Cyanobacteria blooms & Controls
Cyanobacteria enter a rapid phase of cell division due to high concentration of nutrients especially phosphorus and nitrogen in the rivers, lakes & recreational waters.
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Also commonly referred to as harmful algal blooms (HABs or cyanoHABs) due to their vast ecological impacts and ability to generate metabolites like cyanotoxins
Taken from orbit in October 2011, the worst algae bloom that Lake Erie has experienced in decades. Record torrential spring rains washed fertilizer into the lake, promoting the growth of microcystin-producing cyanobacteria blooms
(credit: Wikipedia)
Potential causes for Cyanobacteria Blooms
Cyanotoxin
Cyanotoxins are toxins produced and contained within the cyanobacterial cell, releasing into the surrounding water when cell death and lysis occurs
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The most commonly found cyanotoxin: Microcystins, Cylindrospermopsin, Anatoxins and Saxitoxins
Human exposure to cyanobacteria &Health issues
Direct contact
activities like swimming in contaminated rivers or lakes
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Skin irritation
Inhale cyanotoxins
airborne droplets or mist of toxins
Drink/swallow contaminated water
drink or swallow contaminated water
Eat contaminated food
food/ supplement containing toxins
Nose/Lungs irritation
breathing difficulties
Stomach pain
Headache
Vomiting
Diarrhea
Liver damage
Neurological symptoms
Liver damage
Headache
Warning system
Most drinking utilities relies on warning system to gain enough responding time to the cyanobacteria bloom.
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With exsiting warning system, individual water bodies are identified and marked with various alerting signs based on the levels of cyanobacteria contamination.
How to Control HABs Blooms?
Effective preventions and proactive managements that reduce nutrient inputs into water bodies currently are the most ideal strategies suppressing cyanobacterial blooms
Governmental External nutrients controls
Legislations
e.g. 1972 Clean Water Act
Established institutions
e.g.EPA(Environment Protection Agent), USDA(United State Department of Agriculturer)
Setting standards
e.g. Total Maximum Daily Load (TMDL)
Nutrient credits trading system
How to remove HABs & cyanotoxins from waterways?
Conventional water treatment (consisting of coagulation, sedimentation, filtration, and chlorination) can generally remove intact cyanobacterial cells and low levels of cyanotoxins from source waters.(EPA)
*Chemicals like copper sulfates can kill cyanobacteria, but issues existed with this approach:
â‘ Releasing cyanotoxins ?
â‘¡ Clear uncompletely ?
â‘¢ itself present in large amount is toxic and harmful