OEHHA Recommended Cyanotoxin NLs

OEHHA Recommended NLs for Cyanotoxins

On February 4, 2021 the State Water Resources Control Board (SWRCB) Division of Drinking Water (DDW) submitted a written request to the California Office of Environmental Health Hazard Assessment (OEHHA) to develop recommended Notification Levels (NLs) for four cyanotoxins (copy of the February 4, 2021 DDW memo is here DDW Request to OEHAA for Cyanotoxin NLs_2021-02-04).

In response to that request, on May 3, 2021 OEHHA submitted the following recommended NLs to the SWRCB:

Anatoxin-a – Recommended NL 4 µg/L

Saxitoxins – Recommended Interim NL: 0.6 µg/L

Microcystins – Recommended Interim NL 0.03 µg/L

Cylindrospermopsin – Recommended Interim NL: 0.3 µg/L

Two memos from OEHHA to the SWRCB providing background and how the NLs were calculated are here (OEHHA NL_Anatoxin_2021-05-03 OEHHA_Interim NLs_Three Cyanotoxins_2021-05-03 ).

For three of the cyanotoxins, OEHHA recommended that the NLs be used on an interim basis “…while it completes its review of the sizeable database of recent toxicity studies on these cyanotoxins and derives final recommendations.”

Link to OEHHA announcement;


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About Dan Askenaizer

Dr. Askenaizer leads WQTS’ work on regulatory compliance support for many of our water agencies clients. Dr. Askenaizer tracks water quality and treatment regulations at the Federal and State levels and provides regulatory updates to our clients. Dr. Askenaizer has strong expertise in the development of Regulatory Monitoring and Compliance Plans (RMCPs), which he has completed for a number of water agencies. He has also been working on a number of projects dealing with the development of distribution system monitoring plans and review of nitrification control strategies. Prior to joining WQTS, Dr. Askenaizer was the Water Quality Manager for the Glendale Water and Power. Under his leadership, the Water Quality Group conducted a demonstration-scale study of chlorite for nitrification control and a pilot-scale study of biological treatment for removal of nitrate. Dan has 30 years of experience working on projects dealing with regulatory, water quality and public health issues. Dan has given numerous presentations at workshops and round-tables across the country for water utilities. Dan was instrumental in developing and implementing a Mentoring Program for water staff and was involved in a Sustainable Development team.