Overview
EN ISO 20963:2011 (ISO 20963:2005) is a soil quality standard that specifies a laboratory method to determine the acute toxicity of contaminated soils and test substances to larvae of Oxythyrea funesta. The method exposes third‑instar larvae to pollutants via both cuticular and alimentary uptake and quantifies mortality after a 10‑day exposure to derive metrics such as LC50. The procedure can use either field test soils (with appropriate controls and dilution series) or a defined artificial soil substrate for testing pure substances.
Key topics and requirements
- Test organism: Oxythyrea funesta larvae (third instar), recommended fresh mass 100–200 mg; larvae in a single container should not differ by more than 50 mg.
- Exposure and endpoints: Acute mortality after 10 days is the primary endpoint; optional measurement of larval growth (mass increase) may supplement results.
- Test design: Two‑step approach - preliminary range‑finding test followed by definitive test that produces effects between ~10 % and 90 % mortality for LCx determination.
- Substrates: For contaminated soils, use either an uncontaminated soil comparable to the sample or an artificial soil (composition in accordance with ISO 11268‑1; peat and kaolinite specified). Mass per test container ≈ 300 g (dry mass).
- Environmental conditions: Tests performed at (26 ± 1) °C in complete darkness.
- Exclusions and limitations: Not applicable to volatile substances (Henry’s constant or air/water partition coefficient > 1, or vapour pressure > 0.00133 Pa at 25 °C). The method does not account for degradation of test substances during the exposure period.
- Result expression: Determination of LC50, LCx, LOEC and NOEC relative to controls.
Practical applications and users
This standard is used by laboratories and professionals involved in soil ecotoxicology, contaminated land assessment and regulatory compliance:
- Environmental testing laboratories conducting toxicity assays on contaminated soils or chemicals.
- Ecotoxicologists and researchers evaluating pollutant effects on soil invertebrates and ecosystem health.
- Remediation consultants and site managers assessing soil toxicity and establishing clean‑up priorities.
- Chemical and agrochemical manufacturers performing hazard assessment and generating data for registration.
- Regulators and risk assessors using standardized endpoints (LC50, LOEC, NOEC) for decision making.
Benefits include repeatable, comparable acute toxicity data for soil quality monitoring, risk assessment and product/chemical evaluation.
Related standards
- ISO 11268‑1 - Soil quality - Effects of pollutants on earthworms (artificial soil substrate)
- ISO 10381‑6 - Soil sampling guidance for biological testing
- ISO 10390 - Soil pH determination
- ISO 11269‑2 - Effects of chemicals on higher plants (related plant emergence/growth test)
Keywords: soil quality standard, acute toxicity test, Oxythyrea funesta, soil ecotoxicology, LC50, artificial soil substrate, contaminated soil assessment.