DDW Requests Cyanotoxin NLs

On February 4, 2021 the State Water Resources Control Board Division of Drinking Water (DDW) submitted the enclosed request ( DDW Request to OEHAA for Cyanotoxin NLs_2021-02-04 ) to the Office of Environmental Health Hazard Assessment (OEHHA) to develop recommendations for Notification Levels (NLs) for the following four cyanotoxins:

  1. Microcystins
  2. Cylindrospermopsin
  3. Anatoxin-a (“if information supports” development of an NL)
  4. Saxitoxins (“if information supports” development of an NL)

In 2015 EPA published 10-day Health Advisories (HAs) for microcystins and cylindrospermopsin.  The 10-day HA for microcystins for bottle fed infants (up to school age) is 0.3 µg/L.  The 10-day HA for adults is 1.6 µg/L.  The 10-day HA for cylindrospermopsin for bottle fed infants (up to school age) is 0.7 µg/L.  The 10-day HA for adults is 3 µg/L.

DDW requests that OEHHA review the EPA’s HAs for microcystins and cylindrospermopsin as part of this process.

Finally, the DDW letter cites recent World Health Organization (WHO) background documents for the four cyanotoxins (copies of the WHO documents are here: WHO Cylindrospermopsin Background WHO_Anatoxin-a Background_Dec 2020 WHO_Microcystins Background_Dec 2020 WHO_Saxitoxins Background  ).