ISO 11348 describes three methods for determining the inhibition of the luminescence emitted by the marine bacterium Vibrio fischeri (NRRL B-11177). This part of ISO 11348 specifies a method using freshly prepared bacteria. The method is applicable to waste water, aqueous extracts and leachates, fresh water (surface and ground water), sea and brackish water, eluates of sediment (fresh water, brackish and sea water), pore water, singles substances, diluted in water.