1,4-Benzenediol, 2-(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)-

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:

May-August 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

Acetone

Details on test solutions:

The solubility of the test item in M4 medium was determined as 2.07 mg/L. Therefore, a
stock solution containing 2.00 g/L in acetone was prepared. 250 μL of this stock solution
was mixed with 250 mL M4-medium for preparation of the test solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species Daphnia magna
Authority STRAUS
Strain Berlin
Sex female
Age between 0 and 24 hours
Origin Umweltbundesamt Berlin
In-house breeding since 27. September 2007

Test type:

semi-static

Water media type:

freshwater

Remarks:

Deionized water with an enrichment of certain minerals was used in the test. The minerals which are added comply to the composition M4

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Deionised water is used as base of M4

Test temperature:

20.1-20.9 oC

pH:

7.6-8

Dissolved oxygen:

8.6-8.8 mg/L

Nominal and measured concentrations:

nominal 2 mg/L
measured 0.14 mg/L

Details on test conditions:

Date of performance: 26. – 28. May 2021
Treatments: 2 mg/L (nominal concentration)
The concentrations to be tested are based on the result of
a non-GLP pre-test.
Temperature: 20.1 – 20.9 °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
Test vessels: glass beakers, nominal volume 50 mL, tall shape
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
Replicates Solvent Control: 4 vessels, each containing 20 ± 5 mL M4-medium spiked
with acetone and 5 daphnia

Reference substance (positive control):

yes

Remarks:

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 values lay within the range of the laboratory (1.20 – 2.82 mg/L).

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.14 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Remarks:

The test item is not stable under test conditions and poorly soluble in test medium. Although the concentrations of the test material are low, the daphnia were exposed to the hydrolytic product as the substance undergo fast hydrolysis in the study medium.

Basis for effect:

mortality

Details on results:

The study was performed as a limit test using the concentrations 2 mg/L nominal, because
the solubility of the test item in M4 medium was determined as 2.07 mg/L. Because the test
item is not stable under test conditions and poorly soluble in test medium, acetone was used
to spike the concentration to be tested. The concentration of the solvent was 1000-fold
higher than the nominal concentration in the treatment. For the solvent control, only acetone
in a concentration of 1 mL/L was used. For the test concentration and the blank control, 20
daphnia were exposed to the test item for 48 hours in a semi static test system. After 24 and
48 hours, the immobilised daphnia were counted.
None of the animals was immobilised in the controls and the tested concentration.

Results with reference substance (positive control):

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current
reference study (202105R201). The 24h-EC50 value was determined as 2.22 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

After 48 hours, none of the animals was immobilised in the controls and the tested concentration. A mean concentration of 2 mg/L of the tested substance was used in the study. However, the measured concentration was 0.14 mg/L due to instability of the substance in water.

Executive summary:

After 48 hours, none of the animals was immobilised in the controls and the tested concentration of 2 mg/L.

Description of key information

After 48 hours, none of the animals was immobilised in the controls and the tested concentration. A mean concentration of 2 mg/L of the tested substance was used in the study. However, the measured concentration was 0.14 mg/L due to instability of the substance in water.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 0.14 mg/L