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;