Harmful Algal Blooms (HABs) – Division of Water Monitoring and Standards
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Recreational Advisory Guidance Levels
(Details can be found in the Cyanobacterial Harmful Algal Bloom (HABs) Freshwater Recreational Response Strategy Appendix E)
In response to Governor Murphy’s HAB initiative, the DEP has developed a color-coded alert index with signage that provides much greater precision on recreational use recommendations for impacted water bodies based on levels of cyanobacteria and/or cyanotoxins present. The index has multiple alert categories, each providing recommendations of activities that should not be pursued based on water monitoring results.
The following are NJ’s Health Advisory Guidance levels.
Toxins:
- Microcystins – 2 µg/L
- Cylindrospermopsin – 5 µg/L
- Anatoxin-a – 15 µg/L
- Saxitoxin – 0.6 µg/L
Suggested Advisory Language
- Advisories below may be used by government and non-government entities to alert the public for risk.
- Advisory language is based on the NJ Health Advisory Guidance levels.
- Intended to be protective for a range of exposures that are most likely to occur
- When posting advisories, it is recommended to err on the side of caution to avoid unnecessary risk to the public.
- If necessary, it is suggested that the language be tailored to the specific HAB occurrence and waterbody use.
* HABs previously confirmed at a waterbody during the recreational season may persist or reoccur during the winter and caution should be taken. If you see a suspected HAB, avoid it and report it.
| HAB Alert Levels | Criteria | Recommendation |
|---|---|---|
| HAB Not Present | HAB reported and investigated. No HAB present. | None |
| WATCH Suspected or confirmed HAB with potential for allergenic and irritative health effects |
Suspected HAB based on field survey OR Confirmed cell counts ≥20k – ≤80k cells/mL AND No known toxins above public health thresholds |
Public Bathing Beaches Open Waterbody Accessible: Use caution during primary contact (e.g. swimming) and secondary (e.g. non-contact boating) activities Do not ingest water (people/pets/livestock) Do not consume fish An Alert is initiated at beaches if cell counts are 40K to < 80K. An Alert begins actions to monitor the beach more frequently due to increasing potential for toxin production and to ensure the HAB has not elevated to a higher risk Tier. |
| ADVISORY Confirmed HAB with moderate risk of adverse health effects and increased potential for toxins above public health thresholds |
Lab testing for toxins Microcystins: ≥2 μg/L Cylindrospermopsin: ≥5 μg/L Anatoxin-a ≥15 μg/L Saxitoxin-a ≥0.6 μg/L OR Confirmed cell counts ≥80k ug/L |
Public Bathing Beaches Closed Waterbody Remains Accessible: Avoid primary contact recreation Use caution for secondary contact recreation Do not ingest water (people/pets/livestock) Do not consume fish |
| WARNING Confirmed HAB with high risk of adverse health effects due to high toxin levels |
Toxin (microcystin) ≥20 – ≤2000 μg/L |
Public Bathing Beaches Closed Cautions as above May recommend against secondary contact recreation |
| DANGER Confirmed HAB with very high risk of adverse health effects due to very high toxin levels |
Toxin (microcystin) ≥2000 μg/L |
Public Bathing Beaches Closed Cautions as above. Possible closure of all or portions of waterbody and possible restrictions of access to the shoreline. |