Diundecyl phthalate

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:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

equivalent or similar to guideline

Guideline:

other: EPA-660/3-75-009

Version / remarks:

(Methods for acute toxicity tests with fish, macroinvertebrates, and amphibians)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Up to 0.02 mg/L (not specified how many concentrations used)
- Sampling method: all test solutions and control test water were analyzed at 0 h and on the last day of the study. In addition, two quality-assurance samples were prepared on each sample collection day and remained with the set of samples through the extraction and analysis procedures. These two samples were prepared in test water or media, with one of the samples prepared at a concentration unknown to the analyst.
The stock solution prepared for each test concentration was sampled in duplicate before it was poured into the test vessels.
At the end of the study, replicate test solutions were combined and duplicate samples were analyzed.
- Sample storage conditions before analysis: sample extracts were stored in a 10-ml serum vial at 0°C until the analysis was performed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
No data

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: waterflea
- Source: no info
- Age of parental stock (mean and range, SD): no data

ACCLIMATION
- Acclimation period: minimum 48 h
- Acclimation conditions (same as test or not): appropiate temperature before being tested
- Health during acclimation (any mortality observed): Mortality never exceeded 1.0 % in a 48-h period prior to test initiation.

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

25 to 50 mg CaCO3/L

Test temperature:

20 ± 1ºC (maintained by a temperature-controlled waterbath)

pH:

7.6-7.9

Nominal and measured concentrations:

Highest mean measured concentration: 0.02 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass jar
- Material, size, headspace, fill volume: glass
- Renewal rate of test solution (frequency/flow rate): No, static test
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): Not specified
- No. of vessels per vehicle control (replicates): N/A
- Biomass loading rate: Not specified

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Not specified
- Alkalinity: 25 to 50 mg CaCO3/L
- Intervals of water quality measurement: Dissolved oxygen and pH were measured at all observation periods (0, 24 and 48 h) in all test vessels. Temperature was measured at the same intervals but only in the control vessels.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Acute no-observed-effect concentrations (NOECs) were determined operationally at the end of each test by selecting the highest test concentration at which 10% or less immobilization occurred.
This provided a value that was somewhat analogous to an EC10. When ≤10 % immobilization was observed at all test concentrations the NOEC was reported as the highest concentration tested. Behavioral observations were not used to determine the NOEC.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Not specified
- Range finding study
- Results used to determine the conditions for the definitive study: Not specified for DUP, only the general procedure was reported: If the range-finding test indicated that toxicity would occur at a concentration below the water solubility of the test chemical, definitive test was done using five concentrations and a control. If the range-finding test indicated that no toxicity would occur at levels up to the water solubility of the chemical, a test with a single concentration was performed at or near the water-solubility limit of the chemical.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.02 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Insufficient immobilization observed at the highest test concentration (value shown) to calculate an acute toxicity value.

Details on results:

It was not possible to calculate acute no-observed-effect concentrations (NOECs) or EC50 values because of a lack of immobilization. The acute NOEC was observed to be higher than the highest concentration tested as less than 10% immobilization was observed.
The report stated that phthalate esters with alkyl chain lengths of six carbon atoms or more were not acutely toxic at concentrations up to their respective aqueous solubilities (≤ 1.1 mg/L).

Results with reference substance (positive control):

Not applicable

Validity criteria fulfilled:

yes

Conclusions:

In a short-term toxicity test to daphnia magna conducted in static conditions, the 48h-EC50 of the test substance was found to be higher than 0.02 mg/L based on no immobilization observed at any concentrations tested.

Executive summary:

An acute aquatic toxicity study with daphnia magna was conducted for DUP following methods for Acute Toxicity Tests with Fish, Macroinvertebrates, and Amphibians (EPA-660/3-75-009), OECD guidelines and EPA GLP. A preliminary range finding study was performed to determine the concentrations used in the main test. The main test was conducted with test concentrations up to 0.02 mg/L for a period of 48 h in static conditions with ten organisms in each group, including a control test. A validated analytical method based on gas chromatography was used to monitor the concentration of DUP in the test solutions at 0 h and at the end of the study. It was not possible to calculate the NOEC or EC50 because of a lack of immobilization. The acute NOEC was observed to be higher than the highest concentration tested as less than 10% immobilization was observed. Based on these results, the 48h-EC50 of the test substance is reported to be higher than 0.02 mg/L.

Description of key information

Key study. Test method according to US EPA (1975): "Methods for acute toxicity tests with fish, macroinvertebrates and amphibiens", OECD guidelines and EPA GLP. DUP was tested with

Daphnia magna in static conditions at concentrations up to 0.02 mg/L. No immobilization was observed at any concentrations tested. Thus, the 48h-EC50 was determined to be higher than 0.02 mg/L. Furthermore, due to the very low water solubility, no acute aquatic toxicity is expected at concentrations up to the water solubility of the test substance.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.02 mg/L

Additional information

Key study. An acute aquatic toxicity study with daphnia magna was conducted for DUP following methods for Acute Toxicity Tests with Fish, Macroinvertebrates, and Amphibians (EPA-660/3-75-009), OECD guidelines and EPA GLP. A preliminary range finding study was performed to determine the concentrations used in the main test. The main test was conducted with test concentrations up to 0.02 mg/L for a period of 48 h in static conditions with ten organisms in each group, including a control test. A validated analytical method based on gas chromatography was used to monitor the concentration of DUP in the test solutions at 0 h and at the end of the study. It was not possible to calculate the NOEC or EC50 because of a lack of immobilization. The acute NOEC was observed to be higher than the highest concentration tested as less than 10% immobilization was observed. Based on these results, the 48h-EC50 of the test substance is reported to be higher than 0.02 mg/L. Furthermore, the study report concluded that phthalate esters with alkyl chain lengths of six carbon atoms or more were not acutely toxic at concentrations up to their respective aqueous solubilities.