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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:
From 05 November 2019 to 07 November 2019
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report date:
2019

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
resp. EU C.2
GLP compliance:
yes (incl. QA statement)
Remarks:
GLP certificate is included in the Study Report.

Test material

Constituent 1
Chemical structure
Reference substance name:
6-methylbenzotriazole
EC Number:
205-265-8
EC Name:
6-methylbenzotriazole
Cas Number:
136-85-6
Molecular formula:
C7H7N3
IUPAC Name:
6-methylbenzotriazole
Test material form:
solid
Specific details on test material used for the study:
Batch number: N6A3I
Expiry date: 04 August 2022

Sampling and analysis

Analytical monitoring:
not required

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: Berlin
- Food type: green algae (Desmodesmus subspicatus)


22 hours and 25 minutes before the start of the test, the adult animals were separated from the young. 0.5 hours before test start, the adults were caught with the help of a glass tube, and the newborn daphnia (age < 24h) were sieved from the medium and immediate-ly placed into a beaker containing dilution water. After the settling-in period, animals which showed no apparent damage were used for the test.
Switching from M4-medium (husbandry) to Dilution water (test) has been shown not to cause any detrimental effects for test daphnia, therefore no acclimation period of 48 h was performed. This is a deviation from OECD Guideline No. 202 and EU-Method C.2, which can be considered uncritical

Study design

Test type:
not specified
Water media type:
other: Dilution water (Daphnia medium) with the following specification was used : CaCl2*2H2O 293.80 mg/L; MgSO4*7H2O 123.30 mg/L; NaHCO3 64.80 mg/L; KCl 5.80 mg/L
Total exposure duration:
48 h

Test conditions

Test temperature:
19.3 - 20.4 °C
pH:
7.4 - 7.8
Dissolved oxygen:
8.5 - 8.8
Nominal and measured concentrations:
Nominal concentrations (mg/L):4.6; 10; 22; 46; 100
mesaured concentrations (mg/L, t=0h): 4.73; 10.42; 21.85; 44.86; 97.43
mesaured concentrations (mg/L, t=48h):5.18; 11.49; 24.31; 53.67; 111.22

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
LOEC
Effect conc.:
ca. 46 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
ca. 22 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
ca. 51.57 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
ca. 67.63 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L nominal concentration. After 48 hours the 2 highest concentrations 46 mg/L and 100 mg/L showed toxicity between 20 and 100% immobilisation. None of the animals was immobilised in the blank control and the lower concentrations.
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study to assure that the test conditions are reliable.
The analytical determinations of the test item showed good correlation between nominal and measured concentrations and good recovery rates. The measured concentrations at the beginning and at the end lay between 102 % and 105 % of the nominal concentra-tions.
Therefore, the determination of the results was based on the nominal concentrations (see Guidance Doc. No.23 (§176)).
No observations were made which might cause doubts concerning the validity of the study outcome. All validity criteria were met.
The result of the test is considered valid.
Results with reference substance (positive control):
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study to assure that the test conditions are reliable.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes