The Lake Anna Civic Association (LACA) submits these comments with significant concerns regarding the proposed removal of cell counts as a primary trigger for issuing Harmful Algal Bloom (HAB) advisories. While understanding the rationale for protocol modifications, we believe eliminating cell counts as a key determinant for public health advisories risks reducing the proactive and precautionary nature of the current protocol, potentially increasing public exposure to harmful cyanotoxins.

Cell counts, used with visual confirmation and cyanotoxin testing, offer a valuable early warning system for potential HAB risks. Removing this primary trigger could lead to a reactive approach, with advisories issued only after toxins exceed health thresholds. This delay could expose recreational users, especially vulnerable populations, to harmful conditions during early bloom stages when cell densities are substantial, even with low initial toxin levels.

Eliminating cell counts as a primary advisory trigger will diminish the perceived severity of HABs at Lake Anna, as documented by historical data. This could undermine future funding requests, as justifications often correlate elevated cyanobacteria biomass (cell counts) with potential cyanotoxin production and ecological/public health risks. Removing this direct indicator weakens the case for continued investment in mitigation strategies targeting nutrient loading from non-point sources in the Lake Anna watershed.

Furthermore, cell counts are a cost-effective and rapid indicator of potential HAB development, often preceding significant toxin increases. This early warning allows proactive communication and targeted management. Sole reliance on resource-intensive, reactive toxin testing may inadequately capture bloom dynamics and associated risks linked to high cell biomass, even with inconsistent toxin exceedances at sampling times.

We urge the Virginia Department of Health to reconsider removing cell counts as a primary advisory trigger. We recommend integrating cell counts as a crucial line of evidence alongside visual observations and cyanotoxin testing for a comprehensive, protective HAB advisory system. This integrated approach enables earlier public notification and preventative measures, ultimately better safeguarding public health and ensuring continued support for mitigation efforts.