[No public or meaningful name is available]

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:

2022

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Principles of method if other than guideline:

This study was performed in order to evaluate the toxicity of the test item
tributyl(ethyl)phosphonium diphenyl phosphate in an acute immobilisation test under static
conditions towards Daphnia magna. Daphnia magna STRAUS, was chosen in the guideline
as a typical species of zoo-plankton.
Young daphnia, aged less than 24 hours at the start of the test, were exposed to the test
item for a period of 48 hours. Immobilisation was recorded at 24 hours and 48 hours and
compared with control values. Not more than 10 % of the control daphnia should show immobilisation or other signs of disease or stress, for example, discoloration or unusual behaviour such as trapping at surface of water. The results were analysed in order to calculate
the EC50 at 48 h.
A positive control was tested in a separate study to assure that the test conditions are reliable.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Tributyl(ethyl)phosphonium diphenyl phosphate

Cas Number:

2409816-82-4

Molecular formula:

C26H42O4P2

IUPAC Name:

Tributyl(ethyl)phosphonium diphenyl phosphate

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

not specified

Remarks:

An analytical method for the determination of tributyl(ethyl)phosphonium diphenyl phosphate using IC was validated.

Details on sampling:

The 46 mg/L test item solutions were diluted as follows:
250 µL of 46 mg/L solution were mixed with 750 µL demineralised water resulting in a
4fold dilution. The lower tested concentrations were measured undiluted.

Test solutions

Vehicle:

not specified

Details on test solutions:

The concentration of the test item in the test solutions was determined as follows:
Linear calibration curve:
cmeasured [mg/L] = 【(Measured value - a)/b * 】*【100 %/
QC Recovery Rate [%] 】∗【 dilution factor】
with
a = intercept
b = slope

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

18.5 hours 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 immediately placed into a beaker
containing M4 medium. After the settling-in period, animals which showed no apparent damage were used for the test.

Study design

Test type:

not specified

Water media type:

other: Deionized water with an enrichment of certain minerals was used in the test.

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

Duration: 48 hours
Observation times: 24 and 48 hours

Test conditions

Test temperature:

Temperature: 19.4 – 20.3 °C
within one test, temperature did not vary more than 2 °C

Details on test conditions:

Treatments: 1 / 2.2 / 4.6 / 10 / 22 / 46 mg/L (nominal concentration)
The concentrations to be tested were based on the result of
a non-GLP pre-test.
Temperature: 19.4 – 20.3 °C
within one test, temperature did not vary more than 2 °C
Photo period: 16/8 hours, using LED’s
Duration: 48 hours
Observation times: 24 and 48 hours
Medium renewal: none
Replicates (Treatments): 4 vessels, each containing 20 ± 5 mL test solution and 5
daphnia
Replicates (Blank control): 4 vessels, each containing 20 ± 5 mL M4 medium and 5
daphnia

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 13.13 mg/L

95% CI:

>= 10.29 - <= 16.8

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Any other information on results incl. tables

The estimation of the biological result was accomplished using the software ToxRat® Professional, version 3.3.0. The details of calculation are stated in the Annex 5: Statistical calculation using ToxRat® Professional 3.3.0.
The four highest tested concentrations showed toxicity between 5 and 100 % immobilization
after 48 hours. None of the animals were immobilised in the blank control.
The concentrations determined at the start of the test were in a range between 97 and 101 %
of the nominal concentration. At the end of the test the determined concentrations were
between 102 and 107 % of the nominal concentration. Therefore, the determination of the
biological results was based on the nominal concentration (see Guidance Doc. No.23
(§176)).
The biological results are presented in the following table:
Table 9 Biological Result of the Test Item
Parameter                      Value                    95%-confidence interval
48h EC50                       13.13                    10.29 – 16.80

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

All validity criteria were fulfilled:  Immobilisation in the controls may not exceed 10 %. Immobilisation in the control was 0 %.  The concentration of dissolved oxygen at the end of the test must be at least 3 mg/L. The lowest concentration of dissolv

Conclusions:

The following result was determined for the test item tributyl(ethyl)phosphonium diphenyl
phosphate (species: Daphnia magna).
48h-EC50 = 13.13 mg/L (nominal)

Executive summary:

The study was performed using 6 concentrations ranging from 1 to 46 mg/L nominal concentration. For each test concentration and the blank control, 20 daphnia were exposed to
the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised
daphnia were counted.
The four highest tested concentrations showed toxicity between 5 and 100 % immobilization
after 48 hours. None of the animals were immobilised in the blank control.
3,5-Dichlorphenol (C6H4Cl2O, CAS No. 591-35-5) was used as positive control in a current
reference study to assure that the test conditions are reliable.
At the beginning and at the end of the test, the content of the test item in the test solutions
was determined using IC determination. The concentrations determined at the start of the
test were in a range between 97 and 101 % of the nominal concentration. At the end of the
test the determined concentrations were between 102 and 107 % of the nominal concentration. Therefore, the determination of the biological results was based on the nominal concentration (see Guidance Doc. No.23 (§176)).
The following result was determined for the test item tributyl(ethyl)phosphonium diphenyl
phosphate (species: Daphnia magna).
48h-EC50 = 13.13 mg/L (nominal)