Overview
EN ISO 11348-1:2008 (ISO 11348-1:2007) specifies a standardized luminescent bacteria test using freshly prepared cultures of the marine bacterium Vibrio fischeri (NRRL B‑11177) to determine the inhibitory effect of water samples on bacterial light emission. The method is designed for routine water quality and ecotoxicity screening across a wide range of aqueous matrices including wastewater, surface and groundwater, sea/brackish water, leachates, sediment eluates and pore water, as well as single substances diluted in water.
Key topics and technical requirements
- Test principle: Batch exposure of freshly prepared V. fischeri suspensions to test samples; inhibition is quantified by reduction in bioluminescence after defined contact times (typically 15 min and 30 min; 5 min optional).
- Endpoints: Inhibition expressed as LID (luminescence inhibition degree) and/or effective concentrations (e.g., EC20 / EC50) derived from a dilution series.
- Test organism: Freshly cultured Vibrio fischeri NRRL B‑11177 prepared from cultures or commercial preparations; labs must use trained personnel and follow laboratory safety practice.
- Reagents & diluent: Use analytical-grade chemicals and purified water; a sodium chloride solution is specified as diluent for osmotic control in the test.
- Interferences and corrections:
- Colour and turbidity can reduce measured luminescence; the standard provides colour-correction options (e.g., double-chambered absorption correction - Annex A).
- Oxygen demand and low dissolved oxygen can artifactually reduce bioluminescence.
- pH sensitivity: samples outside pH 6.0–8.5 may affect results and may require adjustment.
- Salt effects: testing salt-water samples may stimulate luminescence or cause hyperosmotic effects if combined salt levels exceed ~35 g/L osmolarity; guidance is in Annex D.
- Quality criteria: Includes control correction factor, validity checks, and precision/replicate requirements.
Practical applications and users
- Environmental and water testing laboratories conducting toxicity screening for:
- Municipal and industrial wastewater compliance monitoring
- Assessment of leachates, eluates, and pore water from landfills, soils and sediments
- Freshwater and marine ecotoxicology studies and rapid screening of single chemicals
- Regulatory agencies, consultants and research institutions use ISO 11348-1 for rapid, cost-effective bioassays to flag toxic samples prior to more detailed testing.
Related standards
- ISO 11348-2 (liquid-dried bacteria) and ISO 11348-3 (freeze-dried bacteria) - alternative preparation methods
- ISO 5667-16 (sampling guidance for biotesting)
- ISO 7027 (turbidity) and ISO 5814 (dissolved oxygen) - supporting measurements referenced by the method
This standard is essential when implementing reliable, standardized luminescent-bacteria toxicity testing as part of a water quality monitoring or ecotoxicity assessment program.
