Cyanobacteria and Human Health in the Mississquoi Bay Lake Champlain, Vermont

1. Cyanobacteria and Human Health in the Mississquoi BayLake Champlain, Vermont

2. Problem/Issue • There is a lack of understanding on the potential risks to human health posed by different levels blue-green algae contamination within the Mississquoi Bay. • There has yet to be an effective public alert system that protects human health while minimizing negative impacts on Vermont’s tourism industry. • Andrew Notte, Jennifer Sinish, Kristen Rigney, and Adam Trescott

3. Goal/Purpose Statement • To assess the level risk to human health posed by cyanobacteria contamination in the Mississquoi Bay while considering associated economic factors and public policy. • Determine the most significant impacts on human health.

4. Cyanobacteria • Occur naturally in lakes and rivers • Commonly referred to as Blue-Green Algae • Species can range in color from olive-green to red • Photoautotrophs • Use CO2 as carbon source • Can convert sunlight into energy

5. Human Activities that Encourage Bloom Growth • Urban and agricultural runoff • Reduction in water flow as a result of increase water usage • Degradation through land clearing and other urban and agricultural activities

6. Toxic Blooms Certain species of cyanobacteria release toxins when they decompose called cyanotoxins.

7. Cyanobacteria are able to control their buoyancy by adjusting their gas vacuoles This allows them to travel to the warmer photic zone at the surface The lack of mixing leaves the cyanobacteria virtually undisturbed at the surface where it receives full light and can flourish Thermal Stratification

8. Cyanobacteria in Lake Champlain • In 1999 cyanobacteria were first documented in Lake Champlain • Each year there are one to two dog deaths attributed to cyanobacteria • There have been no human deaths

9. Summer Tourism in Vermont • In 2001, tourism was estimated to have a $4.24 billion impact on Vermont’s economy • Summer 2001 was $1.23 billion • Out of the total summer visitors in Vermont • 22% participated in outdoor recreation • Of that percentage, 27.5% participated in water recreation

10. Chronic Exposure • Outdoor recreation participants are more likely to visit multiple times a year • They spend an average of 8 nights per visit Since outdoor enthusiasts visit longer and more often, their likelihood of suffering from chronic exposure is increased

11. Alert System and Tourism Human health is more important than the impact beach closures and swimming advisories would have on Vermont’s overall economy

12. Peak season for algal blooms • Algae grows most during the warm summer months • The peak blooms often coincide with peak months for water recreation and tourism

13. Blooms tend to occur at times when turbulent storms are followed by mild weather. (Chorus & Bartram, 1999)

14. Wind accumulation (Chorus & Bartram, 1999)

15. Objectives • Determine the most common routes of exposure. • Evaluate current and alternative monitoring systems. • Develop recommendations to improve efficiency in order to minimize risk and negative economic impacts.

16. Findings • 60% of cyanobacteria are toxic • Most species contain a slew of toxic & non-toxic strains • Routes of exposure • Ingestion – most significant for recreation • Inhalation – most severe health effects • Dermal contact – least severe health effects

17. Findings continued • Allowable dose is based on healthy adults • Certain demographic groups may be at a higher risk for adverse effects • Studies on long-term effects are limited

18. Findings continued • Cyanobacteria have a cumulative effect with multiple doses (swimming 7 days in a row) • Most common adverse health effects • Lung infection, pneumonia • Vomiting • Sore throat • Blistering around the mouth • Darrhea • Skin rash

19. Findings continued • Lack of comprehensive data • Need common management plan for Quebec and Vermont in regards to the Mississquoi Bay • Public education is important

20. Conclusions • There is a lack of a comprehensive knowledge base for timing, duration, and location of potentially hazardous blooms. • Human health is more important than the impact beach closures and swimming advisories would have on Vermont’s overall economy. • Outdoor enthusiasts who visit longer and more often, are more likely to suffer from chronic exposure.

21. Recommendations • A need for continued monitoring • If detailed research analysis does not exist, the following framework may be used

22. Table 1: Guidelines for potential risks and suggested actions for cyanobacteria contaminationa a Derived from Chorus & Bartram, 1999

23. Acknowledgements • Lake Champlain Basin Program • Mike Winslow • Staff scientist on the Lake Champlain Committee • Erica & Breck