Oxydipropyl dibenzoate

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:

11 October 1997 - 13 October 1997.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Benzoflex 9-88

IUPAC Name:

Benzoflex 9-88

Constituent 2

Reference substance name:

Oxydipropyl dibenzoate

EC Number:

248-258-5

EC Name:

Oxydipropyl dibenzoate

Cas Number:

27138-31-4

Molecular formula:

C20H22O5

IUPAC Name:

oxydipropyl dibenzoate

Details on test material:

- Name of test material (as cited in study report): Benzoflex 9-88 (Dipropylene glycol dibenzoate DPGDB)
- Physical state: Clear colourless liquid
- Storage condition of test material: Room temperature

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: nominal loadings - 0 (control), 1.0, 2.2, 4.6, 10, 22, 46 and 100 mg/L
- Sampling method: Duplicate pooled medium samples were taken at 0 and 48 hours; sampling methodology not specified.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The method of preparation was selected following advice given in ECETOC 1996 Monograph No 26 as the test material has poor water solubility.
Test material was added by accurate pipette to 2 L glass vessels of Elendt M4 medium and stirred for at least 18 hours. Once stirred the solutions were left to stand for one hour prior to removing the water accommodated fraction. Approximately 800 mL of the solution was removed from a mid-water position.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): In preparation of the water accommodated fraction, when it was left to stand (without stirring), globules of test material were seen at the bottom of the vessels and a film was seen on the surface of the water. In the exposure vessels, expired solutions were noted to be cloudy after 24 hours.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: Cultured in-house from a strain originating from the Institute National de Recherche Chimique Applique (IRChA), France
- Age at study initiation (mean and range, SD): Less than 24 hours old
- Method of breeding: The Daphnia used were bred under conditions which ensures that cultures reproduce by parthenogenesis


ACCLIMATION
- Acclimation period: Not applicable - the Daphnia used were all less than 24 hours old. Stock culture conditions are provided below.
- Type and amount of food: A suspension of the unicellular green alga, Chlorella vulgaris

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Test temperature:

19 to 21°C

pH:

7.9 to 8.1

Dissolved oxygen:

7.0 to 8.0 mgO2 / L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal loadings(fresh) ; 0 (control), 1.0, 2.2, 4.6, 10.0, 22, 46 and 100 mg/L
Measured concentrations of dipropylene glycol dibenzoate (expressed as % of loading)
1.0 mg/L: 33.9 (Fresh prepared), 18.1 (expired / 48 hours old)
2.2 mg/L: 40.7, 27.3
4.6 mg/L: 30.8, 26.8
10 mg/L: 49.4, 26.6
22 mg/L: 40.3, 27.5
46 mg/L: 13.8, 9.2
100 mg/L: 19.3, 7.1
Measured concentrations for dipropylene glycol monobenzoate (expressed as % loading rate in terms of dipropylene glycol dibenzoate)
1.0 mg/L: 3.6 (Fresh prepared), 9.0 (expired / 48 hours old)
2.2 mg/L: 5.0, 13.7
4.6 mg/L: 5.2, 16.0
10 mg/L: 4.8, 18.2
22 mg/L: 5.8, 11.3
46 mg/L: 7.6, 8.3
100 mg/L: 13.9, 6.9

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type : closed ( loosely covered to minimise evaporative losses)
- Material, size, headspace, fill volume: 250 mL glass jars, filled with 200 mL test medium
- Renewal rate of test solution (frequency/flow rate): None (static test)
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 40 mL test solution per organism.


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4 medium, prepared in house using analytical reagents and deionised water

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light / 8 hours dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilisation


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

43.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

19.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limits : 13.1 - 28.5 mg/L

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

2.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 5% immobilisation was caused at 2.2 mg/L; this level of immobilisation is not considered significant.

Details on results:

- Mortality of control: Two Daphnia in the control level were immobilised after 48 hours. As this corresponded to the no-effect level of 10%, the study results were still considered valid.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Precipitation was observed, as noted previously. The analytical method used to confirm the concentration of test material in solution determined concentrations of dipropylene glycol monobenzoate DPGMB) as well as dipropylene glycol dibenzoate (DPGDB); the concentration of DPGDB was found to be lower after 48 hours than at the start of the test in all cases, whereas the concentration of DPGMB had generally increased. This observation suggests that the monobenzoate was a degradation product of the dibenzoate.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48 hour EL50 (immobilisation value for DPGDB with Daphnia magna) was determined to be 19.3 mg/L. The "no-observed effect loading rate" (NOELR) was 2.2 mg/L.

Executive summary:

An acute Daphnia Immobilisation study was performed to determine the actue toxicity to Daphnia of the test material dipropylene glycol dibenzoate (DPGDB). The study was conducted according to EC, OECD, and US EPA test guidelines, and in compliance with GLP.

The 48 hour EL50 (immobilisation value for DPGDB with Daphnia Magna) was determined to be 19.3 mg/L. The "no-observed effect loading rate" (NOELR) was 2.2 mg/L.