Pollution: Microcystins: Nova Scotia

Introduction to one of the dangerous organisms found in nutrient rich waters.

The blue-green algae or cyanobacteria are actually more closely related to bacteria than to algae. They are a normal part of an aquatic ecosystem. However; they multiply to dangerous levels when conditions and nutrient levels are right for their growth. It appears that these conditions are a ongoing part of our Carleton River system, stimulated by excessive nurients entering the system. Fortunately I did not find much information related to human deaths due to cyanobacteria, but people do become very ill . If you ever considered eating freswater clams in this area my advice, would be: NO! Any activities on the river system should be done with caution.

Microcystis aeruginosa(S)

Microcystis aeruginosa is a common species of cyanobacteria (often called blue-green algae) that blooms in the fresh and low salinity waters can become quite striking if it floats and forms a surface scum.

With continued cycling of the nutrients from the bottom, the blue greens will probably "return". Also, these blue green algae can fix atmospheric (dissolved) nitrogen as they have specialized cells called heterocysts that are able to carry out this process. It is the excess phosphorus in the summer and their ability to fix nitrogen that, in part, triggers summer growth. (S)

Because excess nutrients from past agricultural practices could be present in our aquatic sediments for years to come, it is important to take control of the situation now, especially since there are plans to expand locally and to spread these factory farms around the province. Ignorance is no excuse.

Microcystis aeruginosa (10x)

Microcystins can persist in water because they are stable in both hot and cold water. Even boiling the water, which makes the water safe from harmful bacteria, will not destroy microcystins. As a result of this threat, the Canadian government implemented a recommended water-quality guideline of 1.5 μg per liter of microsystin-LR (the most common hepatotoxin), and other countries will likely follow suit. (S)

Disease due to cyanobacterial toxins varies according to the type of toxin and the type of water or water-related exposure (drinking, skin contact, etc.). Humans are affected with a range of symptoms including skin irritation, stomach cramps, vomiting, nausea, diarrhea, fever, sore throat, headache, muscle and joint pain, blisters of the mouth and liver damage. Swimmers in water containing cyanobacterial toxins may suffer allergic reactions, such as asthma, eye irritation, rashes, and blisters around the mouth and nose. Animals, birds, and fish can also be poisoned by high levels of toxin-producing cyanobacteria. Cyanobacteria have been linked to illness in various regions throughout the world, including North and South America, Africa, Australia, Europe, Scandinavia and China. There are no reliable figures for the number of people affected worldwide. The only documented and scientifically substantiated human deaths due to cyanobacterial toxins have been due to exposure during dialysis. People exposed through drinking-water and recreational-water have required intensive hospital care.(S)

Factsheets on Chemical and Biological Warfare Agent:
Microcystins are hepatotoxic, causing necrosis and pooling of blood in the liver with the organ gaining up to 100% of its normal weight. Species of the cyanobacterium or blue-green alga Microcystis,M. aeruginosa. This organism is a public health concern because it can grow rapidly in water rich in organic matter during warm weather during the phenomenon of "algal blooms" the green filamentous masses found floating on the surface of water. The toxin concentrations in a M. diagnosable can quickly exceed safe levels. It is difficult for anyone except an expert to identify these microorganisms, so all algal blooms have to be treated as potentially hazardous. Microcystins are about as toxic as G-type nerve agents.
For more information http://www.cbwinfo.com/Biological/Toxins/Microcystins.html

If you are so inclined, here is the Algae Resource Database that will help identify specific algae species. You may need a microscope.
http://www.shigen.nig.ac.jp/algae/imageListQueryAction.do?photoType=1&className=All

Microcystins Pollution on the Tusket

Microcystins
Pollution on the Tusket