California Guidelines for Cyanobacteria in Recreational Inland Waters - Voluntary
Help is out there for local health agencies, lake managers, park rangers, and the public.
The California Cyanobacterial and Harmful Algal Bloom Network (CCHAB) provides this guidance to assist environmental and public health managers in responding to inland harmful algal blooms (HABs). Inland HABs include blooms occurring in freshwater and estuarine environments. The primary audience for the guidance are public health officials, environmental health officials, resource managers, and other interested persons who require a streamlined approach to address the risks posed by HABs as well as templates for advisory signs.
Participating agencies - State Water Resources Control Board, Office of Environmental Health Hazard and Assessment (OEHHA), and California Department of Public Health (CDPH) - have developed this and are further refining guidelines for addressing human and animal health concerns for cyanobacteria HABs in recreational waters.
Note: This guidance does not address cyanotoxins in drinking water, resources for addressing cyanotoxins in drinking water are found here. This guidance is informational only and does not represent policy or regulation.
- 2018 Guidance Document: Under development, for questions please contact the Guidance Update Subcommittee by email at email@example.com.
- 2016 Guidance Document Updates (to supplement the 2008 version listed below):
- Decision tree & narrative for posting and de-posting advisory signs
- Trigger levels for protection of human and animal health
- Appendix A - Description of cyanotoxin trigger levels in recreational water bodies
- Reporting of Blooms
- Advisory Signs
- Outreach and Communication
- 2008 Blue-Green Algae Draft Voluntary Guidance Document, prepared by CCHAB Network
The decision tree was developed to guide users through necessary steps to post and/or de-post advisory signs. To download the decision tree and narrative, click here (PDF).
Table 1 below provides recommendations to post advisory signs based on trigger levels for the following criteria: concentrations of three major cyanotoxins in water, cell count of potential toxin producers, and site specific indicators. These trigger levels were developed to protect human and animal (dogs, livestock) health from cyanobacteria HABs; for more information on how these levels were derived refer to Appendix A - Description of cyanotoxin trigger levels in recreational water bodies. The advisory signs communicate potential risk to the public.
Trigger Levels Download (PDF)
|Table 1: Trigger Levels For Human and Animal Health|
|Total Microcystins b||0.8 µg/L||6 µg/L||20 µg/L|
|Anatoxin-a||Detection c||20 µg/L||90 µg/L|
|Cylindrospermopsin||1 µg/L||4 µg/L||17 µg/L|
|Cell Density (Toxin Producers)||4,000 cells/mL||--||--|
|Site Specific Indicators of CyanoHAB||Visible bloom/discoloration, scum, algal mats, satellite imagery.||--||--|
- The primary triggers are met when ANY toxin exceeds criteria
- Microcystins refers to the sum of all measured microcystin congeners
- Must use an analytical method that detects ≤ 1 µg/L Anatoxin-a
When a bloom is occurring, it is critical that there is understanding of the cyanobacteria and cyanotoxins present and communication of the potential risk to protect human and animal health. Blooms of cyanobacteria and algae, as well as animal or human illnesses associated with exposure to HAB toxins, are recommended to be immediately reported to the California HAB Hotline. The HAB Hotline is a central reporting hub that is managed by the State Water Resources Control Board (State Water Board) and the information collected by the hotlines is used to maintain a interactive map of current harmful algal bloom reports and advisories on the California HABs Portal.
Reports of potential HAB occurrences and any related illnesses can be reported to the HAB Hotline by using any of the following:
- Online Freshwater Bloom Incident Form,
- phone: 1 (844) 729-6466 (toll free), or
English and Spanish versions of advisory signs are provided for download.
- The PDF downloads provide pre-made signs and space to insert local agency contact information; it is recommended to laminate paper signs or use professional sign printing services.
- The PowerPoint downloads allow customization of signs by deleting individual icon/text message components that are not appropriate for a specific water body. However, text with each component cannot be changed. Components can be moved to allow more space for local agency contact information (text box at the bottom of each sign). Signs Version 8/5/2016
Supplemental Information – sign and icons (PowerPoint format)
Aside from the placement of advisory signs, other forms of public information and education may be appropriate, including factsheets, press releases, local information on county websites, public service announcements, or social media messages.
Doctors and veterinarians may not be familiar with the symptoms of cyanotoxin exposure in humans, pets, and livestock. Symptoms of cyanotoxin poisoning may be misdiagnosed without proper information on their acute and chronic effects. Facts sheets should be provided to local doctors, hospitals, clinics and veterinarians with information about the occurrence and symptoms of cyanotoxin exposure. In addition, downstream users of the impacted waterbody should be informed since cyanotoxins can be transported downstream; cyanotoxin transport of 20+ miles have been documented.
Outreach resources are available on California HABs Portal.
- For the general public:
- Frequently Asked Questions (FAQs) about Freshwater and Estuarine Harmful Algal Blooms
- Frequently Asked Questions (FAQs) for Human Health
- Frequently Asked Questions (FAQs) for Dogs
- Frequently Asked Questions (FAQs) for Livestock and other Large Animals
- Frequently Asked Questions (FAQs) for Fish
- Frequently Asked Questions (FAQs) for Wildlife (Wild Birds and Mammals)
- For medical professionals
- For veterinarians