Registration Dossier

Diss Factsheets

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:
06 February 2017 - 13 March 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:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
April 2004
Qualifier:
according to guideline
Guideline:
other: Method C.2 of Commision Regulation (EC) No. 440/2008
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-(2H-benzotriazol-2-yl)-4-tert-butylphenol
EC Number:
221-574-0
EC Name:
2-(2H-benzotriazol-2-yl)-4-tert-butylphenol
Cas Number:
3147-76-0
Molecular formula:
C16H17N3O
IUPAC Name:
2-(5-tert-Butyl-2-hydroxyphenyl)benzotriazole
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 02002IX3
- Expiration date of the lot/batch: 25 August 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature in the dark


Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Sample storage conditions before analysis: samples were stored frozen prior to analysis

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A nominal amount of test item (550 mg) was dispersed in 11 liters of test water with the aid of propeller stirring at approximately 1500 rpm for 24 hours. After 24 hours the stirring was stopped and any undissolved test item was removed by centrifugation at 40000 g for 30 minutes to give a 100% v/v saturated solution.
The prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Controls: The control group was maintained under identical conditions but not exposed to the test item.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): undissolved test item were removed by centrifugation at 40000 g for 30 minutes to produce a 100% v/v saturated solution of the test item

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Feeding during test: daily
- Food type: mixture of algal suspension (Desmodesmus subspicatus) and Tetramin flake food suspension
- Amount: 20 daphnids (4 replicates of 5 animals)
- Frequency: 0, 24 and 48 hours

Study design

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

Test conditions

Test temperature:
19°C - 22°C
pH:
7.8 - 7.9
Dissolved oxygen:
8.4 - 9.2 mg O2/L
Nominal and measured concentrations:
Analysis of the freshly prepared test media at 0 and 24 hours (see Annex 5) showed measured test concentrations to be 0.27 and 0.11 mg/L, respectively. Analysis of the old or expired test preparations at 24 and 48 hours showed measured test concentrations had declined to 0.11 and 0.035 mg/L, respectively. Hence it was considered appropriate to calculate the results based on the geometric mean measured test concentration in order to give a “worst case” analysis of the data.
The geometric mean measured test concentration was determined to be 0.12 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: 150 mL glass beakers
- Aeration: not aerated
- Renewal rate of test solution (frequency/flow rate): renewal at 24 hours
- No. of vessels per concentration (replicates): Four replicate test and control vessels were prepared.

TEST MEDIUM / WATER PARAMETERS
Temperature was maintained at 19 °C to 22 °C throughout the test, while there were no treatment related differences for oxygen concentration or pH.

OTHER TEST CONDITIONS
Throughout the test the light intensity was observed to be in the range 469 to 541 Lux.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Cumulative Immobilized

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
test concentrations of 0.10, 1.0, 10 and 100% v/v saturated solution.

Reference substance (positive control):
yes

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 0.12 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
0.12 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
No sub-lethal effects of exposure were observed throughout the test.
Results with reference substance (positive control):
Exposure conditions for the positive control were similar to those in the definitive test.
A positive control used potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.
The No Observed Effect Concentration is based upon equal to or less than 10% immobilization at this concentration.
The results from the positive control with potassium dichromate were within the normal range for this reference item.
24 hours: EC50 =1.3, NOEC = 1.0, LOEC = 1.8
48 hours: EC50 =1.2, NOEC = 0.56, LOEC = 1.0
Reported statistics and error estimates:
The geometric mean measured test concentrations of the samples were calculated

Any other information on results incl. tables

The results from the filtered test samples suggest that the test item was possibly adsorbing to the filer matrices. There was no significant increase in the dissolved test item concentration obtained from the centrifuged test samples when the preparation period was extended beyond 24 hours. Centrifugation at 40000g was considered most appropriate as the higher measured concentration obtained from the 24-Hour 10000 g sample indicated that not all of the undissolved test item was removed.

Based on this information the test item was prepared using a saturated solution method of preparation at an initial loading rate of 50 mg/L, stirred for a period of 24 hours prior to the removal of any undissolved test item by centrifugation at 10000 g for 30 minutes to give a nominal test concentration of approximately 0.028 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Test was considered to be valid given that none of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.
Conclusions:
The acute toxicity of the test item to the freshwater invertebrateDaphnia magnahas been investigated and based on the geometric mean measured test concentration gave a 48-Hour EC50value of greater than 0.12 mg/L. The No Observed Effect Concentration was 0.12 mg/L.
This study showed that there were no toxic effects at saturation.