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Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From January 25, 2021 to January 29, 2021

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

13th April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch No.: CN0190301
Purity: 98.4%

Analytical monitoring:

yes

Details on sampling:

Analysis of the concentration of the test item was performed in 0 hour fresh solution and 48 hours old solution.

Vehicle:

yes

Details on test solutions:

Test concentration: 100 mg/L, a control group was conducted concurrently.
Method of preparation of test solutions: 0.0250 g test item was weighed and dissolved in 250 mL of test water directly. After the test item was dissolved completely, the solution was used for exposure.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Age at study initiation (mean and range, SD): less than 24 hours old and not the first brood progeny.
- Source: Applied Chemistry Department Pesticide Environmental Evaluation Laboratory of China Agricultural University.

ACCLIMATION
- Acclimation period: 1d
- Acclimation conditions (same as test or not): same

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

140 to 250 mg/L (as CaCO3)

Test temperature:

18~22oC

pH:

within 6 - 9

Dissolved oxygen:

not less than 3 mg/L during the test period

Nominal and measured concentrations:

Nominal 100 mg/L; Measured 81.7 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 200 mL glass beakers
- Volume of solution: 50 mL per vessel
- Aeration: Before usage, the water was aerated for more than 24 hours to attain dissolved oxygen saturation. During the test, there was no aeration to vessels.
- No. of organisms per vessel: 5 daphnia
- No. of vessels per concentration (replicates): 4 replicates
- No. of vessels per control (replicates): 4 replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: the dilution water was tap water after being treated with Aquapro Pure Water System
- Total organic carbon: < 2 mg/L

OTHER TEST CONDITIONS
- Adjustment of pH: During the test, there was no pH adjusting or feeding.
- Photoperiod: 16 hr light: 8 hr dark
- Light intensity:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Biological observation: Observation intervals: 24 and 48 hours after exposure
Water quality and physicochemical measurements:
Water total hardness: at the beginning of the test.
Dissolved oxygen and pH: in all fresh and old media for both control and test group. The residual initial solution was used to measure dissolved oxygen and pH of the fresh solutions. Dissolved oxygen and pH were measured at all treatments of old solutions.
Temperature: monitored continuously by automatic temperature monitoring system and recorded.

RANGE-FINDING STUDY
- Test concentrations: 0.1, 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: During the period of 48 hours, no immobilization nor any toxic signs were observed in the control group and the test groups of 0.1, 1 and 10 mg/L, only 1 daphnia was immobilized in the test group of 100 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate as reference item was tested for EC50 as a means of assuring that the test conditions are reliable four times a year in the laboratory.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Physicochemical Measurements in the Definitive Test:
The determined values of dissolved oxygen were 9.07 - 9.73 mg/L, the pH values were between 7.99 ~ 8.17 and the max difference was 0.18. Total hardness of test water was 200 mg/L (as CaCO3). The temperature was 18.9 ~ 19.4 oC, the difference was 0.5 oC. They were in the allowed range specified in Conditions of exposure.
Toxic Signs in the Definitive Test:
During the 48-hour exposure period, no immobilization and abnormal behavior or appearance was observed in the control group and the test group of 100 mg/L.
Verification of Test Concentration in the Definitive Test:
The concentration of test item was determined in sample of test media by LC-MS/MS. Analysis of the concentration of the test item was performed in 0 hour fresh solution and 48 hours old solution. The results showed that for the test solution of 100 mg/L, the determined concentration in fresh media was 81.7 mg/L, which was 81.7% of the nominal concentration. The determined concentration in old media was 96.8 mg/L, which was 96.8% of the nominal concentration. The test concentration was satisfactorily maintained in the range of 80 ~ 120% of the nominal concentration.

Results with reference substance (positive control):

EC50-24 h of potassium dichromate to Daphnia magna was 1.17 mg/L, and the 95% confidence limits was 0.99 ~ 1.39 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

According to the results of test and based on the nominal concentration, the 48-hour EC50 of the test item to Daphnia magna was great than 100 mg/L.

Executive summary:

A Daphnia acute immobilisation test of the test item was conducted with Daphnia magna over a 48-hour exposure period, according to OECD Guideline 202 under GLP.

According to the results of test and based on the nominal concentration, the 48-hour EC50 of the test item to Daphnia magna was great than 100 mg/L.

Description of key information

A Daphnia acute immobilisation test of the test item was conducted with Daphnia magna over a 48-hour exposure period, according to OECD Guideline 202 under GLP.

According to the results of test and based on the nominal concentration, the 48-hour EC50 of the test item to Daphnia magna was great than 100 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L