Overview
ISO 5667-9:1992 - Water quality - Sampling - Part 9: Guidance on sampling from marine waters provides practical guidance for designing sampling programmes, choosing sampling techniques, and handling and preserving sea water samples from tidal waters (estuaries, tidal inlets, coastal zones and the open sea). It focuses on chemical and physical determinands and explicitly excludes collection methods for microbiological or biological examinations (see ISO 8199 for microbiology). Main objectives include quality characterization, long‑term quality control, investigations for specific causes, and assessing effects of man‑made structures.
Key topics and technical requirements
- Scope & objectives: Guidance for tidal and marine waters including spatial/temporal characterisation, trend monitoring and impact assessment of structures (ports, jetties, barrages).
- Sampling programme design: Emphasis on preliminary surveys and statistical planning to locate representative sampling points (depth profiles, area profiles, spot and composite samples).
- Sample types: Definitions and use of spot samples, depth profile samples, area profile samples, and composite samples (time/flow‑weighted).
- Containers & contamination control: Prefer glass or inert materials; avoid fragile containers at sea. Minimise absorption and contamination (use gloves, wash bottles before collection).
- Sampling equipment:
- Open samplers for surface or near‑surface collection (avoid for subsurface due to microlayer contamination).
- Closed‑pipe samplers (tube samplers with valves/stoppers) for defined depths and depth‑integrated composites - internal PTFE coatings and PTFE/silicone seals recommended where contamination risk exists.
- Pumping devices (peristaltic/centrifugal) for dissolved and particulate chemical determinands; not ideal for volatile/gaseous compounds.
- Automatic samplers and integrated monitoring stations for timed discrete sampling, often combined with data loggers and telemetry.
- Operational guidance: Use non‑metallic hydrographic cables for trace metal/hydrocarbon work; allow samplers to “acclimatize” (approx. 5 minutes) before taking samples; avoid rubber internal springs, and use plastic‑coated messenger weights where needed.
- Special considerations: Surface microlayer sampling is difficult to make representative; seabed samples require purpose‑designed devices; tidal excursion and currents must be considered to avoid duplicate sampling of the same water.
Applications
- Coastal and estuarine monitoring and compliance
- Long‑term trend and baseline studies (water quality characterization)
- Effluent/contaminant plume tracing and incident response
- Environmental impact assessments for marine infrastructure
- Design of sampling protocols for research cruises and monitoring stations
Who should use this standard
- Environmental laboratories and QA managers
- Marine scientists and field sampling teams
- Regulatory agencies and water quality authorities
- Environmental consultants and engineering firms involved in coastal works
Related standards
- ISO 5667‑1, ‑2, ‑3, ‑4 (sampling programme design, techniques, preservation, lakes)
- ISO 8199 (microbiological sampling guidance)
- ISO 6107‑2 (vocabulary)
Keywords: ISO 5667-9:1992, water quality sampling, marine waters, tidal waters, sampling techniques, sampling equipment, sample preservation, depth profile, composite samples.