When the bathing water profile defined in article D. 1332-20 indicates :
-a potential risk of proliferation of cyanobacteria, i.e. accumulation of cyanobacteria in the form of blooms, slicks or scum ;
or a tendency for macro-algae or marine phytoplankton to proliferate,
the person responsible for the bathing water ensures appropriate monitoring, determines whether their presence is acceptable for public health and identifies in good time the health risks and appropriate management measures that they require. It informs the Director General of the Regional Health Agency.
In the event of a proliferation of cyanobacteria, macro-algae or marine phytoplankton and when a health risk has been identified or is presumed, the person responsible for the bathing water immediately takes the appropriate management measures aimed in particular at preventing exposure of bathers and informs the public.