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 freeze-dried bacteria. This method is applicable to: — waste water; — aqueous extracts and leachates; — fresh water (surface and ground water); — sea and brackish water; — eluates of sediment (freshwater, brackish and sea water); — pore water; — single substances, diluted in water.