Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1999-01-25 to 1999-01-27
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
Age of test organisms: The test was started 25.5 hours after discarding of the young Daphnia from the breeding. Therefore it might be possible that some of hte test animals were slightly older than 24 hours. Presumed effect on the study: none
GLP compliance:
yes (incl. QA statement)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Tri (hexyl, octyl, decyl) citrate
- Substance type: pure active substance
- Physical state: liquid
- Stability under test conditions: in water for at least 2 hours
- Storage condition of test material: in original container, at room temperature, in the dark
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Melting point: -29°C (freezing point: -35.5°C)
- Boiling point: test substance showed decomposition above 260°C
- Vapour pressure: 8.5 x 10E-3 p at 25°C
- Water solubility (under test conditions): < 1 mg/L
- Solubility in organic solvents: soluble
- log Pow: > 6
- pKa: not applicable
- Base or acid catalysis of test material: no data
- UV absorption: no data
- Stability of test material at room temperature: stable
- pH dependance on stability: no data


OTHER PROPERTIES (if relevant for this endpoint)
- Adsorption characteristics: no data

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
In a pre-experiment (without GLP) the dissolved organic carbon contents (DOC) of the test substance solution (same preparation as in the test) was determined. In the solution the same amount of DOC was determined as in the blank control. Thus, no dissolved test substance could be verified in test water. Therefore, no analytical dose verification in the test media of the acute toxicity test with Daphnia could be done.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A supersaturated stock suspension of the test substance with a nominal concentration of 100 mg/L was prepared by weighing 503 mg of the test substance into 5 L test water, following ultrasonic treatment for 10 minutes and intense stirring. The supersaturated stock suspension was stirred on a magnetic stirrer at room temperauter in the dark over 3 days . Thereafter the suspension was filtered through a cellulose-nitrate filter with a defined pore size of 0.2 µm just before the start of the test.
- Controls: test water
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no, suspension was filtered

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Strain: Daphnia magna (Straus), clone 5
- Source: Umweltbundesamt, Institut for Wasser-, Boden- und Lufthygiene, Berlin, Germany
- Age at study initiation (mean and range, SD): 7 - 25.5 hours
- Method of breeding: under similar temperature and light conditions as in the test, and in reconstituted water of a similat quality regarding pH, components of the mian ions and total hardness as the test water used in the test, the test organisms were not first brood progeny
- Feeding during test: none


ACCLIMATION
- Acclimation period: 7 hours
- Acclimation conditions: same as test
- Type and amount of food: not fed
- Health during acclimation (any mortality observed): not mentioned

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
2.5 mmol/L (= 250.0 mg/L) as CaCO3
Test temperature:
21 °C
pH:
7.6 - 7.8
Dissolved oxygen:
7.6 - 8.9 mg/L
Salinity:
In deionized water (conductivity < 5 µS/cm) analytical grade salts were added to following nominal concentrations:
2.0 mmol/L (= 294 mg/L) CaCl2 x 2 H2O
0.5 mmol/L (= 123 mg/L) MgSO4 x 7 H2O
0.75 mmol/L (= 65.0 mg/L= NaHCO3
0.075 mmol/L =(= 5.8 mg/L) KCl
Nominal and measured concentrations:
WAF, no analytical determination of test substance concentration
Details on test conditions:
TEST SYSTEM
- Test vessel: Glass beakers of 100 mL volume with 50 mL test medium
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water
- Ca/mg ratio: 4:1 (based on molarity)
- Culture medium different from test medium: no
- Intervals of water quality measurement: not mentioned


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light
- Light intensity: 1178 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility or mortalitiy of the Daphnia was determined by visual controls after 24 and 48 hours. Measurement of pH, dissolved oxygen and water temperature at test start and end of test. The behaviour of the test substance in test water was determined at the start of the test, after 24 and 48 hours.
Reference substance (positive control):
yes
Remarks:
potassium dichromate, tested at least twice a year

Results and discussion

Details on results:
After 24 and 48 hours in the control and in the undiluted filtrate of the supersaturated stock suspension no mortality or immobilization of the test animals was observed.
No remarkable observations were made concerning the behaviour of the test substance in the filtrate.
Results with reference substance (positive control):
not mentioned
Reported statistics and error estimates:
The EC50 and EYC 100 could not be quantified due to the absence of toxicity of the test substance up to the water solubility

Any other information on results incl. tables

Table: Influence of test substance on the mobility of Daphnia magna

Treatment  No. of Daphnia tested  No. of immobilized Daphnia after         % of immobilized Daphnia after
    24 h   48 h  24 h  48 h
control   20  0  0  0  0
 filtrate of test substance  20  0  0  0  0

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Mortality of Daphnia magni in the control did not exceed 10 % and no Daphnia were trapped at the water surface.
Conclusions:
Due to low water solubility of the test substance a filtrate of a supersaturated stock suspension of nominal 100 mg/L was tested. Thus no concentrations above the solubility limit of the test substance in the used test water were tested. Due to the low water solubility limit no analytical dose verfication could be done in the present test. Therefore, the biological results could not be related to a specific concentration but to the solubility limit of Tri (hexyl, octyl, decyl) citrate in the test medium.
The 48-hour NOEC, respectively the 48-hour EC0 of the test substance to Daphnia magna were determined to be at least up to the solubility limit. The NOEC and the EC0 might even be higher, but concentrations in excess of the solubility limit had not been tested. The 48-hour EC50 was clearly higher than the solubility limit of the test substance in the used test water.
Executive summary:

Due to low water solubility of the test substance a filtrate of a supersaturated stock suspension of nominal 100 mg/L was tested. Thus no concentrations above the solubility limit of the test substance in the used test water were tested. Due to the low water solubility limit no analytical dose verfication could be done in the present test. Therefore, the biological results could not be related to a specific concentration but to the solubility limit of Tri (hexyl, octyl, decyl) citrate in the test medium.

The 48-hour NOEC, respectively the 48-hour EC0 of the test substance to Daphnia magna were determined to be at least up to the solubility limit. The NOEC and the EC0 might even be higher, but concentrations in excess of the solubility limit had not been tested. The 48-hour EC50 was clearly higher than the solubility limit of the test substance in the used test water.