ISO 11269-2:2012

Overview

ISO 11269-2:2012 - "Soil quality - Determination of the effects of pollutants on soil flora - Part 2" defines a standardized plant emergence and early growth test to evaluate the quality and habitat function of contaminated soils. The method measures how at least two terrestrial plant species (one monocot and one dicot) respond in terms of emergence and early biomass when grown in test soils or mixtures of test and control soils. It is applicable to soils of unknown quality from contaminated sites, amended soils, or soils after remediation.

Key Topics and Requirements

• Test principle: Compare seedling emergence and early growth in test soil against a reference or standard control soil and/or dilution series to derive dose–response data.
• Species: Minimum two species (recommended: oat [Avena sativa] as monocot, and turnip rape/wild turnip [Brassica rapa] as dicot). Other species may be used if justified and meeting validity criteria.
• Endpoints: Emergence percentage and shoot dry mass (per plant or per pot); optional endpoints include shoot/root length and root dry mass (root endpoints can be more sensitive).
• Duration and sampling: Record emergence when 50% of control seedlings have emerged; thin to set density; harvest after about 2–3 weeks to determine biomass.
• Dose–response metrics: NOEC (no observed effect concentration), LOEC (lowest observed effect concentration), and ECx/ERx (x % effect concentrations/rates) are calculated from soil mixture series.
• Materials and equipment: Non-porous or glazed pots (top diameter ~85–95 mm); automatic/wick watering (glass-fibre wicks) recommended to maintain moisture; guidance on soil preparation and nutrient supply is provided.
• Validity and safety: Tests must meet specified validity criteria (see Clause 11). Warning: handling contaminated soils may pose chemical or biological hazards - follow appropriate safety precautions.

Applications and Users

• Environmental consultancies performing ecotoxicological site assessments
• Soil scientists and remediation practitioners evaluating habitat function post-remediation
• Accredited environmental laboratories conducting bioassays for contaminated land
• Regulators and risk assessors using biological endpoints to inform remediation targets and land-use decisions

Practical benefits include biological evidence of soil impairment, screening of remediated or amended soils, and input to multi-line weight-of-evidence assessments.

Related Standards

Relevant complementary ISO standards cited in ISO 11269-2 include:

• ISO 11269-1 - root growth inhibition test (related plant ecotoxicology)
• ISO 22030 - chronic toxicity in higher plants (related biological methods)
• Soil characterization and sampling standards: ISO 10381-6, ISO 10390, ISO 10694, ISO 11260, ISO 11277, ISO 11465

Using ISO 11269-2 as part of an integrated soil-quality testing program provides standardized, comparable biological data on contaminated-soil impacts to flora and soil habitat function.