ISO 23611-3:2019

Overview

ISO 23611-3:2019 - "Soil quality - Sampling of soil invertebrates - Part 3: Sampling and extraction of enchytraeids" specifies a standardized field and laboratory method for sampling, handling and extracting enchytraeids (potworms) from terrestrial soils. The standard supports the use of enchytraeids as bioindicators for habitat quality, ecological monitoring and assessment of pollutant effects. It applies to most terrestrial biotopes where enchytraeids occur, but excludes very wet/flooded soils and may be difficult to use in extreme geographic/climatic conditions.

Key topics and technical requirements

• Sampling tool: split soil corer (typically 3–6 mm diameter stated in the standard; core length variable) to take destructive cores.
• Core handling: cores are subdivided into cylinders (approx. 3–4 cm height), stored in plastic bags and refrigerated (~4–6 °C). Short-term storage preferably 1–2 weeks (maximum 1 month).
• Extraction method: wet extraction into water-filled bowls using sieves (mesh ≈ 1.0 mm); enchytraeids actively migrate into water. Target extraction efficiency >90%.
• Conditions for extraction: water temperature ~ (12 ± 2) °C; typical extraction durations: 2–7 days for soil, 0.5–2 days for litter. Change water after ~18–24 h (and again after 48 h if needed) to prevent oxygen deficiency. Controlled heating (e.g., 60 W lamp) may speed extraction if applied slowly.
• Laboratory work: microscopic identification (dissecting and high-magnification microscopes), live counting, optional preservation (70% ethanol, Bouin’s fixative, staining agents such as Bengalred or paracarmin). Procedures for biomass determination, data assessment and reporting are included.
• Quality notes: recommends site characterization (soil properties, climate, land use) though these analyses are covered by other ISO standards.

Applications and users

ISO 23611-3:2019 is intended for:

• Soil ecologists and taxonomists conducting community and biodiversity assessments.
• Environmental consultants and regulators performing soil quality monitoring, bioindication and impact assessment of contaminants.
• Research laboratories and long‑term monitoring programs measuring enchytraeid abundance and biomass as indicators of soil function (decomposition, nutrient cycling) and for decisions on remediation or land management.

Practical applications include habitat quality assessment, terrestrial bioindication, pollutant effect evaluation and inclusion of enchytraeid sampling in multi-taxa soil monitoring programs.

Related standards

• ISO 23611‑1, ISO 23611‑2, ISO 23611‑4, ISO 23611‑5 (methods for other soil organisms: earthworms, arthropods, etc.)
• ISO 18400‑101 (field sampling design)
• ISO 10390, ISO 10694, ISO 11272, ISO 11274, ISO 11277, ISO 11461, ISO 11465 (soil pH, particle size, C/N, organic carbon, water‑holding capacity)

Keywords: ISO 23611-3:2019, soil quality, sampling of soil invertebrates, enchytraeids sampling, wet extraction, bioindicators, soil monitoring.