GB/T 42366-2023 (English Version)

Standard No.: GB/T 42366-2023
Language: Chinese, Available in English version
Release Date: 2023
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 42366-2023

Scope: This document describes the experimental principle, test substance information, reference substances, test preparation, test procedures, quality assurance and quality control, data processing, and reporting of the chemical reproduction test on Lymnaea stagnalis. This document is used to evaluate the potential effects of chemicals on the survival and reproduction of the hermaphroditic freshwater snail Lymnaea stagnalis under long-term exposure.

Introduction

Analysis of the core content of the standard

Test principle and design

This test evaluates the effects of chemicals on the reproduction of Lymnaea sibiricum through a 28-day exposure period. The main observation indicators include:

Basic endpoints: Survival of parent snails and egg production
Additional endpoints: Shell length growth rate and number of eggs laid by a single egg group

Comparison of key test parameters

Parameter category	Standard requirements	Quality control threshold
Test period	28 days
Temperature control	20±1℃	Short-term fluctuation≤±2℃
Dissolved oxygen	＞6mg/L	Saturation≥60%
Mortality rate of control group	—	≤20%

Key points of the experiment

Biological preparation specifications

Select Stillwater Lymnaea snails with a shell length of 2.5-3.0cm, which must meet the following requirements:

Accustomed in a laboratory parasite-free environment for ≥2 generations
Verification of reproduction during the adaptation period (≥1 egg group/container)
Random grouping to ensure no significant difference in shell length (p≥0.05)

Concentration design principles

Formal test needs to be set up:

Geometric series concentration: 5 concentration groups, interval coefficient ≤3.2
Parallel requirements: 6 parallels/concentration, 5 spirals/parallel
Reference material: Cadmium chloride EC50=40-230μg/L (Cd meter)

Data processing and result interpretation

Calculation of core toxicity parameters

Parameters	Calculation formula	Statistical method
ECx	Three-parameter exponential model fitting	Bayesian inference (95%CI)
NOEC/LOEC	Reproduction/NID ratio	Williams/Jonckheere test
TWA	Exponential decay model integral	Time-weighted average method

Implementation recommendations

Special material handling

For poorly soluble substances:

Co-solvent concentration ≤20μL/L
A solvent control group needs to be set up
DMSO, acetone and other low-toxic solvents are preferred

Quality Assurance Measures

Concentration Verification: Measure the new and old solutions of the high and low concentration groups every week
Abnormal Handling: When the mortality rate is greater than 15%, the entire group of data must be discarded
Data Recording: Record the reproduction volume in full according to the format of Appendix E

Analysis of Standard Technology Evolution

This standard fills the gap in the test method for reproductive toxicity of hermaphroditic aquatic organisms. The main innovations include:

Test endpoint innovation: For the first time, the number of individual survival days (NID) was included in the calculation of reproduction volume
Statistical model optimization: Gamma-Poisson mixed distribution was used to handle parallel differences
Quality Control Strengthening: New water quality monitoring indicators such as hardness (140-250mg/L CaCO3) were added

Compared with the OECD 243 Guidelines, this standard adds the time-weighted average concentration calculation method (Appendix C) and abnormal egg classification criteria (Appendix B), which significantly improves data reliability.

GB/T 42366-2023 Referenced Document

GB/T 21801 Chemicals.Ready biodegradability.Manometric respirometry test
GB/T 21802 Chemicals.Ready biodegradability.Modified MITI test(I)
GB/T 21803 Chemicals.Ready biodegradability.DOC die-away test
GB/T 21831 Chemicals.Ready biodegradability:Closed bottle test
GB/T 21856 Chemicals.Ready biodegradability.CO evolution test
GB/T 21857 Chemicals.Ready biodegradability.Modified OECD screning test

GB/T 42366-2023 history

2023 GB/T 42366-2023 Propagation experiment of chemical hydrostatic snails