Overview
ISO 16778:2015 specifies an early‑life stage toxicity test using the calanoid copepod Acartia tonsa to assess the effects of a chemical substance, effluent, or environmental water sample on cold‑water marine and brackish populations. The semi‑static exposure starts with eggs and continues until emergence of juvenile (copepodite) stages (total test duration ~5–6 days). Measured biological endpoints are survival and larval development ratio (LDR), with results reported as NOEC/LOEC or effect concentrations (ECx).
Key topics and technical requirements
- Test species and life stages: Use eggs from healthy Acartia tonsa cultures; culturing guidance is provided (Annex G).
- Exposure conditions: Semi‑static exposures from egg to juvenile; typical duration 5–6 days when ~60% of control animals have reached copepodite stage.
- Endpoints and metrics:
- Larval Development Ratio (LDR) - fraction of animals reaching copepodite stage vs total surviving nauplii + copepodites.
- Survival, hatching success, mortality.
- Outcome expressed as NOEC, LOEC, or ECx (e.g., EC50).
- Test media and water quality:
- Use filtered natural seawater or reconstituted salt water (Annex A).
- Dilution water: dissolved oxygen >70% air saturation, pH 8.0 ± 0.3; recommended culturing conditions include 20 ± 1 °C and salinity ~20 ± 2 ‰ (acclimation guidance provided).
- Apparatus and monitoring:
- Glass or chemically inert vessels, stereomicroscope for stage scoring, oxygen/pH/salinity/temperature monitoring.
- Filtration, aeration, controlled lighting and feeding (per test guidance and Annex B).
- Quality assurance:
- Measurement of test substance concentrations and physical‑chemical parameters.
- Validity criteria, data collection sheets, and calculation methods included (Annexes C–F).
Applications and users
ISO 16778:2015 is used by:
- Environmental and ecotoxicology laboratories performing marine and brackish water toxicity testing.
- Regulatory agencies assessing chemical, effluent and water quality impacts on planktonic food webs.
- Researchers studying sublethal developmental effects on copepods and trophic‑transfer implications.
- Aquaculture and hatchery facilities assessing safety of water sources and feed organisms.
Practical applications include regulatory compliance testing, site‑specific effluent impact assessment, hazard classification, and research into developmental toxicity affecting fish prey availability.
Related standards
- Developed by ISO/TC 147 (Water quality), Subcommittee SC 5 (Biological methods).
- Definitions reference ISO/TS 20281.
- Complementary aquatic toxicity standards (other ISO and national/international test guidelines) can be used alongside ISO 16778 for broader environmental risk assessment.
Keywords: ISO 16778:2015, Acartia tonsa, calanoid copepod, early‑life stage test, LDR, water quality, copepod toxicity test, NOEC, EC50, marine ecotoxicology.