Cyanotoxins & HumanHealth

Alison ReeveJiaxin Yu

Marshall AmbrosRachel Beauregard

Steve Hoffmann

Problem StatementCyanobacteria are capable of producing toxins and have been linked to human health concerns

Objectives• Study the behavior of cyanotoxins in the environment and the human body•Thoroughly investigate cyanotoxin's effects on human health in the Lake Champlain Basin. •Determine precautionary measures to prevent the toxins from further impacting human life and the environment.

Cyanobacteria History

They’ve been around for 2 billion years Research on cyanobacteria toxicity began

19th century Incidence of disease in 20th century caused

by: Population pressure Global warming Eutrophication of surface waters Increased monitoring/awareness Unknown factors?

Charmichael 2001

Cyanotoxin Receptors

Humans Livestock Ducks Zooplankton (some indication) Fish? Shellfish?

DeMott 1991, EPA 2005

Exposure• Eating contaminated

food• Drinking contaminated

water• Swimming or dermal

exposure• Inhalation

• ALS• Gastroenteritis, liver

and kidney damage, death

• Skin rashes• Irritation of eyes, nose,

throat, skin, and respiratory tract

Cyanobacteria

Prokaryotic Photosynthesizing Important primary producer in aquatic

ecosystems Nuisance “blooms” in eutrophic environments Some species produce toxins

Eutrophication• Phosphorus loading

• Agricultural runoff • Stormwater runoff

• Algae Blooms

http://upload.wikimedia.org/wikipedia/commons/b/bb/DairyCattle.jpg

http://www.belaireks.org/images/Planning%20_%20Zoning/Stormwater.jpg

Algae Blooms

• Other Contributing Factors• Nitrogen concentrations• Water temperature• Light• Morphology of the impoundment

• Effects on Ecosystem• Anoxia• Toxic Blooms

Toxic Cyanobacteria

2,000 species: ~ 40 known to produce toxins Anabaena spp. Microcystis spp. Planktothrix spp. Nostoc spp. Nodularia spumigena

Microcystis aeruginosa Planktothrix rubescens Nodularia spumigena

http://www.shigen.nig.ac.jp/algae/images/strainsimage/nies-0075.jpg

www.igb-berlin.de/.../phycology/algae2.jpg www.icb.ufmg.br/big/lgar/img_t3.jpg http://www.soes.soton.ac.uk/staff/tt/nf/pics/nodusp6.jpg

Cyanotoxins Neurotoxins

Anatoxin-a Anatoxin-as Saxitoxin β-Methylamino-L-alanine (BMAA)

Hepatotoxins Microsystin-LR Nodularin-R

Cytotoxins Cylindrospermopsin

Gastrointestinal and dermatotoxins Aplysiatoxin Lyngbyatoxin a

Anatoxin-aAnatoxin-as

Saxitoxin

Nodularin RMicrocystin LN

Cylindrospermopsin Aplysiatoxin

BMAA

Neurotoxins Anatoxin-a mimics acetylcholine

Anatoxin-as is structurally different from Anatoxin–a and is highly toxic

Saxitoxin is usually associated with red tides in marine ecosystems Responsible for paralytic shelfish poisoning Been detected in some freshwater species

AcetylcholineAnatoxin-a

Hepatotoxins

• Cyclic peptides• Cause liver damage• Long term exposure can lead to liver cancer

Past Cases

• First known linked case found in Guam• Caruaru, Brazil, Summer 1996

• Dialysis center used water contaminated with microcystins

• 23 patients died in first 2 weeks, 37 more within 5 weeks

Funari E, Testai E. Toxigenic cyanobacteria from marine, brackish and freshwaters. Chart. Critical Reviews in Toxicology, Feb2008; 38(2):98 Available from: Academic Search Premier, Ipswich, MA. Accessed March 20, 2010.

Funari E, Testai E. Toxigenic cyanobacteria from marine, brackish and freshwaters. Chart. Critical Reviews in Toxicology, Feb2008; 38(2): 101 Available from: Academic Search Premier, Ipswich, MA. Accessed March 20, 2010.

BMAAneurotoxin

• Caused by over 30 species of cyanobacteria:• Ex. Microcystis, Anabaena, Nostoc, Planktothrix

• Can cause motor neuron disease or death• Accumulates in brain tissue• Found in Guam and linked to ALS

Amyotrophic Lateral Sclerosis(ALS)

• Neurodegenerative disease• About 2 per 100,000 people in US• Can be caused by the neurotoxin BMAA• Symptoms

• Muscle weakness (including speech muscles)• Twitching and cramping of muscles• Trouble with speech• Shortness of breath, trouble swallowing• Death by suffocation

Parkinson’s Disease(PD)

• Neurodegenerative Disease• Symptoms

• Rigidity of muscles, slowing of movement• Muscle spasms or tremors• Loss of smell, blinking, smiling• Speech changes (soft, monotone, repetition)• Dementia in later stages

Alzheimer’s

• 7th leading cause of death• Most common form of dementia• Destroys brain cells leading to memory loss,

confusion, changes in personality, mood, behavior, problems with language

Primary Liver Cancer (PLC)

Most common form of liver cancer• About 90% of liver cancer patients have this form

• Low 5-year survival rate• 1.6 million people are diagnosed every year

Water Treatment Techniques

Must use several methods in conjunction to eliminate both cells and toxins

Coagulation/flocculation/sedimentation are good first steps, followed by:

filtration with membrane, sand or activated charcoal Final treatment with UV light or ozone

• Burlington water intake is located in deep water, forty feet below the surface. Cyanotoxins and cells accumulate in shallows and near water surface.

Still Unknown

• Why certain species of cyanobacteria produce toxins only sometimes

• If chronic diseases are actually caused by cyanotoxins

• What causes algal blooms• What factors besides shallow, stagnant water and

phosphorus loading

• How to effectively remove cyanotoxins from water

Exposure in Lake Champlain

• Algal blooms in St. Albans Bay and Mississquoi Bay – not all toxic

• Drinking water- only during major blooms• Ingestion or dermal contact

• Swimming- dermal contact• Can lead to acute or chronic diseases, none

reported thus far• Dog deaths from swimming• Only problem in summer

Algae via Remote Sensing

Can detect different types of blooms using aerial imagery Each bloom has a different color

Color change from Southern to Northern lake due to blooms in the summer Apparent on Google Maps

Potential Cyanotoxin Producing Species in Lake Champlain

  2003 Frequency of Occurrence - Percent of Samples

Taxon Main Lake South Lake Missisquoi Bay St Albans and other Northeastern Bays

Anabaena flos-aquae 83 29 57 53

Anabaena spp. 51 50 43 58

Microcystis aeruginosa 47 43 94 56

Coelosphaerium spp. 34 29 4 44

Gloeotrichia spp. 1 0 5 9

Aphanizomenon flos-aquae 73 43 22 49

Samples Analyzed 102 14 175 45

Lake Champlain’s Algae Problem

Not sure what causes toxicity• Algae blooms are caused by:

• P/Nutrient/N cycles thrown off• Lack of/not enough BMP’s in place• Missisquoi Bridge

• Turtle Habitat

• Urban/Residential runoff• Transportation

Wetlands

Many wetlands have reached their holding capacities for nutrients

LCBP wetland preservation Nutrients released when wetlands are

destroyed Could construct more in key areas, but it

would only be a temporary fix

Recommendations

The Three Aspects

• Prevention

• Increase public and government awareness

• Continuation of research and monitoring

Prevention

To prevent cyanobacterial blooms

To prevent human exposure to cyanotoxins

Cyanobacterial Bloom Prevention

Prioritization

Riparian Buffers

Constructed Wetlands

Human Exposure Prevention

Water treatment methods and technology

Coagulation/Flocculation/filtration + UV light treatment

Provisional guidelines (World Health Organization)

Public Awareness

Get Connected Clean Water Action

Be Informed

Demand Actions

Monitoring

Areas with repetitive cyanobacterial blooms

Areas with cyanotoxin exposure reports

Research

The behaviors and mechanisms of the cyanobacteria and toxins in both water and the human body.

To develop effective water treatment

Questions?

Resources:

DeMott, W.R. et al. (1991) Effects of Toxic Cyanobacteria and Purified Toxins on the Survival and Feeding of a Copepod and Three Species of Daphnia. Carmichael Limnology and Oceanography, 36, 7, 1346-1357.

“International Symposium on Cyanobacterial Harmful Algal Blooms”. 2005 U.S. Environmental Protection Agency <http://www.epa.gov/cyano_habs_symposium/>

Carmichael, WW. (2001) Health Effects of Toxin-Producing Cyanobacteria: “The CyanoHABs”. Human and Ecological Risk Assessment, 7, 5, 1393-1407.

Parkinsons.org

Alsa.org

Alz.org

LCBP.org