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Ogden City 21st Street Pond Algal Bloom 2017

| Updates | Data |

Update September 20, 2017

The recreational warning issued September 8, 2017 on the Ogden City 21st Street Pond by the Weber-Morgan Health Department will remain in effect. Samples collected September 13, 2017 indicate anatoxin-a was detected at 1.0 µg/L based on toxin test strip results. This result exceeds the anatoxin-a warning advisory threshold in UDEQ-UDOH health advisory guidance. Additionally, cyanobacteria cell counts from the sample collected on September 8, 2017 was approximately 14,000 cells/ml which is less than the 20,000 cell/ml warning advisory. Although this indicator is below the threshold, the detection of anatoxin-a justifies the warning remain in place until it fully degrades. Often, when a HAB begins to recede is when cyanotoxins become greatest. Some toxins may remain after the bloom has dissipated.

Warning Advisory for Ogden City Pond

A Warning Advisory indicates a moderate relative probability of acute health risk, cell count density of 20,000 -10 million, 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 drink the water
  • Keep pets and livestock away
  • Clean fish well and discard guts
  • Avoid areas of scum when boating

Update September 8, 2017

News Release: Ogden’s 21st Street Pond Health Advisory

Weber-Morgan Health Department officials are posting signs to warn residents of a potential harmful algae bloom near the 21st Street Pond in Ogden. Health department staff collected a sample on September 8, 2017, after reports of a suspected bloom on the pond. Toxin strip testing of the sample was positive for anatoxin-a. Any results above non-detect for anatoxin-a trigger a warning advisory under UDOH and UDEQ health-based guidance.

Pet owners are advised to keep their animals away from the pond and not allow them to drink the water. Pet owners concerned that their animals have been exposed to cyanobacteria should contact their veterinarian.

The Weber-Morgan Health Department plans to collect another sample on September 11, 2017, to test for toxins. The sample will also be sent to the lab for cyanobacteria cell-count concentrations and genera identification.

Warning Advisory for the 21st Street Pond

A Warning Advisory indicates a moderate relative probability of acute health risk, cell count density of 20,000 -10 million, 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 drink the water
  • Keep pets and livestock away
  • Clean fish well and discard guts
  • Avoid areas of scum when boating