Overview - ISO 15192:2025 (Cr(VI) in soil and waste)
ISO 15192:2025 specifies a validated laboratory method for the determination of chromium(VI) [Cr(VI)] in solid material (soil and waste) using alkaline digestion followed by ion chromatography with spectrophotometric detection. The method is applicable to solid samples with Cr(VI) mass fractions above 0,1 mg/kg. It clarifies safety, sample pretreatment, digestion, instrumental setup, calibration, quality control, calculation and reporting requirements. Note: results are not valid for strongly reducing or oxidising waste matrices.
Key topics and technical requirements
- Alkaline digestion: extracts soluble, adsorbed and precipitated Cr(VI) while minimizing redox interconversion. Three criteria must be met: complete solubilization of Cr(VI), no reduction of native Cr(VI) to Cr(III), and no oxidation of native Cr(III) to Cr(VI).
- Prevention of redox artefacts: addition of Mg in phosphate buffer to alkaline solution reduces air oxidation of Cr(III); procedural controls minimize Cr(III) ↔ Cr(VI) interconversion.
- Separation and detection: ion chromatography separates Cr(VI) from interferences; detection is by spectrophotometry - direct UV (365 nm) or more sensitive post‑column derivatisation with 1,5‑diphenylcarbazide (540 nm).
- Calibration and matrix effects: high-salt alkaline extracts require matrix‑matched calibration, sample dilution, internal standards or standard addition; method validation on alkaline extracts is mandatory.
- Quality control: blank solutions, method verification (including use of lead or barium chromate as verification standards), duplicate and spiked samples, and interpretation guidelines are specified.
- Applicability limit: reporting threshold for solids > 0,1 mg/kg Cr(VI).
- Safety: Cr(VI) compounds are genotoxic and carcinogenic; strict lab safety and national regulations apply.
Practical applications and users
Who uses ISO 15192:2025:
- Environmental and commercial analytical laboratories performing Cr(VI) testing in soils and waste
- Regulatory agencies and compliance testing bodies enforcing soil and waste quality limits
- Remediation contractors, site consultants and environmental engineers assessing contaminated sites
- Research institutions validating Cr speciation methods
Practical uses include compliance monitoring, site assessment, waste characterization, remediation verification and risk assessment.
Related standards
Normative and referenced documents include:
- ISO 8466-1 (calibration/evaluation of analytical methods)
- ISO 11464 (sample pretreatment)
- ISO 11465 (dry residue/water content)
- EN 15002, EN 15934, EN 16179 (waste/soil test portion and pretreatment guidance)
Keywords: ISO 15192:2025, chromium(VI), Cr(VI), alkaline digestion, ion chromatography, spectrophotometric detection, soil testing, waste characterization, Cr speciation.