Overview
ISO 16191:2013 - "Water quality - Determination of the toxic effect of sediment on the growth behaviour of Myriophyllum aquaticum" - specifies a laboratory contact test to measure the toxic effects of natural freshwater and artificial sediments on the macrophyte Myriophyllum aquaticum (parrot feather). The method quantifies phytotoxicity within a 10-day exposure by comparing plant growth (fresh mass) in test sediments against a defined control (artificial sediment), allowing calculation of growth inhibition and ECx (effective concentration) values. The procedure addresses both dissolved and particle‑bound contaminants in sediment.
Key topics and technical requirements
- Test organism and format
- Uses emersed growth of Myriophyllum aquaticum whorls (apical parts), typically three whorls per replicate vessel.
- Pre-culturing and acclimatization steps required before testing.
- Exposure conditions
- 10-day contact test comparing test samples to control sediment.
- Measurement of growth as fresh mass; calculation of growth rate (r) and inhibition (I).
- Replication and validity criteria specified to ensure reliable results.
- Control and artificial sediment
- Composition of artificial control sediment (dry mass): peat powder 5%, quartz sand 74%, kaolin clay 20%, CaCO3 1%.
- Preparation steps for peat suspension, blending, pH stabilization (target ~7.0 ± 0.5).
- Reagents and media
- Use of Steinberg nutrient medium (Annex B) and specified reagents (e.g., kaolin, quartz sand, peat).
- Recommended reference substance: 3,5‑dichlorophenol for performance checks.
- Data evaluation
- Defined calculations for growth rate, mean values across replicates, percent inhibition, and estimation of ECr_x values.
- Reporting requirements and validity criteria included.
- Safety and interferences
- Laboratory containment to prevent escape of live plant material.
- Guidance on potential interferences (e.g., contaminated kaolin or unsuitable peat).
Applications and users
ISO 16191:2013 is practical for:
- Environmental and ecotoxicology laboratories performing sediment toxicity testing.
- Regulatory agencies and consultants assessing dredged material, contaminated sediments, or remediation success.
- Research groups studying macrophyte responses to pollutants and sediment-bound contaminants.
- Wastewater and sediment-monitoring programs requiring standardized biological endpoints (growth inhibition, ECx).
Benefits include a standardized, reproducible measure of sediment phytotoxicity that captures both dissolved and particle‑bound effects using a macrophyte relevant to many aquatic systems.
Related standards
- ISO 5667-15, ISO 5667-16 (sampling and handling of sediments/biotesting)
- ISO 11465 (soil dry matter determination)
- ISO 20079 (duckweed growth inhibition - comparable plant test)
- OECD 218 (sediment-water chironomid test)
Keywords: ISO 16191:2013, Myriophyllum aquaticum, sediment toxicity, water quality, sediment contact test, growth inhibition, artificial sediment, ecotoxicology.
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