ABSTRACT

The whole research field of toxic cyanobacteria and associated hazard to human health is relatively new, with the first international meeting on the topic at Wright State University, Dayton, Ohio, in 1980 (Carmichael 1981). Since that time there have been very considerable developments in understanding of the organisms, toxins, health impacts, and processes for the removal of unwanted substances in the treatment of drinking water. A landmark development in public safety was the determination in 1998 by the World Health Organization (WHO) of a provisional Guideline Value for microcystin-LR in drinking water. This has been followed by individual national and regional governments adopting a regulatory standard for microcystins in drinking water, which has been closely related to the WHO guideline of 1.0 µg/L. The regulations have varied from the WHO guideline only by specifying toxicity equivalent to microcystinLR, thus including all microcystins, and through different population body weights and assumed proportion of the toxin in drinking water. In addition, New Zealand and Brazil have adopted Maximum Acceptable Values or Guideline Values for cylindrospermopsin of 3.0 and 15 µg/L, respectively, in drinking water.