GB/T 36700.4-2018

Chemicals—Guidance on hazard classification to the aquatic environment—Part 4: Degradation (English Version)

Standard No.

GB/T 36700.4-2018

Language

Chinese, Available in English version

Release Date

2018

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Latest

GB/T 36700.4-2018

Scope

An overview of the aquatic hazard classification of chemicals involving degradation, interpretation of degradability data, general interpretation issues and guidance on the determination method

Introduction

The core role of degradability in the classification of aquatic environmental hazards

GB/T 36700.4-2018, as a key component of the aquatic environmental hazard classification system for chemicals, systematically standardizes the interpretation method and judgment process of degradability data. Degradability, as an inherent characteristic of chemicals, directly affects their persistence and cumulative risk in the aquatic environment.

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Technical Framework of Degradability Assessment

Assessment Type	Standard Method	Judgment Threshold	Applicable Scenarios
Rapid Biodegradation	GB/T 21801~21857 Series	28-day Degradation Rate ≥70%	Priority Assessment Method
Inherent Biodegradability	GB/T 21816~21818	Degradation Potential Assessment	Secondary Assessment
Simulation Test	ASTM E1279, etc.	Half-life <16 days	Environmental relevance verification

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Analysis of key judgment factors

1. Validity of rapid biodegradability data

The standard clearly requires the evaluation:

• Test substance concentration: Toxicity interference must be excluded within the range of 2-100mg/L
• 10-day observation period: The passing level must be reached within 10 days from the time when degradation reaches 10%
• Inoculum adaptability: The use of pre-adapted inoculum is prohibited

2. Principles for the application of alternative data

When standard test data is lacking:

• BOD₅/COD≥0.5 can be used as auxiliary evidence
• Soil degradation data must meet the conditions of no pre-adaptation and environmental concentration
• Only negative conclusions are accepted for QSAR prediction results

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Technological evolution and implementation recommendations

This standard reflects three major advances in degradation assessment technology:

1. Shifting from single endpoint assessment to multi-evidence weight analysis
2. Expanding from laboratory conditions to environmental simulation verification
3. Establishing a hierarchical assessment strategy for complex substances

Recommendations for enterprise implementation paths

• Data collection phase: Prioritize the compilation of rapid biodegradability test reports
• Gap analysis: Verify the compliance of the test method against Appendix C of the standard
• Expert evaluation: Use the weight of evidence approach for conflicting data