EN ISO 21285:2020

Overview - What EN ISO 21285:2020 covers

EN ISO 21285:2020 (ISO 21285:2019) is a standardized chronic ecotoxicology test for assessing soil quality by measuring the inhibition of reproduction of the predatory soil mite Hypoaspis aculeifer caused by soil contaminants. The method quantifies reproduction (number of juveniles) after exposure - primarily via alimentary uptake - and reflects the bioavailability of contaminant mixtures in natural or amended soils under temperate conditions.

Key technical topics and requirements

• Test organism: Hypoaspis aculeifer (soil predatory mite; arachnid).
• Measured endpoint: Reproduction expressed as number of juveniles.
• Test substrates: Natural contaminated soils, reference soils or a defined artificial (standard) soil; dilution series may be used for contaminated-site testing.
• Exposure route: Mainly alimentary uptake; method characterizes habitat function of soils.
• Applicability: Contaminated sites, amended soils, remediated soils, industrial/agricultural sites, and waste materials (dredged material, municipal sludge, compost, manure) intended for land disposal.
• Limitations:
  • Not applicable for substances with air/soil partition coefficient > 1.
  • Not applicable for substances with vapour pressure > 300 Pa at 25 °C.
  • Test method does not monitor persistence/stability of test substances over time.
• Design elements: Range-finding, definitive and limit tests; controls and dilution controls; feeding and counting procedures; validity checks and statistical analysis as part of result interpretation.
• Stand-alone role: Complements other soil test standards - does not replace earthworm (ISO 11268-2) or collembolan (ISO 11267) reproduction tests because it targets a different trophic/taxonomic group.

Applications - Who uses this standard and why

• Environmental testing laboratories conducting bioassays for contaminated soils.
• Regulators and risk assessors evaluating ecological hazard and land‑disposal suitability.
• Remediation consultants and site managers assessing soil habitat function after contamination or treatment.
• Researchers and ecotoxicologists studying bioavailability and sublethal effects on soil arthropods. Practical uses include screening contaminated sites, supporting contaminated‑land decisions, comparing remediation effectiveness, and complementing chemical analyses with biological effect data.

Related standards

• ISO 11268-2 (earthworm reproduction test)
• ISO 11267 (Collembola reproduction test)
• ISO 15799 and ISO 17616 (guidance on bioassay selection and interpretation)
• OECD test guidelines for soil predatory mites (historical reference and complementary protocols)

Keywords: EN ISO 21285, ISO 21285:2019, soil quality, Hypoaspis aculeifer, soil contaminants, reproduction test, soil ecotoxicology, bioavailability, artificial soil, contaminated sites.