ISO 14507:2003

Overview

ISO 14507:2003 - Soil quality - Pretreatment of samples for determination of organic contaminants - specifies laboratory pretreatment methods to prepare soil test samples for analysis of organic contaminants. The standard defines three routes depending on compound volatility and sample properties: (1) volatile organic compounds, (2) moderately volatile to non‑volatile compounds where accurate, reproducible results are required (including cryogenic grinding), and (3) non‑volatile compounds or field‑moist requirements where reduced accuracy is acceptable or particles are already < 2 mm. The goal is to produce a test portion whose contaminant concentration reflects the original soil without altering the chemical species.

Key topics and requirements

• Three pretreatment paths:
  • Volatile organics (boiling point < 300 °C): obtain core subsamples and extract promptly; composite samples risk severe losses of volatiles.
  • Moderately volatile/non‑volatile (boiling point > 300 °C) requiring high accuracy: chemical drying with liquid nitrogen (−196 °C) and cryogenic crushing in a cross‑beater mill with a 1 mm sieve to improve homogeneity and extraction yield.
  • Non‑volatile or field‑moist samples: do not dry or grind if extraction requires field‑moist material or if particles are already < 2 mm and contaminants are homogeneously distributed.
• Particle size considerations: 2 mm is the threshold for deciding whether grinding is necessary; ground material is typically reduced to < 1 mm for representative subsampling.
• Sample handling and storage: store samples below 10 °C and analyze as soon as possible; typical analytical test portions are on the order of ~20 g.
• Apparatus and materials: cross‑beater mill (1 mm sieve), Dewar and liquid nitrogen, core cutters, PTFE‑lined screw caps (glass/polyethylene containers), gloves for cryogenic work.
• Reagents and preparation: e.g., anhydrous sodium sulfate heated (~550 °C for at least 6 h) to remove organics; clean sand/gravel and magnesium silicate for specific procedures.
• Quality and repeatability: choice of pretreatment affects accuracy and repeatability; cryogenic crushing improves extraction for higher‑boiling compounds.

Applications and users

• Environmental and soil testing laboratories performing organic contaminant analysis (PAHs, PCBs, pesticides, mineral oil fractions)
• Environmental consultants and remediation contractors preparing samples for regulatory compliance or site assessment
• Research institutions studying contaminant fate, bioavailability, and extraction efficiency
• Regulators and accreditation bodies defining standardized sampling/pretreatment protocols

Keywords: ISO 14507:2003, soil quality, sample pretreatment, organic contaminants, volatile organic compounds, cryogenic crushing, liquid nitrogen, sample grinding, particle size 2 mm, extraction.

Related standards

• ISO 10381-1 (sampling programme design)
• ISO 11074-2 (vocabulary; sampling terms)
• ISO 11465 (dry matter and water content determination)
• ISO 11464 (pretreatment for inorganic/physico‑chemical soil characteristics)