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Blue Green algae: an overview

Blue Green algae: an overview

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Blue Green algae: an overview

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  1. Blue Green algae: an overview Monique D’Amour Safe Environments Programme (Longueuil, Québec) and Michèle Giddings Water Quality & Microbiology Division (Ottawa, Ontario) Health Canada

  2. Federal (Health Canada) advice research risk assessment/management with provinces drinking water quality on Federal lands Provincial/Territorial provision of safe DW source water protection water treatment monitoring & surveys research Federal-Provincial Roles and Responsibilities for Drinking Water Responsibilities divided among levels of government

  3. Representatives from each province, territory, and the federal government 30+ year working collaboration Meets twice yearly Establishes the Guidelines for Canadian Drinking Water Quality Health Canada’s Water Quality and Health Bureau is the Technical Secretariat to the Committee Federal-Provincial-Territorial Committee on Drinking Water

  4. Drinking Water Guideline Development Process Identification Assessment Evaluation • costs • benefits • consultation

  5. Cyanobactieria in Canada • Identification of a problem • Assessment was required

  6. Cyanobacterial Toxins in Canada: The History, Part I • 1990-1992-1993: M-LR identified in Alberta lakes, detected in Shoal Lake, Winnipeg’s drinking water source, and in the city’s distribution system • Manitoba requests an ‘Emergency Health Advisory’ (EHA) from Health Canada in 1994 • EHA of 0.5 µg/L derived for M-LR in DW • EHAs are developed for specific situations; they do not have the rigorous review/consultation of full guidelines

  7. Cyanobacterial Toxins in Canada: The History, Part II • M-LR added to the priority list for evaluation • Canadian surveys to date indicate Microcystin-LR is the most common hepatotoxin present in water supplies

  8. Blooms of Cyanobacteria in Canada • Blooms occur in all provinces (Prairies, Québec etc) Tend to occur repeatedly in same supply • small shallow, slow-moving bodies of water common to prairies generally affected

  9. Bloom

  10. Cyanobacteria: General Description • Cyanobacteria (blue-green algea) • May produce neurotoxins, hepatotoxins • Skin irritants, other toxins • Surface water supplies (Hepatotoxins/neurotoxins) • Hepatotoxins more widespread

  11. Microcystin -LR Microcystin L-R: hepatotoxins Produced by Microcystis aeruginosa (an others blue-greens algal species) Monocyclic heptapeptides (L–amino acids; L=Leucine; R=arginine)

  12. Microcystin-LR Structure

  13. Sources of Human Exposure • Consumption of drinking water • Recreational use of lakes and rivers • oral, dermal • Showers • inhalation, dermal • Algal food tablets • oral

  14. M-LR Effects on Animals & Humans • Humans • Stomach cramps, vomiting, diarrhea, fever, headache, painful muscles & joints • Acute gastroenteritis • Liver damage • Animals • Primarily hepatotoxin • Kidney damage • Lung damage • Tumour promotor

  15. Critical Effects • Microcystin administered by gavage to mice at levels of 0, 40, 200 and 1000 µg/kg bw/day for 13 weeks 40 µg/kg bw : no definite effect 200 µg/kg bw : slight liver changes in some animals 1000 µg/kg bw : liver changes in all animals • No-Observed-Adverse-Effect Level (NOAEL) set at 40 µg/kg bw/day

  16. 0.040 mg/kg bw/day 1000 TDI = = 0.00004 mg/kg bw 0.00004 mg/kg/day x 70 kg x 0.80 1.5 L/day MAC = = 0.0015 mg/L (1.5 µg/L) M-LR Guideline Derivation Where • x10 for intraspecies variation • x10 for interspecies variation • x10 for less than lifetime study

  17. Factors Affecting Bloom Formation & Toxin Production / Persistence • Bloom Formation • Inorganic nutrients • Water temperature • pH level: 6-9 • Daylight • Turbidity • Turbulence • Water flow • Toxin production • Environmental factors • Temperature, light, nitrogen levels, carbon dioxide and/or pH • Genetic differences • Metabolic processes • Toxin release • Persistence • Stable in water • Resistance to pH extremes • Heat resistant

  18. Microcystins – Water Management • Reservoir management • Nutrient deprivation practices • Algal cell removal • Coagulation, clarification, filtration, disinfection • Must not damage cells • Toxin removal • Oxidation (ozonation); other methods such as UV, chloramination & hydrogen peroxide not as effective • Activated carbon (wood-based products best) • Slow sand filtration-biodegradation

  19. Flow chart: Management Water supply

  20. Find more information To obtain the supporting document on M-LR http://www.hc-sc.gc.ca/hecs-sesc/water/ pdf/microcys.pdf To obtain information onDW http://www.hc-sc.gc.ca/hecs-sesc/water/index.htm

  21. Acknowledgements Michèle Giddings for providing technical supports, advices and specific expertise on Microcystine L-R and Drinking Water Guidelines