Overview
EN ISO 5667-3:2024 - Water quality - Sampling - Part 3: Preservation and handling of water samples (ISO 5667-3:2024) specifies general requirements for the preservation, handling, transport and storage of water samples intended for physicochemical, chemical, hydrobiological, microbiological and radiochemical analyses. This sixth-edition international standard updates and supersedes the 2018 edition and is intended especially for situations where samples cannot be analysed on site and must be transported to a laboratory.
Key topics and technical requirements
- Scope and applicability: Applies to most water-sampling matrices except ecotoxicological assays, biological assays (ISO 5667-16), passive sampling (ISO 5667-23) and microplastics (ISO 5667-27).
- Sample chain of custody: Guidance on documentation, identification and sample reception to preserve data integrity during transport and storage.
- Containers and materials: Selection, preparation and on-site filtration considerations for sampling containers and materials to minimise contamination and preserve analytes.
- Reagents and preservation techniques: Use of reagents, sample preservation methods and handling procedures; Annex A provides techniques for preservation while Annex B covers container preparation.
- Storage and transport: Recommended storage conditions and transport practices, including temperature control and maximum holding times (default conditions provided in Tables A.1–A.5).
- Analyte-specific guidance: Tables A.1–A.5 list validated preservation times/conditions and best practices for inorganic, organic, microbiological and radiochemical analytes.
- Validation of holding times: Emphasises the need to validate storage times and methods; reference to ISO/TS 5667-25 for validation protocols and ISO 17034 where relevant.
- Flow diagram and decision framework: A flow diagram helps select appropriate preservation and storage methods; order of preference for methods is: validated method → method provided by reference → best practice.
Practical applications
- Designing and implementing sampling programmes where samples are transported to laboratories.
- Standardising sample handling for environmental monitoring, potable water testing, wastewater analysis and radiochemical measurements.
- Reducing sample degradation and contamination risk during transport and storage, improving analytical reliability.
Who should use this standard
- Environmental laboratories and analytical chemists
- Water utilities and treatment operators
- Environmental consultants and field samplers
- Regulatory bodies and accreditation assessors
Related standards and references
This standard is essential for anyone responsible for reliable water quality sampling, preservation and transport to ensure valid, traceable analytical results.
