Toxic Algae and Cyanobacteria in Recreational Waters. Rang Cho Miriam Moritz

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1 Toxic Algae and Cyanobacteria in Recreational Waters Rang Cho Miriam Moritz

2 Algae Large, diverse group of eukaryotic organisms Contain chlorophyll and/or other pigments green, brown or red colour Perform oxygenic photosynthesis Unicellular or colonial Can proliferate intensely in eutrophic waters, but do not form thick scums Toxic species: Dinoflagellates, Nanoflagellates, Diatomes, Haptophytes

3 Cyanobacteria Gram-negative bacteria Sizes from 1µm (unicellular) to >30µm (multicellular) Perform oxygenic photosynthesis Able to fix nitrogen in the dark world-wide 6 genera and at least 13 species identified

4 Cyanobacteria (2) gas-vesicles to regulate cell buoyancy Produce algal blooms in eutrophic waters 75% of these blooms contain toxins Toxin producing strains: Anabaena spp. Microcystis aeruginosa Nodularia spp.

5 Human health effects of Cyanobacteria and Algae in recreational Waters Exposure: dermal contact, ingestion, inhalation/aspiration Acute symptoms: irritation of skin, mucous membranes, ears, eyes and throat; fever; diarrhoea; vomiting Chronic symptoms: damage of the liver, tumor promotion Algal toxins: Brevetoxin, Ciguatoxin Cyanotoxins: Microcystin, Anatoxin, Saxitoxin

6 Toxic Algae: Dinoflagellates Flagellated, primarily marine algae Free-living or symbiotic Accessory pigment: xanthophyll red Examples: Pfiesteria spp., Karenia brevis Produce powerful toxins causing extensive fish kills (also affected: marine mammals, birds, humans) Responsible for Red Tide : Immense algal bloom composed of red-pigmented Dinoflagellates Most important toxin: brevetoxin (K. brevis)

7 Dinoflagellates and Red Tides

8 Case 1: Occupational Exposure to Aerosolized Brevetoxins during Florida Red Tide Events: Effects on a HealthyWorkerPopulation (Backer et. al, 2005) Location: Beaches in Sarasoto or Manatee Counties, Florida Subjects: 28 full-time lifeguards, age >18, physically fit 6h exposure to marine aerosols (different exposure levels) environmental monitoring: concentration of brevetoxin in air and water K. brevis cell count Symptoms and respiratory effects study: questionnaire comprising questions about demographics, pulmonary health history and upper and lower pulmonary symptoms before and after each exposure period Pulmonary function tests (spirometry)

9 K. brevis Results: Increase in upper airway irritation (eye and throat irritation, nasal congestion, cough) and headaches was reported No increase in lower respiratory symptoms (chest tightness, wheezing, shortness of breath) No detection of changes in pulmonary function Conclusion: for healthy people exposure to low levels of brevetoxin leads to temporary discomfort No acute adverse effect on pulmonary function Brevetoxin

10 Case 2: Health effects of exposure to cyanobacteria due to recreational water-related activities. (Pilotto et al., 1997) location: 3 lakes and 1 river located in South Australia, New South Wales and Victoria, Australia Subjects: 852 randomly selected beach-visitors, age >6, majority age of 20-29, 2/3 men, exposed during swimming Water Analysis: Cyanobacterial cell counts, toxin analysis Symptoms and effects study: questionnaire recording recreational water activities, duration of water contact, health status before and on the day of exposure and of the following 7 days Microcystin

11 Results: Symptoms reported: diarrhoea, vomiting, flu symptoms, skin rashes etc. Probability for illness for people who were exposed to water was 3x higher than for control group Occurrence of illness significantly related to duration of exposure and to cell density, no relationship to microcystin concentration Cell counts between <5000 to >80,000 cells/ml Conclusions: Presence of cyanobacterial blooms in recreational water is associated with human diseases Currently accepeted threshold in Australia (20,000 cells/ml) too high

12 Management of Cyanobacteria and Algae provision of adequate public information Design of monitoring programmes Preventative and Remedial Measures: Several approaches: clays, herbicides, artificial turbulence, dinoflagellate parasites May have adverse ecological effects Long-term measure: minimization of nutrient input through human activities (agricultural run-off, inadequate sewage treatment etc.)

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