Blue Green Algae in New Brunswick Lakes: Questions and Answers
What are blue green algae (cyanobacteria)?
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Blue green algae are bacterial organisms that are photosynthetic and are often found in many types
of water systems including lakes, rivers and wetlands.
Under the right environmental conditions (including: warm, slow moving, shallow water, sunlight and
a nitrogen/phosphorous food source), high growths of blue-green algae can occur and create
blooms (scum layer) on the water surface. Blooms range in colour from dark green to yellowish
brown.
Blooms can produce toxins which can impact health of animals and humans. The toxins are varied in
species, with microcystin toxin being the most predominant.
Has blue green algae been present in NB?
Blue green algae has been present in some lakes in New Brunswick in previous years. With the right conditions,
the organisms can grow in large quantities. Within only a few days a bloom can cause clear water to become
cloudy while the blooms float to the surface. These blooms can look like foam, scum, or mats on the surface of
fresh water or ponds and are blue, bright green or red in colour. Some look like paint streaks on the water, while
others many not affect the appearance directly. Some factors important for bacterial growth include:
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Warmer water temperatures;
Amounts of light and length of daylight;
Wind and water currents; blooms often occur in slow moving shallow water
Sufficient nutrients; and
pH
What are possible health effects from blue green algae?
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Skin contact to any blue green algae may cause irritation and result in hives, rashes, skin blisters,
etc.
Some types of blue green algae produce natural toxins, or poisons. These toxins, if swallowed
through drinking the water, or inhaled (ex. through inhaling water droplets from recreational activities
such as water skiing, boating, watering lawns, etc.) could cause illness in people and animals.
Children and immuno-compromised individuals are at a higher risk for the more severe effects from
exposure to the toxins.
What happens if I come into contact with water contaminated with blue-green algal toxins?
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Relatively few incidents of human poisoning have been reported. People don't usually drink water
contaminated with blue-green algae because of the scum and the accompanying smell (fresh
blooms smell like newly mown grass; older blooms smell like rotting garbage), however, people
could accidentally swallow contaminated water while swimming or are involved in other recreational
activities.
If you swallow contaminated water, you may experience headaches, fever, sore throat, dizziness,
stomach cramps, nausea, diarrhea and vomiting. These symptoms may last for several days.
If you swim in contaminated water, you may get itchy and irritated eyes and skin, as well as other
hay fever-like allergic reactions.
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If you suspect you might have come into contact with algal toxins in the water, you should remove
any affected clothing and rinse thoroughly in clean water after coming ashore. Persons experiencing
symptoms or health affects after recreational contact with affected water should seek medical
advice.
How harmful are algal toxins?
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Although many people have become ill from exposure to freshwater blue-green algae toxins, death
from algal-contaminated drinking water is unlikely to occur given that water resources are usually
effectively
managed to control taste, odour and other algae-related problems. It's possible that extended
exposure to low levels of toxins could have long-term or chronic effects in humans.
Children are at greater risk than adults of developing serious liver damage should they ingest high
levels of toxins, mostly because of their comparatively lower body weight.
Should pets or livestock drink water containing blue-green blooms?
If livestock or other domestic animals have no other source of drinking water, they may be poisoned by drinking
water from open water bodies, such as lakes or ponds, contaminated with toxic strains of blue-green algae. In
some cases, wind may blow the algae floating on the surface towards the shoreline. Young livestock usually drink
closer to the shore and are more likely to be poisoned. Animals are not more sensitive than people to the effects
of the toxins; they are simply not as concerned with the way water looks or smells before they drink it. Death is
usually caused by damage to the liver or to the nervous system, depending on which toxins were predominant in
the water.
Can I cook using water with blue-green algae in it?
No. Boiling water does not remove toxins from the water. As it is impossible to detect the presence of toxins in the
water by taste, odour or appearance, you must assume that they are present until testing is completed.
Can I use water contaminated with algal toxins for washing?
If there is a safe source of water available, don't use contaminated water for washing clothes or dishes. If no
alternative supply is available, use rubber gloves to avoid direct contact with the water. Bathing or showering in
water contaminated with algae or algal toxins should be avoided, as skin contact with the algae can lead to skin
irritation and rashes.
Can I eat fish from water contaminated with algal toxins?
Toxins can accumulate in the tissues of fish, particularly in the internal organs (liver, kidney, etc.). Levels in the
tissues depend upon the severity of the bloom in the area where the fish are caught or collected. Caution should
be taken when considering the consumption of fish caught in areas of a water body where major blue-green algal
blooms occur; in particular, the internal organs of the fish should not be eaten, and all fish should be thoroughly
rinsed with potable water before cooking and eating.
Can water containing blue-green algae blooms be used for recreational activities?
Blooms in recreational bodies of water are usually associated with unpleasant odours and offensive appearance
on shorelines as the scum accumulates and decays. Although blue-green toxins are probably not absorbed
through the skin, they can cause skin irritation. The toxins, if present, can be absorbed from the water via
ingestion or can become airborne and be absorbed via inhalation. Individuals should avoid swimming and other
water-related activities in areas with dense blooms.
Why are Public Health Advisories for recreational waters issued?
Advisories are issued to inform local recreational water users so that they can make informed decisions on water
use in the affected area, as well as make them more aware of looking for the formation of highly visible blooms
and scum, which pose the most risk. Since conditions may change in a matter of hours, having this awareness is
crucial to making good decisions and staying safe.
When is it safe to use the water?
The Department of Health encourages the public to be active and enjoy the outdoors but be aware that bluegreen algal blooms can be unpredictable. Toxins may persist in the water for several weeks and the time that it
takes to decrease is dependent on numerous factors. Blooms can appear quickly. Even if you can't see a bloom
floating on the surface of the water, that doesn't mean one isn't present in the water - the bloom could be
suspended at various depths in the water where you can't see it. Water quality should be observed prior to
entering and where blue-green algae is suspected (surface scum and/or discoloured water) it is recommended
that recreational water use be avoided.
For more information, please visit the following websites:
Department of Environment and Local Government:
http://www2.gnb.ca/content/gnb/en/departments/elg/environment/content/water/content/algae.html
Health Canada:
http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/guide_water-2012-guide_eau/index-eng.php#a6