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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
25 September - 20 October 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
2004
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Version / remarks:
2008
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)
Version / remarks:
1996
Deviations:
no
Qualifier:
according to
Guideline:
other: HJ/T 153-2004, The guidelines for the testing of chemicals, Beijing: SEPA
Version / remarks:
2004
Deviations:
no
Qualifier:
according to
Guideline:
other: CRC-MEP, The Guidelines for the Testing of Chemicals, Effects on Biotic Systems, The 2nd edition. Beijing: China Environment Press. 2013:22-29.
Version / remarks:
2nd edition
Deviations:
no
Qualifier:
according to
Guideline:
other: GB/T 21830-2008, Chemicals-Daphnia magna acute immobilisation test, Beijing: SAC
Version / remarks:
2008
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
Appearance: colourless or light yellow viscous liquid
Storage conditions: at room temperature, container tightly closed, flushed with nitrogen.
Specific details on test material used for the study:
Solubility <0.394 mg/L (at 20°C)

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples of 10 mL were taken from the blank control and the limit concentration for analysis at t=0, t=24 and t=48.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: WAFs were prepared by adding the test substance directly to Elendt M7 medium in glass aspirator bottles at the required loading rates. The mixing aspirator bottle was stoppered and the aqueous test substance mixture was stirred for 24 hrs on a magnetic stirplate with a Telfon stirbar at room temperature. At the end of the 24 h, the mixtures were left to settle for 1 h at room temperature. Then the aqueous portion was removed through the outlet of the aspirator stirring bottle.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia
- Source: Nanjing University, Lot no. D20170925D and D20171017D (for dose-range finding and limit study, resp.)
- Age of parental stock: Daphnia magna (<24 hours old) were more than three generations through parthenogenesis.
- Feeding during test: no

ACCLIMATION: no

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Test temperature:
19.7 - 20.4 °C
pH:
7.34 - 7.83 throughout the test
Dissolved oxygen:
8.34 - 8.82 mg O2/L throughout the test
Nominal and measured concentrations:
Nominal concentration: WAF prepared at a loading rate of 100 mg/L
Measured concentrations: 20.4 mg/L at t=0 h, 19.5 mg/L at t=24 h and 21.9 mg/L at t=48 h. The mean measured concentration was calculated to be 20.6 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL glass beakers, fill volume: 50 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Test medium: Elendt M7
- Intervals of water quality measurement: pH, dissolved oxygen and temperature in the controls and treatment groups were monitored at the beginning and end of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-hour light, 8-hour dark

EFFECT PARAMETERS MEASURED: immobilisation at t=24 h and t=48 h
- Other: any abnormal behaviour or appearance was reported at t=24 and t=48 h.

RANGE-FINDING STUDY
- Test concentrations: WAFs prepared at loading rates of 1.00, 10.0 and 100 mg/L.
- Results used to determine the conditions for the definitive study: yes, no immobilisation was observed up to and including the highest tested concentration. The EC50 was expected to be >100 mg/L and therefore a limit test using this concentration was performed.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 20.6 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (dissolved fraction)
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
20.6 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (dissolved fraction)
Basis for effect:
mobility
Details on results:
- No daphnids became immobilised during the limit test. Therefore, the NOEC was the highest tested concentration and the EC50 exceeded the highest tested concentration.
- No abnormal behaviour or other abnormalities were observed during the limit test.
- Test concentrations remained stable during the test period. Since the initial measured test concentration was outside the range 80-120% of the nominal concentration, the effect concentrations were based on the mean measured concentration.
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- 48h-EC50: 1.03 mg/L (95% CI: 0.87-1.23 mg/L)
Reported statistics and error estimates:
The EC50 and 95% confidence limits were calculated by Trimmed Spearman-Karber Method (Version 1.5, USEPA).

Any other information on results incl. tables

Table 1 Measured concentrations in samples taken during the limit test

Nominal Concentration

(mg/L)

Measured TOC Concentration(mg/L)

Mean

0h

24h

48h

blank control

9.75

9.66

9.40

9.60

100 mg/L

20.4

19.8

20.8

20.3

Deduct blank control TOC value

10.7

10.1

11.4

10.7

Concentration of test subtstance

20.4

19.5

21.9

20.6

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
see 'overall remarks' section
Conclusions:
In the toxicity to daphnia study, performed according to OECD guideline 202 and GLP principles, the EC50 of STABiO D-376N was determined to be >20.6 mg/L.
Executive summary:

In a short-term toxicity test, performed according to OECD guideline 202 and GLP principles, STABiO D-376N was assessed for its potential toxicity towards Daphnia magna. Test solutions were prepared as Water Accomodated Fractions (WAFs) for a dose-range finding study and a limit study. The dose-range finding study was performed with WAFs prepared at loading rates of 1.0, 10 and 100 mg/L. Since no immobility of the daphnids was seen at any tested concentration, the final test was performed as a limit test with a WAF prepared at a loading rate of 100 mg/L. The test solution was tested in 4 replicate vessels containing 5 daphnids each, next to 4 replicates of a blank control. The exposure period was 48 hours and the test was performed under static conditions. Samples were taken from the test solution at t=0, t=24 and t=48 h for determination of actual exposure concentrations by TOC analysis. The test concentration showed to remain stable over the test period and therefore effect concentrations were based on the mean measured concentration which was calculated to be 20.6 mg/L. No immobility or abnormal behaviour was observed in the daphnids during the exposure period. Therefore, the 48h-EC50 for Daphnia magna exposed to STABiO D-376N was determined to be >20.6 mg/L.

The acceptability criteria were met and the study was considered to be valid.