Toxicology and risk assessment of freshwater cyanobacterial (blue-green algal) toxins in water.

The occurrence of cyanobacterial toxins affects aquatic organisms, terrestrial animals (both wild and domestic), and humans. Detrimental effects have been documented in the scientific literature during the past 50 years. Possible guideline values of some cyanobacterial toxins (microcystins, cylindrospermopsin, and anatoxin-a) are estimated, and they show that children and infants are more susceptible to cyanobacterial toxins than adults. Therefore, particular attention should be paid when cyanobacterial blooms occur, even at relatively low cell counts, to protect children and infants from possible risks. Based on these guideline values and the occurrence of the toxins, it can be concluded that chronic and subchronic exposure to cyanobacterial toxins does occur in some populations, particularly in developing countries where high proportions of the population consume untreated surface water directly, such as pond, ditch, river, or reservoir water. Because wildlife and domestic animals consume a large amount of untreated water daily, they are at higher risk than humans from cyanobacterial toxins. Calculated guideline values in Section X show that a relatively high risk posed by the toxins to these animals is likely to occur, even at low cell densities.