ISO 11348-1:2007

Overview

ISO 11348-1:2007 - Water quality - Determination of the inhibitory effect of water samples on the light emission of Vibrio fischeri (Luminescent bacteria test) - Part 1: Method using freshly prepared bacteria describes a standardized bioassay to measure acute toxicity of water samples using freshly cultured marine bioluminescent bacteria (Vibrio fischeri, NRRL B‑11177). The test quantifies inhibition of bacterial light emission after controlled exposure and is applicable to wastewater, surface and groundwater, sea and brackish water, sediment eluates, pore water, leachates and single substances diluted in water.

Key topics and technical requirements

• Test organism: Vibrio fischeri (NRRL B‑11177) prepared fresh from culture rather than freeze‑ or liquid‑dried cells.
• Principle: Batch test mixing bacteria suspension with sample; measure luminescence after defined contact times (optionally 5 min, routinely 15 min and 30 min) and calculate inhibition metrics such as LID and EC20 / EC50 from a dilution series.
• Controlled conditions: Typical measurement temperature is 15 °C ± 1 °C; luminometer and thermo‑blocks specified to reduce variability.
• Reagents & media: Uses a defined bacterial suspension medium and a sodium chloride diluent (20 g/L NaCl); protective and culture media are specified for preparing fresh bacteria.
• Quality checks & corrections: Includes sample oxygen requirement (> 3 mg/L), pH considerations (recommended pH 6.0–8.5 or adjustment when required), and corrections for colour/turbidity (annex A). A correction factor compensates for control intensity changes during exposure.
• Interferences: Notes potential bias from colour, turbidity, high oxygen demand, nutrient effects, and high salt/osmolarity; guidance provided for salt water testing (Annex D) and dilution-series preparation (Annex B).
• Performance & reporting: Criteria of validity, precision data and recommended reporting elements are defined.

Applications and who uses it

• Environmental testing laboratories use ISO 11348-1 for regulatory compliance, effluent monitoring and environmental risk assessment.
• Wastewater treatment plants and industrial dischargers apply the method to screen toxicity of effluents, leachates and process waters.
• Contract testing and research labs use it for ecotoxicity screening of single substances and mixtures.
• Regulators and consultants incorporate results (EC50/LID) into permitting, impact assessments and remediation planning.

Related standards

• ISO 11348-2 and ISO 11348-3 (same luminescent bacteria test using liquid‑dried and freeze‑dried bacteria).
• ISO 5667-16 (sampling guidance for biotesting), ISO 5814 (dissolved oxygen measurement), ISO 7027 (turbidity).

Keywords: ISO 11348-1:2007, Vibrio fischeri, luminescent bacteria test, water quality, toxicity testing, EC50, LID, freshly prepared bacteria, wastewater, sediment eluates.