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DOH-Hillsborough again cautions about blue-green algae at Lake Thonotosassa

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September 11, 2024

HILLSBOROUGH COUNTY – The Florida Department of Health in Hillsborough County (DOH-Hillsborough) is cautioning the public of the presence of blue-green algae in Lake Thonotosassa on September 11, 2024. Water sample testing is underway. Blue-green algae have the potential to produce toxins. Since environmental conditions can change at any time, it is important to exercise caution, even if presence of toxins has not yet been confirmed.

  • A blue-green algae Health Caution is issued when DEP sampling results show that a bloom has been visually detected and/or when sampling results indicate the dominant algal species to be cyanobacteria.
  • A blue-green algae Health Alert is issued when cyanotoxin is present.
  • A blue-green algae Health Alert is lifted once toxins are not detected according to the analyses obtained from DEP-coordinated resampling of the bloom or if 30 days have elapsed since the last sampling date.

See prior notice below


August 14, 2024

HILLSBOROUGH COUNTY – The Florida Department of Health in Hillsborough County (DOH-Hillsborough) is cautioning the public of the presence of blue-green algae in Lake Thonotosassa on August 14, 2024. Water sample testing is underway. Blue-green algae have the potential to produce toxins. Since environmental conditions can change at any time, it is important to exercise caution, even if presence of toxins has not yet been confirmed.

DOH-Hillsborough advises residents and visitors to take the following precautions:

  • Do not drink, swim, wade, use personal watercrafts, or come into contact with waters where there is a visible bloom.
  • Wash your skin and clothing with soap and water if you have any contact with algae, or discolored or water that smells unpleasant.
  • Keep pets and livestock away from the area to avoid any contact with water. Waters where algae blooms are present are not safe for animals. Pets and livestock should use an alternative source of water when algae blooms are present.
  • Do not cook or clean dishes with water contaminated by algae blooms. Boiling the water will not eliminate toxins.
  • Eating fillets from healthy fish caught in freshwater lakes experiencing blooms is safe. Rinse fish fillets with tap or bottled water, throw out the guts, and cook fish thoroughly.
  • Do not eat shellfish in waters with algae blooms.

The Florida Department of Environmental Protection (DEP) and partners collect algae samples from reported bloom locations. After samples are analyzed at their laboratory, the toxin results can be viewed on Protecting Florida Together or on DEP’s Algal Bloom Dashboard.