news harmful algae bloom still issue in lake anna area

Harmful algae bloom still issue in Lake Anna area

virginia logoLocations within Lake Anna in Orange, Louisa and Spotsylvania counties continue to experience a harmful algae bloom (HAB).

“No-Swimming Advisory” Areas

Potentially harmful algae species detected in eight areas are at levels that present a moderate to high risk for human health effects. Coves, shallow areas, and shorelines in these areas are likely to have scum present. VDH is issuing or continuing a human health advisory for these areas and the public should avoid swimming in these vicinities:

  • Upper Pamunkey Branch east of Rt. 522 bridge (38.14309, -77.91724)
  • Upper-Middle Pamunkey Branch at Simms Point/Harris Lane (38.13942, -77.89372)
  • Lower-Middle Pamunkey Branch at Rt. 719 “Dillard’s Bridge” (38.13505, -77.8661)
  • Lower Pamunkey Branch at Lake Anna State Park Beach (112324, -77.833099)
  • Upper North Anna Branch near Goldmine Creek and “the Sandbar” (38.11517,-77.93754)
  • Middle North Anna Branch at Rt. 719 Bridge (38.11063, -77.88568)
  • Lower North Anna Branch near Rose Valley Island (38.10347, -77.85698)
  • Fisherman’s Cove (38.0474, -77.74151)

“Harmful Algae Detected – Be Aware of Blooms” In These Areas

Potentially harmful algae species detected in two areas are at levels that present a low to moderate risk for human health effectsVDH is notifying the public of the bloom in these areas but current levels do not warrant a “no swimming” advisory. Be aware of the bloom as water conditions may change quickly in these areas. Avoid contact with the water if scums appear on the water surface in these vicinities:

  • Upper-Middle North Anna Branch at Rt. 522 Bridge (38.11607, -77.91367)
  • Christopher Creek Branch north of Rt. 522 Bridge (38.10049, -77.89427); based on 9/5 samples – continued advisory

Area signage to warn the public of areas currently under advisory include area marinas and private lots where permission was granted.

To review areas where sampling for harmful algae occurred but levels were at low or non-detect levels, visit the Harmful Algae Map.

Most algae species are harmless; however, some species of cyanobacteria (also known as blue-green algae) may produce irritating compounds or toxins. Some symptoms of cyanobacteria exposure include skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting and diarrhea. All samples on Sept. 25 were screened for two toxins and results were all below the levels that may pose a health risk.

Algae blooms can occur when warm water and nutrients combine to make conditions favorable for algae growth. These conditions have occurred recently, particularly excessive rain. Rain typically results in nutrient-runoff from the land that can trigger algae blooms in natural waters. Surface scums that are green or blueish-green should be avoided, as they are more likely to contain toxins. Scums are more likely to occur in coves, shallow areas, or along the shoreline.

To report scum sightings, please submit your observations to the online HAB report and include a picture. While the HAB Task Force does not have the resources to respond to and sample all scum sightings, it will share ‘crowd-sourced’ scum reports which are submitted through the online HAB report in the HAB Map for public awareness.

Properly cleaned fish fillets which are cooked to proper temperature are considered safe to eat; providing the fish is skinned and internal organs are discarded. Research suggests waterbodies with long-term, recurrent toxic algae blooms can result in algal toxin accumulation in the fillet of fish; however, toxins have not been detected above safe swimming levels in Lake Anna.

The Virginia Harmful Algal Bloom Task Force, which includes the Virginia Department of Health, Virginia Department of Environmental Quality (DEQ), and the Old Dominion Phytoplankton lab, will continue to monitor water quality in the lake. VDH and DEQ will determine the sampling plan for the autumn months and will update the Lake Anna HAB webpage with the schedule, once it is available. Advisories may be lifted following two consecutive weeks of acceptable levels for algal cell counts and/or toxin concentration. For information on acceptable algae levels, see the Virginia Department of Health Recreational Advisory Guidance for Microcystin/Microcystis at

To prevent illness, people should:

  • Avoid contact with any area of the lake where there is scum or an advisory sign is posted.
  • Do not allow children or pets to drink from natural bodies of water.
  • Keep children and pets out of the areas experiencing a harmful algae bloom and quickly wash them off with fresh water after coming into contact with algae.
  • If you or your animals experience symptoms after swimming in or near an algal bloom, seek medical/veterinarian care.
  • Suspected HAB-related health-related effects following exposure to a bloom, may be reported to the Virginia Harmful Algal Bloom Hotline at 1-888-238-6154. Do not report health effect to the online HAB report form.
  • To learn more about harmful algae blooms or to report an algae bloom or fish kill, submit an online HAB report visit


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