EN ISO 7827:2012 specifies a laboratory method for evaluating the “ready” and “ultimate” aerobic biodegradability of organic compounds in water using analysis of dissolved organic carbon (DOC). The test assesses biodegradation by aerobic microorganisms under defined conditions (typically 22 °C ± 2 °C, dark or diffuse light) and is intended for compounds present at DOC concentrations typically between 10 mg/L and 40 mg/L (higher concentrations may be used when justified). Results help determine whether a substance is likely to degrade rapidly and completely in aerobic aquatic environments.
Key topics and technical requirements
- Test principle: DOC removal is measured over time (day 0, at least three intermediate points, and at the end - usually after 28 days or longer) to calculate percent biodegradation.
- Scope limitations: Applicable only to organic compounds that are soluble, non‑volatile (negligible vapour pressure), not significantly adsorbable on glass or activated sludge, and non‑inhibitory to test microorganisms. Not suitable for typical wastewaters (contains water‑insoluble organic carbon not captured by DOC).
- Environmental conditions: Incubation in the dark or diffuse light at 22 °C ± 2 °C in an enclosure free from toxic vapours.
- Test media and reagents: The standard specifies preparation of mineral test media and use of analytical‑grade reagents; reagent and medium composition and preparation details are provided in the standard.
- Data interpretation: Definitions and metrics are included for lag time, degradation time, maximum level of biodegradation, and terms “ready” and “ultimate” biodegradability - guidance on interpreting curves and pass/fail type conclusions is supplied.
- Quality/validity checks: Requirements for controls, blanks, and checks for inhibitory effects are described; alternative methods to assess inhibition (e.g., referenced standards) are acknowledged.
Practical applications and users
This standard is used by:
- Environmental and analytical laboratories performing biodegradability testing
- Chemical manufacturers assessing environmental fate for regulatory submissions
- Regulatory agencies and authorities reviewing biodegradability data
- Consultants and ecotoxicology specialists advising on product registration and environmental risk
- Wastewater treatment researchers for evaluating compound degradability (with caveats)
Practical uses:
- Classifying chemicals as ready or ultimate biodegradable for regulatory dossiers
- Supporting environmental risk assessments and substance stewardship
- Comparing intrinsic biodegradability of formulation components
- Supplementing other biodegradation data (respirometry, CO2 evolution)
Related standards
- ISO 8245 - TOC/DOC determination guidance
- ISO 9408 - Ultimate biodegradability by oxygen demand (respirometry)
- ISO 9439 - CO2 evolution test for ultimate biodegradability
- ISO/TR 15462 - Alternative biodegradation methods (guidance)
- ISO 8192 - Methods to assess inhibitory effects (referenced)
Keywords: EN ISO 7827:2012, ISO 7827, DOC method, dissolved organic carbon, aerobic biodegradability, ready biodegradability, ultimate biodegradability, water quality, biodegradation testing.