Overview
EN ISO 11348-2:2008 - "Water quality - Determination of the inhibitory effect of water samples on the light emission of Vibrio fischeri (Luminescent bacteria test) - Part 2: Method using liquid‑dried bacteria" is a standardized method for short-term ecotoxicity testing. The method uses a commercial liquid‑dried preparation of Vibrio fischeri (NRRL B‑11177) to measure how test waters or aqueous extracts inhibit bacterial bioluminescence. It applies to wastewater, leachates, surface and groundwater, seawater/brackish water, sediment eluates, pore water and single substances diluted in water.
Key Topics
- Test principle: Batch assay combining sample (or dilutions) with reconstituted liquid‑dried Vibrio fischeri and measuring luminescence after defined contact times (commonly 5, 15 or 30 minutes). Results are expressed as inhibition (LID) or ECx values (e.g., EC20, EC50) from a dilution series.
- Scope and sample types: Applicable to a broad range of aqueous matrices including eluates and pore water; guidance provided for high‑salinity and sediment‑derived samples.
- Reagents & sample handling: Use of analytical‑grade chemicals; sodium chloride diluent (20 g/L NaCl) is specified for osmotic support. Liquid‑dried bacteria must be stored frozen (≤ −18 °C) and reconstituted per supplier instructions - luminescence appears immediately after reconstitution.
- Interferences & corrections: Colour, turbidity, oxygen demand, pH outside ~6.0–8.5, and high salt/osmolarity can affect results. The standard describes approaches such as turbidity treatments, colour‑correction (double‑chamber tubes) and salt handling (Annex D) to reduce artefacts.
- Performance & reporting: Clauses cover procedure, evaluation, expression of results, validity criteria, precision data and required test report information.
Applications
- Routine environmental monitoring and compliance testing of effluents, surface waters and leachates.
- Ecotoxicity screening in wastewater treatment, landfill leachate assessment, sediment elutriate testing and risk assessment workflows.
- Research and R&D where rapid screening for toxic effects on marine luminescent bacteria is needed.
- Laboratories, environmental consultants, regulatory agencies and industry quality/control teams use this method as part of water‑quality and toxicity testing programs.
Related Standards
- ISO 11348-1: Method using freshly prepared bacteria
- ISO 11348-3: Method using freeze‑dried bacteria
- ISO 5667-16: Guidance on biotesting sampling
- ISO 5814: Dissolved oxygen (relevant for interpreting oxygen‑sensitive assays)
Keywords: EN ISO 11348-2:2008, Vibrio fischeri, luminescent bacteria test, water quality, toxicity testing, liquid-dried bacteria, EC50, ecotoxicology.
