Overview
EN ISO 10253:2024 - Water quality - Marine algal growth inhibition test with Skeletonema sp. and Phaeodactylum tricornutum - is a CEN-adopted International Standard that specifies a laboratory method for determining inhibition of growth of two unicellular marine algae by substances or mixtures in sea water and by environmental water samples (effluents, elutriates). This fourth edition (2024) supersedes the previous edition and provides updated procedures for marine algal toxicity testing applicable to readily water‑soluble substances and to environmental monitoring.
Key topics and technical requirements
- Test organisms: Skeletonema sp. and Phaeodactylum tricornutum are used as standard marine test species.
- Test media and reagents: Preparation of synthetic sea water and nutrient stock solutions, pH control, and use of appropriate water quality reagents.
- Test procedure: Steps include preparation of growth medium, pre‑culture and inoculum, selection of test concentrations, preparation of stock solutions, incubation and measurement of algal growth.
- Measurements and endpoints: Cell density, specific growth rate (μ - proportional rate of increase in cell density per day) and percentage inhibition are calculated; results are used to determine effect concentrations (e.g., EC values).
- Validity criteria and data interpretation: Requirements for control growth, statistical plotting of growth curves, calculation of % inhibition and determination of effect concentrations (EC(r)).
- Annexes and options: Informative annexes cover dilution of mixtures (A), procedures using stored inocula and spectrophotometric cells (B), performance data (C), and a 24‑well microwell plate method for Phaeodactylum tricornutum (D).
- Scope limitations: Intended for substances that remain in the test medium (not significantly degraded or eliminated). For poorly soluble, volatile, metal compounds, effluents and sediments, modifications are referenced (ISO 14442, ISO 5667‑16).
Applications and users
This standard is essential for:
- Environmental testing laboratories conducting marine algal growth inhibition tests and algal toxicity testing.
- Regulatory authorities assessing chemical or effluent impacts on marine primary producers.
- Chemical manufacturers and registrants performing ecotoxicity testing for product safety and compliance.
- Researchers and ecotoxicologists studying effects of pollutants on coastal and marine phytoplankton.
Practical applications include screening of wastewater effluents, assessing ecological risk of new chemicals, and providing standardized data for environmental impact assessments.
Related standards
- ISO 14442 - Guidelines for algal tests with poorly soluble materials, volatile compounds, metals and waste water.
- ISO 5667‑16 - Sampling - Guidance on biotesting of samples.
- EN ISO 10253:2024 aligns with CEN adoption and national implementation requirements across member bodies.
Keywords: EN ISO 10253:2024, marine algal growth inhibition test, Skeletonema sp., Phaeodactylum tricornutum, water quality, algal toxicity testing, effluents, elutriates, specific growth rate, EC value.
