RICHMOND, VA – The North Anna and Upper Pamunkey Branches, including Terry’s Run, of Lake Anna in Orange, Louisa and Spotsylvania counties are experiencing a harmful algae bloom (HAB).
The public is advised to avoid contact with specific areas of the lake until algae concentrations return to acceptable levels. Some harmful algae, called cyanobacteria, can cause skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting and diarrhea. The area to avoid can be seen on an interactive Harmful Algal Bloom map. A status report containing the updated advisory areas may be viewed at Lake Anna HAB Status Report 7.15.22.
Samples results provided on July 14 from collections on July 7 indicated that at six locations in the North Anna and Pamunkey Branches, swimming advisories are necessary due to unsafe levels of cyanobacteria, which have the potential to produce toxins. People and pets are advised to avoid swimming, windsurfing and stand-up-paddle-boarding, as well as other activities that pose a risk of ingesting water. Activities such as boating may continue with proper precaution in advisory areas. Follow-up monitoring above Route. 208 on the lake is planned (weather permitting) for the first week of August.
The samples collected at the Lake Anna State Park beach indicated cyanobacteria densities were at acceptable levels and do not necessitate a swimming advisory. Cyanobacteria and cyanotoxins were detected at this site, but were well below safe swimming levels.
The sections of the lake currently under advisory:
Pamunkey Branch – Upper (including Terry’s Run) and Middle
North Anna Branch – Upper and Middle
Algae blooms can occur when warm water and nutrients combine to make conditions favorable for algae growth. Most algae species are harmless, however, some species may produce irritating compounds or toxins. Avoid discolored water or scums that are green or bluish-green because they are more likely to contain toxins.
To prevent illness, people should:
The Virginia Department of Health (VDH) and the Virginia Harmful Algal Bloom Task Force, which includes the VDH, the Virginia Department of Environmental Quality, and the Old Dominion University Phytoplankton Laboratory, will continue to monitor water quality in the lake. In general, advisories will be lifted following two consecutive test results with acceptable levels for algal cell counts and/or toxin concentration. An advisory may be lifted or maintained at the discretion of the health department. For example, after one test an advisory may be lifted if results are within safe levels for swimming if other information indicates exposure or human health risk is low.
The Harmful Algal Bloom map is updated to reflect the HAB advisory status of Lake Anna. The recent advisory extent is summarized in the Lake Anna HAB Status Report 7.15.22. For more information visit www.SwimHealthyVA.com.
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