More Related Content
Similar to Control of Potentially Toxic Cyanobacteria Using Chemicals 2017
Similar to Control of Potentially Toxic Cyanobacteria Using Chemicals 2017 (20)
Control of Potentially Toxic Cyanobacteria Using Chemicals 2017
- 1. Control of Potentially Toxic Cyanobacteria Using Chemicals or Fish Gary J. Burtle University of Georgia Animal & Dairy Science - Tifton
- 2. Unusual Number of Toxic Blooms • Toxic Algae blooms in Georgia causing cattle deaths • Blame placed on drought conditions • Rains in early 2012 followed by drought lead to concentration of nutrients in pond water • Reduced pond flushing
- 3. Cattle Deaths • More than two dozen ponds with reported cattle problems – Six cases of cattle deaths • 2 to 8 cattle deaths per case • Aborted or still birth calves in surviving cows – Others with avoidance of pond water or dense algal blooms
- 4. Main Algae Suspects Microcystis Cylindrospermopsis Euglena sanguinea Euglena
- 5. Some Algae Toxins Algae Toxins Microcystis Anabaena Planktothrix (Oscillatoria) Aphanozomenon Nostoc Microcystins (liver) Anatoxin-a (nerve) Cylindrospermopsis raciborski Cylindrospermopsin (liver, kidney) Saxitoxin (nerve) Euglena sanguinea Euglenophycin* (neurological) Lyngbya Lyngbyatoxin-a (skin) Aplysiatoxins (skin, gastro-intestinal) Toxic Cyanobacteria in Water: A guide to their public health consequences, monitoring and management. Edited by Ingrid Chorus and Jamie Bartram, World Health Organization, 1999. *Identification of euglenophycin--a toxin found in certain euglenoids. Zimba PV, Moeller PD, Beauchesne K, Lane HE, Triemer RE. Toxicon. 55(1):100-4. 2010.
- 6. Fate of toxins in the Environment “It appears likely that cyanotoxins are produced and contained within the actively growing cyanobacterial cells. Release to the surrounding water, to form dissolved toxin, appears to occur mostly, if not exclusively, during cell senescence, death and lysis, rather than by continuous excretion. “ Kaarina Sivonen and Gary Jones, WHO 1999.
- 7. Tifton Studies on Algae Control • Planktivorous fish – Threadfin shad (600 per acre) – (Or, stock 100/A and encourage spawning) • Algicides – Copper sulfate plus sodium percarbonate – Cutrine plus
- 8. How to Improve Results of Sodium Percarbonate Application • Increase rate of application…from 8 lb to 25 lb/A • OR, use in combination with COPPER – 0.1 to 0.25 ppm as copper sulfate • Apply early in the day, before full sun or late in the day, after full sun
- 9. Treatment Evaluated • 0.25 ppm Copper Sulfate crystals (0.675 lb per acre ft of pond water) – Dissolve in warm water before distribution • 25 lb GreenClean per acre ft of water – Broadcast over the pond area as evenly as possible • Applied before 10:00 AM
- 10. Changes to Phytoplankton after Treatment 0.25 ppm Copper Sulfate plus 25 lb/Acre Sodium Percarbonate Time Microcystis Aphanocapsa Rhabdoderma Scenedesmus Initial 1,544 33,977 6,037 1,895 24 hr. Post Treat 210 22,324 1,334 2,257 48 hr. Post Treat 929 14,531 772 7,582 72 hr. Post Treat 421 12,987 351 7,722 Pond 18 – Moderate Bloom Colony units per milliliter, average of 4 samples.
- 11. Changes to Phytoplankton after Treatment 0.25 ppm Copper Sulfate plus 25 lb/Acre Sodium Percarbonate Time Microcystis Aphanizomeno n Rhabdoderma Scenedesmus Initial 53,212 2,808 842 9,547 24 hr. Post Treat 54,194 1,544 ND 6,318 48 hr. Post Treat 35,942 421 982 9,126 72 hr. Post Treat 45,541 421 421 9,574 Pond 22 – Dense Bloom Colony units per milliliter, average of 4 samples.
- 12. General Observations • Algicide treatment can be selective • Apply before dense scums appear • Reapplication will probably be necessary, but perhaps only with Sodium Percarbonate • Cost of chemical per acre ft: about $51.00
- 13. Implications • Begin control before dense blooms develop. • Pond owner should adopt long range plan for phytoplankton management – including drought conditions. • Repeat application – 1 to 2 weeks apart • Test for toxin – County Office – About $100