Update: Harmful Algae Bloom on Pamunkey, North Anna Branches of Lake Anna
Locations within Lake Anna in Orange, Louisa and Spotsylvania counties are experiencing a harmful algae bloom (HAB). Some harmful algae, called cyanobacteria, can cause skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting and diarrhea. The public is advised to avoid contact with the lake in some areas until algae concentrations return to acceptable levels. Advisory signs have been posted at some areas using buoys. Some signage has been posted at area marinas and private lots fronting “no-swimming advisory” locations where permission could be granted.
On Sept. 5, samples were collected at sites collected previously in August and included multiple new sites on the Lake south of Rt. 208 Bridge. A summary of the current advisories in place are below.
“No-Swimming Advisory” Areas
Potentially harmful algae species were detected in two areas on Sept. 5 at levels that present a moderate to high risk for human health effects. One additional location listed below was sampled previously on 8/28 and the advisory remains in place. Coves, shallow areas, and shorelines in these areas are likely to have scum present. VDH is issuing a human health advisory and the public should avoid swimming in these vicinities that include the GPS coordinates:
- Upper Pamunkey Branch of Lake Anna east of Rt. 522 bridge (38.14309, -77.91724)
- Upper North Anna Branch of Lake Anna near Goldmine Creek and “the Sandbar” (38.11517,-77.93754)
- Issued Aug. 28; remains in effect – Fisherman’s Cove (38.0474, -77.74151)
“Harmful Algae Detected – Be Aware of Blooms” In These Areas
Potentially harmful algae species were detected in four areas at levels that present a low to moderate risk for human health effects. VDH is issuing a public notification of a harmful algae bloom in these areas but current levels do not warrant the issuing of a “no swimming” advisory. The public should be aware of the bloom in these areas because water conditions may change quickly. Coves, shallow areas, and shorelines in these areas may have scum present. Avoid contact with the water should scums appear on the water surface in these vicinities that include the GPS coordinates:
- Upper-Middle Pamunkey Branch of Lake Anna at Simms Point/Harris Lane (38.13942, -77.89372)
- Lower-Middle Pamunkey Branch of Lake Anna at Rt. 719 “Dillard’s Bridge” (38.13505, -77.8661)
- Upper-Middle North Anna Branch of Lake Anna at Rt. 522 Bridge (38.11607, -77.91367)
- Christopher Creek Branch of Lake Anna north of Rt. 522 Bridge (38.10049, -77.89427)
Samples collected Sept. 5 at Lake Anna State Park Beach were at concentrations which should not pose a human health risk. To review areas where sampling for harmful algae occurred but levels were at low or non-detect levels please visit the Harmful Algae Map.
The next round of algae monitoring for Lake Anna is scheduled for late September depending upon the weather.
Most algae species are harmless; however, some species may produce irritating compounds or toxins. Species of cyanobacteria capable of producing several toxins were detected in the Sept. 5 samples. All samples were screened for two toxins but were below levels which 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. Discolored water or 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 please include pictures.
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. Some 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 Department of Health and the Virginia Harmful Algal Bloom Task Force, which includes the Virginia Department of Health, Virginia Department of Environmental Quality, and the Old Dominion Phytoplankton lab, will continue to monitor water quality in the lake. The next round of algae monitoring for Lake Anna is scheduled for late September depending upon the weather. 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 www.SwimHealthyVA.com.
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.
- If you suspect you experienced health-related effects following exposure to a bloom, contact the Virginia Harmful Algal Bloom Hotline at 1-888-238-6154
- To learn more about harmful algae blooms or to report an algae bloom or fish submit an online HAB report visit www.SwimHealthVa.com.