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Harmful Algal Bloom Spreads in Utah Lake

Utah Lake Harmful Algal Bloom Lincoln Marina, June 20, 2018
Lincoln Marina, June 20, 2018

The Utah County Health Department (UCHD) has issued a Warning Advisory for Utah Lake due to toxin levels that exceed health-based thresholds. UCHD advises people, their pets, and other animals to stay out of Provo Bay, Lincoln Marina, Sandy Beach, and the Utah Lake State Park Day Use area.

The Division of Water Quality (DWQ) conducted sampling on June 20, 2018, at eight Utah Lake sites. Toxin test-strip results from three of the sample sites exceeded the recommended health advisory threshold for microcystins, a cyanotoxin that can cause liver damage. Utah Public Health Lab enzyme-linked immunosorbent assay (ELISA) testing confirmed the toxin test-strip results.

The health department is posting warning signs at the affected locations. DWQ scientists collected additional samples at these sites on June 25, 2018.

While some areas on Utah Lake are not currently affected by the blooms, algae may move or disperse depending on temperature, wind, and weather. Recreationists are advised to be mindful of conditions, as they may change over the course of the day.

Utah Lake Harmful Algal Bloom Sandy Beach, June 20, 2018
Sandy Beach, June 20, 2018

Warning Advisory for Portions of Utah Lake

A Warning Advisory indicates a moderate relative probability of acute health risk, a cell-count density of 20,000 – 10 million cells per milliliter (cells/ml), microcystin levels of 4-2,000 micrograms per liter (µg/L), or anatoxin-a levels above non-detect. Advisory actions:

  • Do not swim or water ski
  • Do not ingest the water
  • Keep pets and livestock away
  • Clean fish well and discard guts
  • Avoid areas of scum when boating

Toxin Test Results

 ELISA testing by the Utah Public Health Lab, followed by 10x dilutions on samples with microcystin concentrations greater than the upper limit of the test (5 micrograms per liter (µg/L), showed the following microcystin levels in the June 20, 2018, Utah Lake water samples:

  • Lincoln Marina: >50.0 micrograms per liter (µg/L)
  • Sandy Beach: >50.0 µg/L
  • Utah State Park Day Use Area: 17 µg/L
  • Swede Access: 4.3 µg/L

Cyanobacteria Cell Count Concentrations

All samples from June 20, 2018, were dominated by Dolichospermum, a  toxic genus of cyanobacteria. Cell-count densities exceeded health-based thresholds. The following cell counts were for toxigenic cyanobacteria only.

  • Lincoln Marina: >2.5 million cells per milliliter (cells/ml)
  • Sandy Beach: >1.4 million cells/ml
  • State Park Day Use Area: >539,000 cells/ml
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