Utah Department of Agriculture and Food

How Do I Know if I Have A Toxic Bloom?


You can’t know for certain unless you have the water tested.  However, look for these differences between cyanobacteria and non-toxic green algae:


  • Cyanobacteria looks like pea soup, an oil slick, or like someone placed dye in the water. Cyanobacteria is potentially toxic under the right conditions (See right).


  • Filamentous (non-toxic) green algae often looks like a mass of green hair on the water (see below).


Links To Other Identification Resources

Field Guide to Algae (from Kentucky)



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            DEQ Focus

The DEQ collects samples from waterbodies to determine cyanobacteria or cyanotoxins exposure risks. Initial sampling of cell counts using the ELISA method is commonly conducted through the open water recreation season.

    UDAF Focus

Once elevated cell counts have been identified through testing; or reports of concerns have been received, UDAF will sample for cyanotoxins and provide data related to water used for agricultural purposes. UDAF will focus on livestock watering sources and the distribution of irrigation water.



When deciding how to determine sampling procedures, we need to understand the agricultural risks. In a lake, reservoir, or stock pond cattle may have access to the shoreline or the entire water profile if the waterbody is shallow. Rivers, streams, and canals are also often used as livestock drinking water sources.

What are we sampling for? Cyanotoxins


Where are we sampling?  When concerns of cyanotoxins have been identified an evaluation will be made to determine sampling locations. Samples should address all possible agricultural impacts including irrigation water, livestock and crops. Knowing possible animal access, additional water inputs, and water distributions are important factors when deciding where samples need to be taken.

  • Lakes, streams and stock ponds based on livestock access
  • Irrigation distribution systems


When are we taking samples? Sampling begins once a notice has been verified of potential harm from cyanotoxins. Notifications may come from testing data of high cell counts or reports of animal sickness or loss which may be linked to cyanotoxins.


Who will take the samples? UDAF staff including

  1. UDAF Water Quality Staff
  2. Watershed Coordinators
  3. Zone Coordinators and Planners
  4. Conservation District Supervisors
  5. Utah Water Watch


What is the protocol for collecting and handling samples?  

  • Handling Samples
    • Fill out sample data label (Attachment H) and correspond with bottle
    • Store on ice

Deliver within 24 hours to a specified lab



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Potential Harmful Effects--General

There are potential health impacts, some of them serious or lethal, to people and animals that come in contact with cyanotoxins. Cyanobacteria can disperse throughout or concentrate within the waterbody. Therefore, when a problem is present caution should be used throughout the entire water body and distribution of water sources.


  • Ingesting water with cyanotoxins or mats of cyanobacteria cells
    • Symptoms may include vomiting, lethargy, diarrhea, convulsions, difficulty breathing, and general weakness. There have been livestock deaths from toxic algae exposures and water consumption.


  • In some cases, animals may choose a cyanobacteria source over clean water, even if a clean water source is available. Animals may eat mats of cyanobacteria slime. Therefore, animals should be restricted from cyanobacterica sources and be provided a clean source of drinking water.

The above information applies to agricultural producers and private owners of large animal breeds. For accurate information about pets, please contact your veterinarian or your local county health department for more information.



  • Research has shown that cyanotoxins can bio-accumulate in tissue of aquatic organisms.  The amount of bioaccumulation will depend on the cyanotoxins present, toxin concentrations, exposure length, fish species, as well as other variables.
  • UDAF does not have jurisdiction over aquatic wildlife in public waters.  Wildlife within this state, including aquatic wildlife, falls within the jurisdiction of the Division of Wildlife Resources.   
  • UDAF licenses private aquaculture facilities and fee fishing facilities.  If a HAB occurs at an aquaculture facility or fee fishing facility, UDAF could confirm the presence of a HAB, and supply guidance on managing the HAB.


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Potential Harmful Effects--General

There are potential health impacts, some of them serious or lethal, to people and animals that come in contact with cyanotoxins. To date, most of the research has been focused on direct ingestion by humans and animals of water containing cyanotoxins. But what about if you water fruit, vegetable or edible herb plants with water containing cyanotoxins?

Potential Harmful Effects--Plants

Limited research is ongoing and data is inconclusive on cyanotoxin uptake in plant tissue.

  • Studies in controlled environments have shown that some plants can accumulate cyanotoxins.
  • Cyanotoxin uptake in plant tissue are more likely to accumulate with extended exposure. This is dependent on plant type, watering procedures, and length of exposure and whether the plants are grown hydroponically or in the soil.






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Utah Department of Agriculture and Food Publications

HAB three-fold Flyer/Brochure


2017 UDAF Algae Response Plan



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