanding of the effects KMn04 has on complex systems compared to laboratory studies.
Key words: toxicity, Potassium permanganate, ERA, Aquaculture