ISO 18400-201:2017

Overview

ISO 18400-201:2017 - Soil quality - Sampling - Part 201: Physical pretreatment in the field specifies approved methods for physically pretreating soil samples immediately after collection, while still on site. The standard limits field pretreatment to: sample division (subsampling), production of composite samples, and selection of specific fractions of the sampled material. It expressly excludes procedures for biological/microbiological samples and sampling for volatile components, and it does not provide guidance on particle-size reduction (see related standards).

Key technical topics and requirements

• Scope and limits: Field pretreatment methods only; no particle size reduction; not applicable to biological or VOC-containing samples (ISO 22155 addresses volatiles).
• Preliminary considerations and sampling plan integration: Pretreatment actions must be defined in the sampling plan to preserve representativeness and traceability.
• Homogenization and subsampling: Procedures to obtain representative laboratory samples including homogenization principles and minimum subsample size requirements.
• Subsampling methods: Standardized field techniques described include:
  • Long pile and alternate shovel
  • Coning and quartering
  • Riffling
  • Tyler divider application
  • Mechanized turntable (rotating divider)
  • Selective subsampling by sieving or hand-picking to target specific particle-size fractions
• Macro-aggregate handling: Guidance for manual reduction of large aggregates to improve representativeness.
• Composite sample formation: Rules for combining increments or parts of samples to form a composite field sample.
• Equipment, safety, packaging and storage: Requirements for suitable field equipment, safe working practices, and interim packaging/storage to protect sample integrity until laboratory receipt.
• Reporting: Mandatory documentation of pretreatment actions, methods used, and sample identification to ensure traceability.

Practical applications and users

ISO 18400-201 is intended for professionals and organizations involved in soil investigation and environmental assessment, including:

• Environmental consultants and field technicians conducting contaminant surveys
• Geotechnical and agricultural soil sampling teams
• Laboratories receiving field-pretreated samples
• Regulatory agencies and remediation contractors specifying sampling protocols

Typical uses:

• Reducing large field samples to manageable laboratory samples while maintaining representativeness
• Creating composite samples from multiple increments for screening-level surveys
• Selecting targeted particle-size fractions for chemical analysis (where permitted)

Related standards

• ISO 18400 series (sampling framework and strategies)
• ISO 22155 (sampling for volatile components)
• ISO 11464, ISO 14507, ISO 23909 (particle-size reduction and laboratory pretreatment)
• ISO 18400-105, ISO 18400-107 (packaging, storage, reporting)

Using ISO 18400-201:2017 ensures consistent, defensible field pretreatment practices that protect sample integrity and support reliable soil quality assessments.