This has been a trying year at Lake Anna with high E. coli readings in the spring, hydrilla in late summer and early fall and an outbreak of harmful algae blooms recently.
While algae blooms are not unusual at the lake, this year’s outbreak included a variety of algae that released toxins as it decomposed, causing several areas of the recreational body of water to be declared unsafe for swimming.
Margaret Smigo and Doug Smith spoke Nov. 15 about the contaminants at the first Lake Anna Summit, sponsored by the Lake Anna Business Partnership and Lake Anna Winery, where the meeting was held. Approximately 30 residents attended, anxious to learn more about what has occurred and what future plans are being made for recurrences.
Smigo, waterborne hazards control program coordinator for the Virginia Department of Health, explained that algae on its own is beneficial. But when something in the environment changes, it frequently causes a rapid multiplication of cells, otherwise known as a “bloom.”
“Typically, the presence of a bloom is determined when the dissolved oxygen levels rise during the day and drop at night,” Smigo said. “Not all algae are harmful; it is species-dependent, and cyanobacteria, also known as ‘blue-green algae,’ can be one of those culprits.”
Changes in algae levels can be caused by an influx of nutrients, typically from runoff from the surrounding land, which may include fertilizers, animal wastes, temperature, and light availability.
Harmful algae bloom most frequently occurs in marine environments and can have a major impact on local economies, Smigo said. Fish and shellfish kills and recalls of infected fish and shellfish can dramatically affect businesses or areas that depends on them for its residents’ livelihoods. They can also threaten humans, the environment and animal habitats. While not all algae blooms are toxic, they can have other impacts on the environment such as damaging native grasses due to a lack of oxygen which then impacts fish habitats.
However, those that do produce toxins have an even larger impact, with exposure causing health issues to both humans and animals, particularly dogs. The three primary methods of toxin exposure include consumption, dermal and inhalation. Consumption occurs by ingesting water while swimming or participating in water sports and have the greatest impact on young children, the elderly and those with existing health issues where it causes intestinal or neurological system problems.
The toxins can also be aerosolized if water impacted by the bloom is used to water lawns or gardens, or can be aspirated into the lungs while swimming or from spray from a boat during water sports.
Harmful algae blooms were discovered during the Virginia Department of Environmental Quality’s normal water sampling in August. The DEQ performs sampling when a bloom is seen on the lake. This is the first year that the particular strains of cyanobacteria that produce toxins have occurred in such levels at Lake Anna, according to Smigo.
“Because Lake Anna is so large, the notification process following the identification had to be modified when issuing the “no swim” advisory, especially since there were several types of cyanobacteria discovered,” Smigo said. “Seven different varieties were discovered and we decided to use total counts [added all the harmful bacteria counts] when issuing the advisories.”
However, Smigo said getting the word out about the advisories became problematic since there are three jurisdictions involved and each is within a separate regional health department.
“If we have a harmful algae bloom in a small lake within one county, we notify the health department and can use signage that easily closes the area,” she said. “However, with the vast area we were dealing with and multiple jurisdictions, it became more difficult to get the word out about the concerns.”
Currently, the state health department uses educational signs and brochures and posts advisories on its website where residents can also report algae blooms. Those methods of notification need to be modified for Lake Anna, Smigo said, and her task force will examine ways to better notify citizens and visitors to the lake in subsequent outbreaks, which she said are likely to occur again.
This is a partial article. Read the full story in The Central Virginian’s Nov. 22, 2018 issue.
Click the F2F Banner for More Posts.