Toxin-producing cyanobacteria in Lake Baikal and reservoirs of Baikal region (review)

Cyanobacteria containing toxin synthesis genes and capable to produce toxins have been found since 2005 in the plankton of the coastal zone of Lake Baikal and in the water bodies of the Baikal region. Analysis showed that the sequences for microcystin synthesis genes belonged to the genera Microcystis and Dolichospermum; the sequences for genes encoding paralytic shellfish toxins synthesis - to representatives of the genera cluster Anabaena/Dolichospermum/Aphanizomenon. Microcystin concentration in water exceeded the guideline for the drinking water quality in Lake Kotokelskoe and in the Ust-Ilimsk reservoir, as well as concentration of saxitoxin - in the Irkutsk reservoir and in the Kurkut bay of Lake Baikal. In 2015 the cyanotoxins were also recorded in Baikal benthic biofouling, the concentration varied in the range of 29.8-3050 mu g/kg dry weight (microcystins) and 21-29390 mu g/g dry weight (saxitoxin and its derivatives). Due to the absence of standards regulating concentration of the cyanotoxins produced by benthic cyanobacteria, it is impossible to estimate real health risks for humans. Situation in some places of Lake Baikal and water bodies needs the state control and management in the issue concerning toxic cyanobacteria.