Overview
ISO 5667-15:2009 - Water quality - Sampling - Part 15 provides authoritative guidance on the preservation, handling and storage of wet sludge, sediment and suspended‑matter samples (sewage, waterworks sludge, freshwater and saltwater sediments) up to the point of laboratory examination. It is part of the ISO 5667 series on water quality sampling and applies specifically to wet samples destined for chemical, physical, radiochemical and biological analyses.
Key topics and requirements
- Scope and applicability: Procedures apply only to wet sludge, sediments and suspended matter; dried or freeze‑dried sample guidance is covered by other standards.
- Preservation principles: Emphasises that preservation should begin immediately after collection to prevent biodegradation, volatilization, redox changes or physical disturbance. No single universal method - collect sub‑samples preserved differently to cover multiple analyses.
- Analytical-specific guidance:
- Chemical: factors affecting partitioning (pH, redox, salinity, particle size) and effects of freezing/microbial activity.
- Physical: preserve structure, texture and layering; avoid agitation or thermal treatments that change physical properties.
- Radiochemical: avoid environmental contamination; protect low‑activity samples from laboratory sources.
- Biological: different preservation for bioassays vs ecological surveys; microbial assays often require no fixation.
- Reagents and examples: Recommends analytical‑grade reagents such as deionized water (ISO 3696 Grade 3), sodium sulfate (pre‑heated), zinc acetate, methanol, ethanol and formaldehyde preparations (e.g., 3.7 % final formaldehyde).
- Containers and preparation: Guidance on container selection and preparation to avoid contamination and gas buildup.
- Sample handling workflow: Collection, identification, transport, reception, storage and long‑term options (Annexes include container preparation and nitrogen‑vapor freezer storage).
- Safety: Staff protection (PPE, vaccination, gas and explosion risks) and sample protection measures.
- Documentation and QA: Emphasises labelling, chain of custody and pre‑defined storage conditions and durations (referenced tables in the standard).
Practical applications and users
ISO 5667-15 is used by:
- Environmental laboratories and analysts performing chemical, physical, biological or radiochemical tests
- Water and wastewater utilities managing sludge monitoring programs
- Environmental consultants conducting sediment impact assessments
- Regulatory agencies setting sampling protocols and compliance monitoring
- Research institutions studying contaminant fate and sediment ecology
Benefits include improved sample integrity, reproducible analytical results and consistent chain‑of‑custody and safety practices.
Related standards
- ISO 5667 series (other parts on sampling methods)
- ISO 3696 - Water for analytical laboratory use
- ISO 18512 - Storage of (freeze)‑dried samples (referenced for dried sample guidance)
- ISO 16720 - Freeze‑drying guidance
Keywords: ISO 5667-15, water quality sampling, sludge preservation, sediment sample handling, sample storage, sample transport, laboratory analysis.