Determining the tolerance of green algae
to the toxicity of waste water

(DIN 38412-33)


Toxic effects of water constituents and waste water on the green algae Desmodesmus subspicatus are determined over a period of 72h.

Study design

The planktonic freshwater algae species Desmodesmus subspicatus is exposed to a dilution series of a waste water sample and incubated under defined light and temperature conditions for 72 h. Two replicates for each dilution, three negative control replicates and three positive control replicates with addition of a reference substance are studied in parallel. The cell density is measured at the beginning and at the end of the exposure period by fluorescence measurements. As test result, the lowest dilution D is reported at which an inhibition <20% is measured (=LID, lowest ineffective dilution).