Première évaluation du risque toxique lié aux cyanobactéries d'eau douce en France le programme « EFFLOCYA » First assessment of the toxical risk associated with fresh water cyanobacteria in France: the "EFFLOCYA" research program

SUMMARY An inquiry covering the whole French territory together with spécifie studies of natural and artificial réservoirs has been niadc to assess the human health risk related to the prolifération of toxin producing blue green algae (cyano­ bacteria). The conclusions show that any lentic ecosystem can be affected like it has been shown already in other countries ail over the world and more spe- cifically within the EU. The main genus concemed are: Microcystis, Plankto- thrix, Anabœna and Cylindrospermopsis. Blooms can occur juring the whole year since some species are well adapted to cold water and are not clearly linked with the trophic status of the aquatic ecosystem. The toxinic production is the largest when the cyanobacteria populations contain only a few number of species. The results of récent works are well correlated with our findings which show that the production of toxic hepta- peptides (microcystins) could be correlated with high levels of nitrate and depletions of ammonium and iron. The follow up of this work should now include the set up of a national obser- vatory of toxic algal blooms.