Harmful algal blooms (HABs) in freshwater ecosystems consist of accumulations of cyanobacteria that can pose adverse health effects to humans either through direct contact with the cells or through the toxins they can produce. Often, humans are exposed to these conditions when they are recreating, primarily through full body contact, in waters of the state. In Utah, the local health departments (LHDs) have the authority to post health advisories and close waterbodies.
The Utah Division of Water Quality (DWQ) and Utah Department of Health (DOH) provide supporting roles to the LHDs. DWQ devises and executes sampling plans that prioritize waters that are at-risk for cyanobacteria blooms (eutrophic waters) and highest risk for human exposure (State Park beaches, drinking water sources). DWQ interprets results, and with the support of DOH, assists LHDs with recreational advisory decision-making.
In 2017, the Environmental Protection Agency (EPA) developed draft recreational health guidance for cyanobacteria exposure. This guidance was limited to providing recreational health thresholds for two cyanotoxins: microcystin and cylindrospermopsin. The EPA provided additional guidance on adverse health effects for cyanobacteria cell counts. Utah adopted these values into our guidance from 2017 through 2019. Recently, EPA finalized their guidance as Clean Water Act 304(a) human health criteria, and now, Utah is incorporating these updated thresholds into our guidance.
Open the Utah HAB Guidance Summary PDF to access the updated guidance thresholds or to provide public comment.
Public comment must be received within 30 days of January 22, 2020. Please refer questions and comments to Kate Fickas of Utah Division of Water Quality.