Reaction mass of 2-[[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]methyl]oxirane and 1,3-bis[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]propan-2-ol and 1-[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]-3-[4-[[4-[3-[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]-2-hydroxy-propoxy]-3,5-dimethyl-phenyl]methyl]-2,6-dimethyl-phenoxy]propan-2-ol

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The test substance was added without a carrier solvent to dilution medium at the highest treatment level. This was then stirred for up to 4 hours, and the remaining concentrations prepared by serial dilution. The reported solubility of the test substance was incorrectly stated as 46.13 mg/L.
A reliable water solubility test has shown this to be much lower (1.26 mg/L).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: Original source organisms from Aquatic Biosystems in Fort Collins, CO (Annual taxinomic verification provided).
- Age at study initiation: < 24 hours old (released within 8 hours of each other).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Moderately hard re-constituted water with a hardness value of 98 mg/L as CaCO3

Test temperature:

20°C +/- 2°C

pH:

Dilution medium pH value of 8.1

Dissolved oxygen:

Dilution medium DO value of 7.9 mg/L

Nominal and measured concentrations:

Definitive phase: 0 (control), 2.83, 5.67, 11.25, 22.5 and 45 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 35 mL Nalgene cups
- Type: open
- Material, size, headspace, fill volume: 25 mL (fill volume)
- Aeration: No data
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Moderately hard re-constituted water formulated from deionised water produced from E-Pure deionization system that is amended with reagent grade chemicals following EPA's Acute Whole Effluent Toxicity Test Methods.
- Total organic carbon: < 1.0 mg/L
- Chlorine: < 0.01 mg/L
- Alkalinity: 72 mg/L as CaCO3
- Conductivity: 341 umhos/cm

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light, 8 hours darkness
- Light intensity: 10-20 μE/m2/s (50-100 ft-c).

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Significant mortality at 24 and 48 hours

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0, 0.01, 0.1, 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study

Reference substance (positive control):

yes

Remarks:

Sodium Chloride

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.021 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: based on statistical expolation

Details on results:

As the test substance is the major component of the registered substance, which being the most bioavailable; the bioavailability of this component within the registered substance can be expected to be reduced as it is chemically bound to dimers, trimers and oligomers. Based on statistical expolation of the results, EC50 was determined to be 2.021 mg/l. It was stated in the report that this value is lower than the limit of solubility which was 46.13 mg/l therefore showing toxicity at concentration less than the solubility of the test material. However, this value exceeded the limit of water solubility determine for this substance (1.26 mg/l) and therefore it is expected that the registered substance to be within this range.

Observation of the test solutions indicated that the substance was not fully dissolved and therefore may have led the Daphnia being exposed to concentration lower than the true limit of water solubility of this substance so this result need to be treated with caution.

Results with reference substance (positive control):

- Results with reference substance within acceptable laboratory range
- EC50: 4.889 g/mL

Reported statistics and error estimates:

A linear interpolation method was used to calculate the point estimates. Statistical analysis conducted using Steel Many-One rank Test at 24 and 48 hours.

Validity criteria fulfilled:

yes

Remarks:

No control mortality observed.

Conclusions:

In a 48 hr acute toxicity study, the 48hr EC50 value was determined 2.021 mg/L by statistical expolation.

Description of key information

In a 48hr acute toxicity study, Daphnia magna were exposed to the test substance at measured concentrations of 0 (control), 2.83, 5.67, 11.25, 22.5 and 45 mg/L (nominal) under semi-static conditions. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.021 mg/L

Additional information

As the test substance is the major component of the registered substance, which being the most bioavailable; the bioavailability of this component within the registered substance can be expected to be reduced as it is chemically bound to dimers, trimers and oligomers. Based on statistical expolation of the results, the EC50 was determined to be 2.021 mg/l. It was stated in the report that this value is lower than the limit of solubility which was 46.13 mg/l therefore showing toxicity at concentration less than the solubility of the test material. However, this value exceeded the limit of water solubility determine for this substance (1.26 mg/L) and therefore it is expected that the registered substance to be within this range.