Thank you for submitting your comments regarding the Virginia Department of Health (VDH) guidance document posted to the Virginia Town Hall entitled Guidance for Cyanobacteria Bloom Recreational Advisory Management.  The public comment period ended on May 21, 2025. VDH has reviewed all of the comments submitted on the Virginia Town Hall Including comments submitted in emails to VDH staff. 

Under the new proposed guidance, VDH will now issue a recreational advisory when toxin concentrations are exceeded and will no longer be using cell counts to issue advisories for harmful algal blooms (HAB).   This decision is based on an extensive data review, review of other state protocols and is consistent with the Environmental Protection Agency’s (EPA) Recommended Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermposin found here.  

The change in approach is also supported by the existing data collected in Virginia inland waterways from 2020-2024 which show that elevated cell densities do not indicate there is an unsafe level of toxin. The guidance change will result in more efficient investigations by the Virginia Department of Environmental Quality (DEQ) and VDH, with results received from the Department of General Services Division of Consolidated Lab Services (DCLS) in a timelier manner. The change should also reduce the uncertainty in public health messaging and advisories. The public will know if toxins are present in waters, and advisories will be issued when toxins exceed VDH and EPA safe swimming thresholds. Overall, toxin testing provides a more reliable and direct assessment of the risks associated with HABs.   

It is important to note that this guidance change will not reduce or limit the response to HAB reports. VDH will continue to collect and consider all potential HAB reports.  DEQ will continue to focus monitoring efforts in areas with high recreation and known blooms, will investigate potential algal blooms more extensively, and will collect more samples during each investigation.   Increased sampling will result in more comprehensive investigations, with sampling both in areas that are representative of larger water body segments and in areas where blooms are densest and where toxins may exist. 

Although advisories will be based on toxins only, VDH will consider any type of information about a potential HAB and may use it to alert the public that a bloom might be present, or to help communities develop such alerts for their waterways. Even if a HAB has not been confirmed, if water is discolored, murky, has an odor or appears to have a film on the surface, humans and pets should stay out of the water.