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GB/T 21805-2025Chemicals - Alga growth inhibition test (English PDF)

化学品　藻类生长抑制试验

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

October 5, 2025

Implementation date

February 1, 2026

Scope

GB/T 21805-2025 is the English-translated version of 化学品　藻类生长抑制试验.

GB/T 21805-2025 is the Chinese standard "Chemicals - Alga growth inhibition test". Its scope clause reads: This document specifies the test substance information, test principle, reference material, test method, test procedure, and quality control details for chemical algae growth inhibition tests.

Quantity assurance and quality control, data and reporting. This document is applicable to evaluating the effects of test substances with low volatility, high environmental stability, and water solubility under test conditions on algal growth.

The sound. If testing volatile, strongly adsorbent, colored, insoluble or poorly soluble substances in water, as well as substances that may affect the nutrients in the culture medium.

For test subjects requiring efficient utilization of nutrients or minerals, modifications to the test procedure are necessary (e.g., using a closed system, appropriate test volume). (devices, etc.). Its clauses include terms and definitions.

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Document preview — GB/T 21805-2025

National Standard of the People's Republic of China

ICS: 13.300
Classification: A 80
Replacing: GB/T 21805-2008

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

Preface
1.Scope
2 Normative References
3.Terms and Definitions
4.Test substance information
5.Experimental Principle
6.Reference material
7.Test Methods
8.Experimental Procedure
9.Quality Assurance and Quality Control 6.
10 Data and Reports
Appendix A (Informative) 11 Experimental Algal Species
Appendix B (Informative) Culture Medium
Appendix C (Informative) Example 16 of Algal Cultivation Process
Appendix D (Informative) Nonlinear Regression Data Analysis
References

1 Scope

This document specifies the test substance information, test principle, reference material, test method, test procedure, and quality control details for chemical algae growth inhibition tests.

Quantity assurance and quality control, data and reporting.

This document is applicable to evaluating the effects of test substances with low volatility, high environmental stability, and water solubility under test conditions on algal growth.

The sound. If testing volatile, strongly adsorbent, colored, insoluble or poorly soluble substances in water, as well as substances that may affect the nutrients in the culture medium.

For test subjects requiring efficient utilization of nutrients or minerals, modifications to the test procedure are necessary (e.g., using a closed system, appropriate test volume).

(devices, etc.)

2 Normative references

This document has no normative references.

3 Terms and Definitions

The following terms and definitions apply to this document.

3.1 biomass

Dry weight of living organisms per unit volume of test medium.

Note. For example, how many milligrams of dry algae are contained in each liter of test solution. Biomass is usually defined as mass, but in this document, it refers to the mass per unit volume.

Biomass is usually measured by replacing the number of cells per unit volume or fluorescence.

3.2

The ratio of standard deviation to mean.

Note. The coefficient of variation is a dimensionless number, used for comparisons between samples, and is usually expressed as a percentage, denoted as CV%. The mean ratio of each parallel sample in the control group to the control group is...

The average value of the coefficient of variation of the length rate is calculated as follows.

a) Calculate the coefficient of variation of the average specific growth rate of each parallel control group at each stage;

b) Average all the data obtained in a) above to obtain the average coefficient of variation of the growth rate of each parallel control group.

3.3 Effect concentration (ECx)

The concentration of the test substance that causes a decrease in the growth of the test organism by x% compared to the control group within a given measurement period.

Note. ECx is divided into ErCx based on growth rate and EyCx based on growth amount.

3.4 algal growth medium

Artificially synthesized algae culture medium.

Note. In this document, when algae are exposed to the test substance, the test substance is usually dissolved in the culture medium.

3.5 growth rate

The exponential growth rate of biomass during exposure.

GB/T 21617 | GB 23350 | GB/T 21622 | GB/T 21796 | GB/T 21795 | […]

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 24 pages — is available in the English PDF.

Referenced standards

Cited by

Editions of GB/T 21805

Edition	Title	Revision	Status
GB/T 21805-2025	Chemicals - Alga growth inhibition test	current edition	Current
GB/T 21805-2008	Chemicals -- Alga growth inhibition test	previous edition	In force

This page sells the current edition, GB/T 21805-2025. Earlier editions are listed for reference only.

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