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Administrative data

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2020-03-20 to 2020-07-07
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2020
Report date:
2020

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Qualifier:
according to guideline
Guideline:
other: OECD. Series on testing and assessment No. 23 (Second Edition) Guidance Document on Aqueous-phase Aquatic Toxicity Testing of Difficult Test Chemicals. Paris: OECD, Adopted February 8, 2019.
GLP compliance:
yes (incl. QA statement)

Test material

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
The test solutions were filtered through 0.45 µm aqueous phase PES filter membranes (the first 5 mL - 10 mL filtrates were discarded) before analyzing. The samples were analyzed at the sampling day.

Test solutions

Vehicle:
no
Details on test solutions:
0.532 g test substance was weighed into a beaker and dissolved with a small amount of test water. The mixture was transferred into a 5 L-jar and diluted with test water to 5000 mL to obtain the nominal concentration of 106 mg/L test suspension (The nominal concentration of main constituent was 100 mg/L calculated based on the purity of 93.9%). The suspension was stirred with a magnetic stirrer for about 48 hours. Then the mixture was filtered through 0.45 μm polyether sulfone (PES) filter membranes to discard the insoluble particles, and the nominal concentration of 106 mg/L saturated solution (100% LS) was obtained and used in the test directly.

Test organisms

Test organisms (species):
other: Rare Minnow (Gobiocypris rarus)
Details on test organisms:
Rare Minnow (Gobiocypris rarus), the batch number was FGr20191106-1115. Before the start of the test, Rare Minnow (Gobiocypris rarus) were acclimated for 47 days under the same conditions of the test (water quality: dechlorinated tap water;
temperature: 23 °C ± 2 °C; photoperiod: 14 h light / 10 h darkness). The dissolved oxygen concentration duing acclimation was kept above 80% of the air saturation value.
The fish were fed one time every workday until 24 hours before the start of the test. The mortality was 0% diring the 7 days prior to the start of the test, which met the requirement of mortalities being less than 5% of the population.

Study design

Test type:
semi-static
Water media type:
other: Dechlorinated tap water
Limit test:
yes
Total exposure duration:
96 h

Test conditions

Hardness:
110 mg/L (expressed as CaCO3)
Test temperature:
24.2 °C to 24.7 °C
pH:
8.07 to 8.43
Dissolved oxygen:
80% to I 00%
Nominal and measured concentrations:
Nominal concentration of main constituent was 100 mg/L calculated based on the purity of 93.9%.
The measured concenh·ations of test substance in 100%LS test group at 0 h (new solution), 24 h (old solution) and 72 h (new solution), 96 h (old solution) were all lower than LOD of 0.0324 mg/L.
Details on test conditions:
The photoperiod was 14 h light / 10 h darkness.
The fish were not fed during the exposure period.
7 fish / test vessel, 0.15 8 g fish / L
7 fish / group, 14 fish in total
Reference substance (positive control):
yes
Remarks:
K2Cr2O7

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 106 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
Nominal concentration of 106 mg/L saturated concentration (the measured concentration of test substance was lower than the LOD of 0.0324 mg/L)
Basis for effect:
mortality (fish)
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
106 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
Nominal concentration of 106 mg/L saturated concentration (the measured concentration of test substance was lower than the LOD of 0.0324 mg/L)
Basis for effect:
mortality (fish)
Duration:
96 h
Dose descriptor:
LC100
Effect conc.:
> 106 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
Nominal concentration of 106 mg/L saturated concentration (the measured concentration of test substance was lower than the LOD of 0.0324 mg/L)
Basis for effect:
mortality (fish)
Results with reference substance (positive control):
The test results showed that (the test was conducted on February 26, 2020), the 96 h - LC50 of the reference substance (K2Cr2O7) to Rare Minnow (Gobiocypris rarus) was 215 mg/L and the 95% confidence limits ranged from 171 mg/L to 270 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The mortality of blank control was 0% at the end of the test, which met the validity criterion that the mortality should not exceed 10%. The dissolved oxygen concentration in the test solutions ranged from 80% to 100% of the air saturation value.
Conclusions:
The acute toxicity of test substance to Rare Minnow (Gobiocypris rarus) was conducted as limit test under semi-static conditions (24 h intervals). At the end of the test, the cumulative mortality of test fish in the 100%LS test group was 0%.
Hence, the 96 h - LC50 of test substance for Rare Minnow (Gobiocypris rarus) was greater than the nominal concentration of 106 mg/L saturated concentration (the measured concentration of test substance was lower than the LOD of 0.0324 mg/L)-
Executive summary:

The purpose of the study is to evaluate the possible toxicity of the rest substance to Rare Minnow ( Gobiocypris rarus) for a period of 96 h.

The fish were exposed to the test substance preferably for a period of 96 hours. Mortalities and abnormalities were recorded at 24 h, 48 h, 72 h and 96 h. The calculated concentration of test item which causes death in 50% of the test organisms (LC50) expressed with 24 h-LC50, 48

h-LC50, 72 h-LC50, 96 h-LC50 were determined. At the same time, the highest test concentration without mortalities (LC0) and the lowest test concentration at which all test organisms are dead (LC100) within the period of the test, were determined.

At the end of the test, the cumulative mortality of test fish in the 100%LS test group was 0%.

Hence, the 96 h - LC50 of test substance for Rare Minnow (Gobiocypris rarus) was greater than the nominal concentration of 106 mg/L saturated concentration (the measured concentration of test substance was lower than the LOD of 0.0324 mg/L)-