Bloom-forming cyanobacteria have been observed in
waterbodies including drinking water reservoirs all over the world.
Several strains of these microorganisms have the ability to produce
potent toxins as secondary metabolites, the so-called cyanotoxins.
These have caused many animal deaths and have also been
implicated in cases of human illness, e.g. in U.S.A., Australia,
China, Brasil, and Great Britain. According to their effects on
health, cyanotoxins are divided into hepatotoxins (liver
damaging, tumor promoting; microcystins, nodularins, cylindrospermopsins),
neurotoxins (nerve damaging; anatoxin-a, saxitoxins), and dermatotoxins
dermatitis; aplysiatoxins, lyngbyatoxins).
Since cyanotoxins have been found in drinking waters, a Guideline
Value of 1.0 µg/L for microcystin-LR in drinking water is proposed by
the World Health Organisation (WHO). In Europe, these biotoxins are
not yet clearly regulated. However, the European Water Framework
Directive (2000/60/EC) characterises high priority water
pollutants. Toxin producing cyanobacteria have been specifically
highlighted as a potential key hazardous pollutants.
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