Cyanobacteria can create toxins within their cells that may be hazardous, if not deadly, for many humans and animals. Knowing what kind of cyanobacteria are present in a bloom will not indicate if toxin is present. The cyanobacteria must have toxin-producing genes in their DNA. Toxin producing genes can be identified by a qPCR test. EPA has set health advisories for some cyanotoxins, but not all known or present cyanotoxins in Idaho are covered by the health advisories. Health advisories are based on levels found in the “finished” drinking water, not raw water. When a bloom occurs in your source water, the best action to prevent or reduce toxin release is to try and remove the intact cells from the treated water. For toxin already present or released during treatment, the best-known treatments to remove or break down the toxins into less dangerous forms can be found at EPA’s Summary of Cyanotoxins Treatment in Drinking Water website. | |
Microcystis taken from Payette River (9/13/2022). Identified and photographed by Dr. Barry Rosen of the Florida Gulf Coast University. | |
The most common cyanotoxin identified in Idaho are microcystins. Microcystin toxins can be produced by Dolichospermum, Fischerella, Gloeotrichia, Nodularia, Nostoc, Oscillatoria, Microcystis, and Planktothrix cyanobacterial cells. The most understood health effects from microcystin are damage to the liver, kidneys, and reproductive system. Signs of exposure can be abdominal pain, nausea, vomiting, headache, diarrhea, sore throat, and blistering around the mouth. EPA has established a 10-day health advisory level for microcystins in drinking water. Children under the age of 6 years old are not expected to have health effects from microcystin if the levels are less than 0.3 ug/L and exposure does not occur longer than 10 days. For everyone 6 years and older the microcystin health advisory level is 1.6 ug/L. | | |
Dolichospermum flos-aquae taken from Payette River (9/13/2022). Identified and photographed by Dr. Barry Rosen of the Florida Gulf Coast University. | |
Anatoxin is the second most common cyanotoxin identified in Idaho. Anatoxins are most associated with Chrysosporum (Aphanizomenon) ovalisporum, Cuspidothrix, Raphidiopsis, Cylindrospermum, Dolichospermum, Microcystis, Oscillatoria, Planktothrix, Phormidium, Dolichospermum flos-aquae, A. lemmermannii Raphidiopsis mediterranea, Tychonema, and Woronichinia. The most understood health effects of anatoxin-a are to the nervous system that includes numbness, tingling, burning sensations, drowsiness, salivation, and difficulty in speech. EPA hasn’t set a health advisory for anatoxin at this time.
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Cylindrospermopsin and Saxitoxin | |
Aphanizomenon flos-aquae taken from Payette River (9/13/2022) and identified and photographed by Dr. Barry Rosen of the Florida Gulf Coast University. | |
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Cylindrospermopsin production has been connected to Raphidiopsis, C. raciborskii, Aphanizomenon flos-aquae, Aphanizomenon gracile, Aphanizomenon ovalisporum, Umezakia natans, Dolichospermum bergii, Dolichospermum lapponica, Dolichospermum planctonica, Lyngbya wollei, Rhaphidiopsis curvata, and Rhaphidiopsis mediterranea. Health effects may include vomiting, bloody diarrhea, fever, and headache. It is known to damage the liver and kidneys. The EPA 10-day Health Advisory for children under the age of 6 years old is 0.7 ug/L. For everyone 6 years and older the health advisory level is 3.0 ug/L.
Saxitoxin is best known in marine environments but has also been identified in freshwater. It is a neurotoxin commonly associated with paralytic shellfish poisoning. In freshwater cyanobacteria, it has been associated with Aphanizomenon flos-aquae, Dolichospermum circinalis, Lyngbya wollei, and Planktothrix species. Symptoms will occur rapidly and can include nausea, vomiting, headache, muscle weakness, dizziness, and paralysis.
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- Taste and Odor Problems – Geosmin and MIB
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Regional HAB Advisory News | |
The Idaho Department of Environmental Quality will be hosting a free virtual Drinking Water Operator training in December. The expected date is Thursday, December 15 and the course is being submitted for 0.6 CEU approval. Please be on the lookout for the email announcing how to register for the course. | | | | | |
