2,4,8,10-tetra(tert-butyl)-6-hydoroxy-12H-dibenzo[d,g] [1,3,2]dioxaphosphocin, 6-oxide

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:

From 2017-11-08 to 2017-11-10

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)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Purity: > 99%
Batch No.: 101Z4

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test sample 0.0500 g and dilution water 500 mL were mixed to prepare the nominal concentration of 100 mg/L, and they were stirred with a magnetic stirrer for 48 hours at about 20 °C. Total three suspensions were made in above same manner. Then, these suspension were filtered with a glass fiber filter by suction, and all filtrate were mixed. The mixed filtrate was stirred for 30 minutes at about 20 °C, then used as the stock solution.
- Controls: Dilution water processing similar to stock solution without the test item

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Daphnia magna Clone A
- Source: The University of Sheffield, UK
- Age of parental stock (mean and range, SD): 14-day old
- Feeding during test: No feeding

ACCLIMATION
- Acclimation period:
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: Chlorella vulgaris of 0.1-0.2 mgC (Organic carbon content)
- Feeding frequency: once a day
- Health during acclimation (any mortality observed): survival rate: 100%

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

32 mg/L (Ca, Mg)

Test temperature:

20.0-20.2 °C

pH:

7.5-7.8

Dissolved oxygen:

7.3-8.8 mg/L

Nominal and measured concentrations:

Nominal: stock solution content of 100, 50.0, 25.0, 12.5 and 6.25%
Measured: 77.6, 38.4, 18.9, 9.17 and 4.57 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beaker
- Aeration: No
- No. of organisms per vessel: 5 daphnia / test vessel
- No. of vessels per concentration (replicates): 4 replicates / test level
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Total organic carbon: < 0.5 mg/L
- Alkalinity: 36 mg/L
- Conductivity: 13 mS/m

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Room light, 16-hour light / 8-hour dark

RANGE-FINDING STUDY
- Test concentrations: 5.00, 10.0, 50.0, 100% stock solution content and a control
- Results used to determine the conditions for the definitive study: The immobilization was 10%, 40% in 100% stock solution content at 24 and 48 hours, respectively.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

54.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confìdence limits: 43.8-75.2 mg/L

Details on results:

- Other adverse effects control: one daphnid showed immobilization (5%). However, other daphnids did not show any abnormal response (discolor of body, trapping at the surface of the water and so on)
- Abnormal responses: Observed abnormal responses during exposure were immobilization, lethargic and reduced activity.
- Observation and measurement of test solution:
The test solution in the exposure level and the control were colorless and clear at the start and end of exposure.
The measured concentrations of the test item in the test solutions at the start of exposure were 4.48-78.1 mg/L, and those at the end of exposure were 4.66-77.1 mg/L which were 98.6% of the concentrations at the start of exposure.
- Immobility: The minimum concentration causing 100% immobility at 48 hours was >77.6 mg/L, because it was not obtained from the concentration range in the definitive study. Maximum concentration causing no immobility at 48 hours was 9.17 mg/L.

Results with reference substance (positive control):

The 48-hour EC50 of a reference substance with the test organisms was 0.12 mg/L. This value was within the stipulated range (mean ± 2S.D.) [mean ± S.D.: 0 .23 ± 0.06 mg/L (n= 102)] to background data in this laboratory.

Validity criteria fulfilled:

yes

Conclusions:

The 24-hour and 48-hour EC50 of the test item for Daphnia magna were > 77.6 mg/L and 54.6 mg/L (95% confidence limits: 43.8-75.2 mg/L), respectively.

Executive summary:

The objective of this study is to determine the 48-hour median effective concentration (EC50) by conducting an acute immobilization study of the test item in Daphnia magna according to OECD Guideline 202.

Five test concentrations of 100, 50.0, 25.0, 12.5, 6.25% as stock solution content (a geometric series with a factor of 2.0) (77.6, 38.4, 18.9, 9.17, 4.57 mg/L as measured concentrations) and a control were prepared. Daphnia were exposed to the test solutions of these concentrations for 48 h.

 

The minimum concentration causing 100% immobility at 48 hours was > 77.6 mg/L, because it was not obtained from the concentration range in the definitive study. Maximum concentration causing no immobility at 48 hours was 9.17 mg/L. Immobility in the control during exposure was 5%. Observed abnormal responses during exposure were immobilization, lethargic and reduced activity. In the control, one daphnid showed immobilization (5%). However, other daphnids did not show any abnormal response (discolor of body, trapping at the surface of the water and so on).

The measured concentrations of the test item in the test solutions at the start of exposure were 4.48-78.1 mg/L, and those at the end of exposure were 4.66-77.1 mg/L which were 98.6% of the concentrations at the start of exposure.

 

The 24-hour and 48-hour EC50 of the test item for Daphnia magna were >77.6 mg/L and 54.6 mg/L (95% confidence limits: 43.8-75.2 mg/L), respectively.

Description of key information

The 24-hour and 48-hour EC50 of the test item for Daphnia magna were > 77.6 mg/L and 54.6 mg/L (95% confidence limits: 43.8-75.2 mg/L), respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

54.6 mg/L

Additional information

The objective of this study is to determine the 48-hour median effective concentration (EC50) by conducting an acute immobilization study of the test item in Daphnia magna according to OECD Guideline 202.

Five test concentrations of 100, 50.0, 25.0, 12.5, 6.25% as stock solution content (a geometric series with a factor of 2.0) (77.6, 38.4, 18.9, 9.17, 4.57 mg/L as measured concentrations) and a control were prepared. Daphnia were exposed to the test solutions of these concentrations for 48 h.

 

The minimum concentration causing 100% immobility at 48 hours was > 77.6 mg/L, because it was not obtained from the concentration range in the definitive study. Maximum concentration causing no immobility at 48 hours was 9.17 mg/L. Immobility in the control during exposure was 5%. Observed abnormal responses during exposure were immobilization, lethargic and reduced activity. In the control, one daphnid showed immobilization (5%). However, other daphnids did not show any abnormal response (discolor of body, trapping at the surface of the water and so on).

The measured concentrations of the test item in the test solutions at the start of exposure were 4.48-78.1 mg/L, and those at the end of exposure were 4.66-77.1 mg/L which were 98.6% of the concentrations at the start of exposure.

 

The 24-hour and 48-hour EC50 of the test item for Daphnia magna were >77.6 mg/L and 54.6 mg/L (95% confidence limits: 43.8-75.2 mg/L), respectively.