[Study on guideline of alga in source water]

Toxic bloom in the sources of drinkable water has been a public health problem. Hindered by the complicated analysis procedure, very limited efforts has been done in investigating toxin level. Patronized by the Chinese Academy of Preventive Medicine, a study on alga hygiene criteria of drinkable water sources in China was conducted. Available literature was reviewed and ecological research and toxicological tests were carried out. The criteria on alga biomass in drinkable water source was formulated by referring the criteria of microcystin--LR in drinking water recommended by WHO and Ministry of Health, China. Three kinds of criteria were worked out: primary criteria, which is to ensure safety, is 1.0 x 10(4) per liter, secondary criteria, which should be alert, is 2.1 x 10(5) per liter, and third--rate criteria, which might be toxic, is 1.2 x 10(6) per liter. It is suggested that these criteria are valuable and feasible in routine work.