Algal Blooms: A public health perspective
Muskoka Stewardship Conference May 2017 Karen Kivilahti Program Coordinator, Safe Water
Overview • • • •
Health effects and exposure pathways Precautions Public health role Challenges
Blue-Green Algae (BGA) • • •
30%-50% of blooms produce cyanotoxins Assume toxins are present Do not use water for infant formula
BGA Toxins
Cyanobacteria (BGA) Cell rupture Cyanotoxins
Hepatotoxins (e.g. Microcystins) Most Common
Neurotoxins (e.g. Anatoxins)
Dermatoxins (e.g. Aplsiatoxins)
Routes of Exposure Inhalation
Direct body contact
Ingestion
Potential Health Effects Human health risks depend on the type and concentration of the toxin as well as the route and duration of exposure. Cyanotoxin Hepatotoxins
Symptoms Vomiting, diarrhea, fever, abdominal cramps and potential liver damage
Neurotoxins
Muscle weakness, paralysis and breathing problems
Dermatoxins
Itchy, irritated skin and eyes
Exposure Pathways at the House/Cottage
Ingestion Ingestion
Ingestion/Inhalation/Skin
Inhalation Skin
Exposure Pathways at the Lake
Ingestion/Inhalation Ingestion/Inhalation/Skin
Ingestion/Inhalation/Skin Ingestion/Skin
Inhalation/Skin
Precautions to Take • Avoid using the water for drinking, preparing infant formula, food/drink, brushing teeth, bathing/showering
• Do not swim where a bloom is visible • Do not allow pets to drink or swim • Avoid watering your lawn or gardens with surface water • Avoid eating fish caught from the lake
Surface Water & Drinking Water Systems Municipal Systems
Small and Private Systems
• Monitor based on observations
• Monitor based on observations • Residential treatment systems may
and testing
• Effective and complex treatment • Monitoring finished water quality • Low risk
not be reliable
• Boiling water can increase toxin concentrations
• Increased risk
Public Health • Issues drinking water and swimming advisories • Identifies potential risks associated with recreational use • Determines potential risks for small drinking water systems • Communicates health-related issues and public notices • Monitors laboratory test results • Rescinds and updates advisories and public notices
Phased Approach
• Surveillance • Visual assessment • Screening/testing conducted by MOECC • Ongoing until terminated
• Intervention • Public notification (e.g. swim advisory, social media, door-to-door)
• Termination • Based on both visual observations and laboratory testing
Surveillance 1.Visual assessment and rapid field test 2.Public notification, if required 3.Algal identification 4.Screen for total microcystin 5.Confirm microcystin-LR (+ other toxins) Abraxis for Recreational Water,
Visual Assessment
• Acting on visual signs is more protective than relying on testing alone
• Visual signs of a bloom may include: • Presence of a scum or mat (e.g. spilled paint) • Reduced water transparency; and/or • Water may appear green or bluish-green
Intervention Door-to-door notification
Risk Communication
• Critical during and after an event • Effective communication of precautions that limit exposure • Challenges: • How to best notify the public and affected residents • Is it a known problem or is it new to the lake • The number of rental versus permanent residents • Toxin levels and the location of the bloom may vary • Toxins have been detected even when bloom is not visible
Acknowledgements • Health Canada • Ministry of the Environment and Climate Change • Ministry of Health and Long-Term Care • World Health Organization • United States Environmental Protection Agency • Sudbury and District Health Unit • Halton Region • Connecticut Department of Public Health and Fuss O’Neill
Contact Information Karen Kivilahti Program Coordinator – Safe Water 705-721-7520 Karen.Kivilahti@smdhu.org