The World Health Organization recently released the second edition of Toxic cyanobacteria in water, which was edited by Ingrid Chorus and Matin Welker, M. This book has been a go-to-resource for people throughout the world on toxic cyanobacteria science, risks and management. This presentation focused on the new guideline cyan-toxin values and their relevance for human health.
New W.H.O Cyanotoxin Guideline Values and Guidance for Assessing Risks of Occurrence at Concentrations Relevant for Human Health – an online presentation on March 23, 2021 presentation given by Ingrid Chorus of the Department Head for Drinking-Water and Swimming-Pool Hygiene at the German Environment Agency.
Investigations around the world are screening for the occurrence of toxic cyanobacteria, and such programmes are increasingly including not only microcystins but also cylindrospermopsins as well as anatoxins and saxitoxins. The experience in Toledo in 2014, where microcystin concentrations in drinking water briefly exceeded the World Health Organisation (WHO) guideline value (GV) of 1 µg/L with up to 2.5 µg/L highlighted a need for guidance on concentrations that can be tolerated for short periods while mitigation measures are being implemented. In response to this demand, WHO has now derived short-term drinking water GVs for all 4 groups of cyanotoxins as well as values for recreational exposure and a lifetime GV also for cylindrospermopsins in drinking water. WHO further emphasises the need to address cyanotoxin occurrence comprehensively, with risk assessment and management from catchment to consumer, preferably in the context of developing a Water Safety Plan (WSP). This is important in order to prioritise hazards according to the risk they cause and thus be most effective in protecting public health. This need is being increasingly recognised, and more countries are incorporating risk-based approaches in their regulations to complement “end-of-pipe” monitoring, even in Europe, where regulatory culture has traditionally focused on meeting standards rather than acknowledging that risk cannot be completely avoided. An example of this progress is the newly revised EU Drinking Water Directive (EU DWD). The presentation will explain the derivation of the new cyanotoxin GVs, outline the application of the WSP-approach to cyanotoxins and introduce the new, totally revised edition of “Toxic Cyanobacteria in Water” which supports incorporation of cyanotoxins when developing a WSP.