Registration Dossier

Ecotoxicological information

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:
other: Study undertaken in GLP accredited laboratory.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report Date:
2001

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
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
- Analytical purity: Dipropylene glycol dibenzoate - 89.4% (w/w)
- Impurities (identity and concentrations):
Dipropylene glycol monobenzoate - 4.98% (w/w)
Propylene glycol dibenzoate - 2.29% (w/w)
Propylene glycol monobenzoate - 0.28% (w/w)
Propenyloxy propyl benzoate - 2.35% (w/w)
- Lot/batch No.: 56635211
- Expiration date of the lot/batch: 17 December 1997
- 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 concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EL50
Effect conc.:
43.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
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
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.