Toxic & Nontoxic Algae
September 6, 1996


by Dr. William T. Barry
Water Quality Specialist


Because of the occurance of an undesirable species of blue-green algae in Klamath Lake, algae companies have, wisely, suspended harvesting. Even though noxious species can be distinguished from Aphanizomenon flos-aquae, companies will wait until the undesirable species is gone before resuming the harvest.

Some strains of Microcystis aeruginosa can be toxic and dangerous to human beings and to other animals. It is very fortunate, indeed, that the strain of Microcystis aeruginosa, presently in Klamath Lake, is not a killer strain.

As stated in a press release of 5 September 1996, some toxic strains, of some blue-green algae are so dangerous that a small quantity could kill a dog or a farm animal, Anabaena flos-aquae comes to mind.

The most recent test results, 5 September 1996, for the strain of Microcystis aeruginosa presently in Klamath Lake, have already demonstrated that, at worst, this strain is mildly toxic to nontoxic.

Consider, even more serious concrete evidence; it is known that numerous horses, cattle and dogs have been drinking Klamath Lake Water for the past month. Because the toxin is an exotoxin, an animal could be poisoned by drinking the water even if it did not consume any algae. Yet, there have been no casualties, no sick, no dead, nor dying animals.

During a bloom of toxic blue-green algae, Anabaena flos-aquae, in Long Lake (Spokane, Wa.) 1975, dogs and horses died in 20 to 40 minutes after drinking from the lake. More than 45 domestic animals died, including dogs, plus, and unknown number of deer, elk and other wild animals all in a matter of days.

In the Klamath Lake Area no animals are known to have died or even to have become sick. Yet, Microcystis aeruginosa has been present for at least a month. This strain of Microcystis aeruginosa is in Agency Lake, Klamath Lake, the irrigation ditches (canals) and in the Link River. Of course, animals have been drinking the water from these sources and of course they are ingesting Microcystis aeruginosa and/or the exotoxin.

A worst case scenario, based on the most resent test results (5 Sept. 96) is this strain of Microcystis aeruginosa is mildly toxic i.e., 27 to 47 millionths of a gram of toxin per gram of Microcystis aeruginosa, i.e., 27 to 47 mu.g/g, which will not poison dog, horse or cow.

Standards set by foreign countries, viz. Canada. need not be applied in the United States.

Of course, it is not wise to harvest until Microcystis aeruginosa is no longer present. Further, it is not wise to overreact, causing needless alarm.

It is hoped that this information will allay fear and anxiety. it should be a comfort to dog cattle and horse owners.

Any species of algae, especially the blue-greens, when in concentration, can be a skin irritant to some folks, sometimes; avoid swimming in dense algae!

A little learning is a dangerous thing
Drink deep, or taste not the Pierian spring
There shallow draughts intoxicate the brain
And drinking largely sobers us again.

Alexander Pope (1688-1744)

© 1996, Barry, Dr. W.T. All rights reserved.


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