ISO 5667-27:2025

Overview

ISO 5667-27:2025 - "Water quality - Sampling - Part 27: Guidance on sampling for microplastics in water" provides standardized guidance for collecting suspended microplastics from a range of water matrices (domestic water, freshwater, seawater, treated and untreated wastewater). It defines microplastics (particles 1 µm to 5 mm) and gives practical procedures for grab sampling, volume‑reduced sampling (cascade filtration) and net sampling (for example, manta, plankton or neuston nets). The document focuses on sampling methodology, sample handling and quality control; it does not cover chemical, biological/ecotoxicological or physical analysis methods nor pre‑treatment/digestion protocols.

Key Topics and Technical Requirements

• Sampling methods
  • Grab sampling (spot samples) - collect discrete volumes for laboratory separation.
  • Cascade filtration (volume‑reduced sampling) - successive filters of different pore sizes to capture particle size fractions; methods adapted for low, medium and high suspended solid content.
  • Net sampling - surface or near‑surface collection using nets such as manta, plankton or neuston nets.
• Suspended solids categories (for method selection)
  • Low: 1–100 mg/L
  • Medium: 100–500 mg/L
  • High: >500 mg/L
• Quality control
  • Use of field blanks and other blanks to detect contamination during sampling.
  • Recommendations on materials and handling to minimize plastic contamination (e.g., inert filters for blanks).
  • Guidance on sampling volume, frequency, timing and sampling points to reduce variability.
• Apparatus and sample handling
  • Lists of suitable equipment for grab sampling, cascade filtration and net sampling, and instructions for transport and storage to preserve sample integrity.
• Reporting
  • Required sampling report elements to ensure data traceability and comparability.

Practical Applications and Users

ISO 5667-27 is intended for:

• Environmental laboratories and analytical teams setting up microplastics sampling programs
• Water utilities and wastewater operators monitoring plastic contamination
• Governmental and regulatory bodies establishing surveillance or compliance sampling
• Researchers conducting field studies on microplastics distribution in rivers, coastal waters and drinking water supplies
• NGOs and consultants performing baseline surveys and impact assessments

Benefits include improved comparability of datasets, reduced sampling bias, and clearer documentation for monitoring programs.

Related Standards (if applicable)

• ISO 5667 series (general water sampling standards)
• ISO 5667-3 (Preservation and handling of water samples)
• ISO 5667-17 (related sampling guidance)
• ISO/TR 21960 and ISO/TR 22930-1 (terminology and detection/limit definitions referenced)

Keywords: ISO 5667-27, microplastics sampling, water quality, cascade filtration, grab sampling, manta net, field blanks, suspended microplastics, sampling protocol.