Overview
ISO 10706:2000 specifies a laboratory method for determining the long‑term (chronic) sublethal toxicity of chemicals, industrial or sewage effluents and surface/ground waters to the freshwater crustacean Daphnia magna. Adapted from OECD Guideline 211, the standard describes a 21‑day exposure test that records parental survival and reproductive output (offspring per surviving parent) under controlled conditions to assess chronic water quality impacts.
Key topics and technical requirements
- Test organism & age: Daphnia magna females, less than 24 h old (2nd–5th brood), from healthy parthenogenetic cultures.
- Exposure duration: 21 days (semi‑static or flow‑through systems).
- Endpoints: parental survival and number of live offspring per live parent at test end; results compared to controls.
- Environmental conditions:
- Temperature: 18–22 °C, variability ≤ 2 °C.
- Photoperiod: 16 h light / 8 h dark; light intensity 600–800 lux (not > 1 200 lux).
- Dissolved oxygen: > 3 mg/L; pH 6–9 with ≤ 1.5 pH units change during the test.
- Hardness: ≥ 140 mg/L (as CaCO3) to support reproductive performance.
- Exposure solutions shall not be aerated.
- Dilution water: synthetic media (OECD M4/M7) or ASTM reconstituted hard freshwater (Annexes A & B). TOC recommendations and notes on EDTA use for metal testing are provided.
- Sample handling: sampling per ISO 5667‑2 and ISO 5667‑16. Ideal testing within 12 h; cool 0–4 °C and test within 24 h if delayed; freeze (< −18 °C) if >48 h, with frozen samples usable up to 2 months. Example volume guidance given for semi‑static tests.
- Preparation of test solutions: guidance on stock solutions, dispersants/solvents (if used, solvent in highest exposure ≤ 0.1 ml/L), ultrasonic dispersion for poorly soluble substances, and limits on stock additions.
- Quality & analysis: controls, selection of concentration series, renewal schedule (if semi‑static), feeding, observations, validity criteria and data analysis (including time‑weighted mean concentration, Annex D).
Applications and users
ISO 10706 is used for:
- Chronic ecotoxicity testing of chemicals and effluents
- Regulatory compliance and environmental risk assessment
- Effluent monitoring by wastewater utilities
- Chemical registration and safety dossiers
- Research in ecotoxicology and environmental monitoring
Typical users: environmental testing laboratories, regulators, ecotoxicologists, chemical manufacturers, wastewater treatment operators and environmental consultancies.
Related standards
- ISO 5667‑2 (Sampling techniques)
- ISO 5667‑16 (Guidance on biotesting of samples)
- OECD Guideline 211 (source guideline)
- ASTM reconstituted hard freshwater (referenced in Annex B)
Keywords: ISO 10706, Daphnia magna, long term toxicity, chronic toxicity test, water quality, effluent testing, dilution water, OECD 211.
