2,2-dimethyl-1,3-propanediyl didecanoate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 Sep - 20 Oct 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom, date of inspection: 10 July 2012

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Water samples were taken from the control, solvent control and the 100 % v/v test vessel at 0 (fresh media), 24 and 96 hours (old media) for quantitative analysis.
- Sample storage conditions before analysis: The 0 and 24 hour samples were stored at approximately -20 °C prior to analysis with the 96 hour samples. Duplicate samples and samples at 24 (fresh media), 48 and 72 hours (old and fresh media) were taken and stored at approximately -20 °C for further analysis if necessary.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
Pre-Study Media Preparation Trial:
1. Saturated Solution Preparation: An amount of test item (550 mg) was dispersed, in duplicate, in 11 liters of dechlorinated tap water with the aid of propeller stirring at approximately 1500 rpm for periods of either 24 or 48 hours. After stirring samples were taken for chemical analysis after the following pre-treatments:
- Centrifugation at 10000 g for 30 minutes
- Centrifugation at 40000 g for 30 minutes
- Filtration through a 0.2 μm Gelman Acrocap filter (approximately 100 mL discarded in order to pre-condition the filter)
- Filtration through a 0.2 μm Gelman Acrocap filter (approximately 500 mL discarded in order to pre-condition the filter)

2. Solvent Spike Preparation: An amount of test item (100 mg) was dissolved in dimethylformamide and the volume adjusted to 10 mL to give a 100 mg/10 mL solvent stock solution. An aliquot (500 μL) of this 100 mg/10 mL solvent stock solution was dispersed in 5 liters of dechlorinated tap water with the aid of magnetic stirring for approximately 10 minutes to give the required test concentration of 1.0 mg/L prior to taking samples for chemical analysis after the following pre-treatments:
- Centrifugation at 10,000 g for 30 minutes
- Centrifugation at 40,000 g for 30 minutes
- Filtration through a 0.2 μm Gelman Acrocap filter (approximately 100 mL discarded in order to pre-condition the filter)
- Filtration through a 0.2 μm Gelman Acrocap filter (approximately 500 mL discarded in order to pre-condition the filter)
The remainder of the 1.0 mg/L test concentration was returned to the magnetic stirrer and stirred for a further 48 hours with samples being taken for analysis after both 24 and 48 hours stirring.

The results obtained indicated that the use of a saturated solution method of preparation was inappropriate for this test item as measured concentrations far in excess of the predicted water solubility value of less than 0.050 mg/L were obtained. The results obtained from the solvent spike preparations indicated that the use of centrifugation was insufficient to ensure all undissolved test item was removed. Furthermore prolonged stirring of the solvent spike preparation was considered inappropriate as the test item appeared to be unstable. Based on this information the test item was prepared using a solvent spike method of preparation at an initial concentration of 1.0 mg/L, stirred for a approximately 10 minutes prior to the removal of any undissolved test item by filtration through a 0.2 μm Gelman Acrocap filter (first approximate 500 mL discarded).

Range-finding test:
An amount of test item (100 mg) was dissolved in dimethylformamide and the volume adjusted to 10 mL to give a 100 mg/10 mL solvent stock solution. An aliquot (2.0 mL) of this solvent stock solution was dispersed in 20 liters of dechlorinated tap water with the aid of magnetic stirring for approximately 10 minutes. After stirring any undissolved test item was removed by filtration through a 0.2 µm Sartorius Sartopore filter (first approximate 2 liters discarded in order to pre-condition the filter) to give the 100 % v/v solution of the test item. Aliquots of the 100 % v/v test concentration were then added to final volumes of 10 liters of dechlorinated tap water to give the further test concentrations of 1.0 and 10 % v/v. The test media was stirred using a flat-bladed mixer for approximately 1 minute to ensure homogeneity. The solvent stock solution was inverted several times to ensure adequate mixing and homogeneity. In the range-finding test 3 fish were added to each 10 liter test and control vessel and maintained at approximately 14 °C in a temperature controlled room with a photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods for a period of 96 hours under semi-static test conditions. The control and solvent control groups were maintained under identical conditions but not exposed to the test item. The solvent control group was exposed to 100 µL/L of dimethylformamide. Each vessel was covered to reduce evaporation. After 3, 6, 24, 48, 72 and 96 hours any mortalities or sub-lethal effects of exposure were determined by visual inspection of the test fish. A sample of each test concentration was taken for chemical analysis at 0 and 24 hours in order to determine the stability of the test item under test conditions. All samples were stored at approximately -20 °C prior to analysis. Only concentrations within the range to be used for the definitive test were analyzed.

Definitive test:
Based on the results of the range-finding test a "Limit test" was conducted at a concentration of 100 % v/v to confirm that at the highest attainable test concentration, no mortalities or sub-lethal effects of exposure were observed. For the purpose of the definitive test the test item was prepared using a preliminary solution in dimethylformamide. An amount of test item (100 mg) was dissolved in dimethylformamide and the volume adjusted to 10 mL to give a 100 mg/10 mL solvent stock solution. An aliquot (2.2 mL) of this solvent stock solution was dispersed in 22 liters of dechlorinated tap water with the aid of magnetic stirring for approximately 10 minutes. After stirring any undissolved test item was removed by filtration through a 0.2 µm Sartorius Sartopore filter (first approximate 2 liters discarded in order to pre-condition the filter) to give the required concentration of 100 % v/v. The test media was stirred using a flat-bladed mixer for approximately 1 minute to ensure homogeneity. The solvent stock solution was inverted several times to ensure adequate mixing and homogeneity. The concentration and stability of the test item in the test preparations were verified by chemical analysis at 0, 24 (old media) and 96 hours.
The control and solvent control groups were maintained under identical conditions but not exposed to the test item. The solvent control group was exposed to 100 µL/L of dimethylformamide.

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): dimethylformamide
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: Brow Well Fisheries Limited, Hebden, near Skipton, Yorkshire, UK and maintained in-house since 16 August 2012
- Feeding during test: no

ACCLIMATION
- Acclimation period: 12 September 2012 to 24 September 2012; Fish were maintained in a glass fiber tank with a "single pass" water renewal system. The water temperature was controlled at approximately 14 °C with a dissolved oxygen content of greater than or equal to 8.2 mg O2/L. These parameters were recorded daily.
- Acclimation conditions: same as test
- Type and amount of food: commercial trout pellets until 24 hours prior to the start of the definitive test. The diet is considered not to contain any contaminant.
- Health during acclimation (any mortality observed): There was no mortality in the 7 days prior to the start of the test and the fish had a mean standard length of 4.9 cm (sd = 0.2) and a mean weight of 1.46 g (sd = 0.29) at the end of the definitive test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

approximately 140 mg/L as CaCO3

Test temperature:

13 - 14 °C

pH:

7.6 - 8.2

Dissolved oxygen:

8.9 - 10.0 O2 mg/L

Nominal and measured concentrations:

range-finding test: control, solvent-control, 1.0, 10, and 100 % v/v (nominal)
definitive test: control, solvent-control, 100 % v/v (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: 20-L glass vessels (definitive test)
- Aeration: aerated via narrow bore glass tubes
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 7 (definitive test)
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.51 g bodyweight/liter (static volume)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water was dechlorinated by passage through an activated carbon filter (Purite Series 500) and partly softened (Elga Nimbus 1248D Duplex Water Softener) giving water with a total hardness of approximately 140 mg/L as CaCO3. After dechlorination and softening the water was passed through a series of computer controlled plate heat exchangers to achieve the required temperature.
- Total organic carbon: 0.92 mg/L
- Chlorine: 0.27 mg/L
- Intervals of water quality measurement: daily

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Any mortalities and sub-lethal effects of exposure were recorded at 3, 6, 24, 48, 72 and 96 hours after the start of exposure.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 1.0, 10, and 100 % v/v (nominal)
- Results used to determine the conditions for the definitive study: The results showed no mortalities at the test concentrations of 1.0, 10 and 100 % v/v. Based on this information, a single test concentration of 100 % v/v was selected for the definitive test. This experimental design conforms to a "Limit test" to confirm that at the highest attainable test concentration of 100 % v/v, no mortalities or sub-lethal effects of exposure were observed.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.086 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: highest attainable test concentration

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.086 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: highest attainable test concentration

Details on results:

- No mortality occurred during the study

Sublethal observations / clinical signs:

Range-finding test:

Chemical analysis of the 100% v/v test preparation at 0 hours showed a measured test concentration of 0.033 mg/L. A significant decline in measured test concentration was observed at 24 hours to less than the limit of quantitation (LOQ) of the analytical method employed which was determined to be 0.0045 mg/L. These results indicated that the test item was unstable over 24 hours.

Definitive test:

The test concentration of 100 % v/v was the highest attainable test concentration that could be prepared due to the limited solubility of the test item in water and having due regard to the amount of auxiliary solvent permitted in the study under the OECD Guidelines. At higher test concentrations there was a marked precipitation of the test item on addition of the solvent stock solution to water.

Chemical analysis of the 100% v/v solution at 0 and 72 hours (fresh media) showed measured concentrations of 0.037 and 0.039 mg/L were obtained respectively. A decline in measured test concentration was observed in the old or expired test media at 24 and 96 hours to less than the limit of quantitation (LOQ) of the analytical method employed, and 0.0086 mg/L respectively. This decline in concentration is considered to be due to the unstable nature of the test item. Current regulatory advice is that in cases where a decline in measured concentrations is observed, geometric mean measured concentrations should be used for calculating EC50 values. It was therefore considered justifiable to base the results on the geometric mean measured test concentrations in order to give a “worst case” analysis of the data. The time-weighted mean measured test concentration was determined to be 0.086 mg/L.

Table: Results for test samples:

Timepoint (hours)	Nominal Concentration of Test Item in Test Sample (nominal) (% v/v)	Measured Concentration of Test Item in Sample Vial (mg/L)	Sample Preparation Factor	Determined Concentration of Test Item in Test Sample (mg/L)
0 (fresh)	Control	<LOQ	0.1	<LOQ
	Solvent Control	<LOQ	0.1	<LOQ
	100	0.369	0.1	0.0369
24 (old)	Control	<LOQ	0.1	<LOQ
	Solvent Control	<LOQ	0.1	<LOQ
	100	<LOQ	0.1	<LOQ
72 (fresh)	100	0.394	0.1	0.0394
96 (old)	Control	<LOQ	0.1	<LOQ
	Solvent Control	<LOQ	0.1	<LOQ
	100	0.0863	0.1	0.00863

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes (incl. QA statement)

Remarks:

DEPARTMENT OF HEALTH OF THE GOVERNMENT OF THE UNITED KINGDOM, Derbyshire, UK

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control and 100 mg/L

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
An amount of test item (2100 mg) was added to the surface of 21 litres of dechlorinated tap water to give the 100 mg/L loading rate. After the addition of the test item, the dechlorinated tap water was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 23 hours and the mixture allowed to stand for 1 hour.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: obtained from Brow Weil Fisheries Limited, Yorkshire, UK and maintained in-house since 1 December 2011
- Age at study initiation (mean and range, SD): not reported
- Length at study initiation (length definition, mean, range and SD): 4.9 cm (sd = 0.4)
- Weight at study initiation (mean and range, SD): 1.43 g (sd = 0.32)
- Method of breeding: Fish were maintained in a giass fibre tank with a "single pass" water renewal system.
- Feeding during test: none


ACCLIMATION
- Acclimation period: 4 - 16 Jan 2012
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: commercial trout pellets
- Health during acclimation (any mortality observed): zero mortality in the 7 days prior to the start of the test

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

140 mg/L as CaCO3

Test temperature:

14 - 15 °C

pH:

7.9 - 8.3

Dissolved oxygen:

9.1 - 10.7

Nominal and measured concentrations:

Nominal: control and 100 mg/L
Measured (96h):

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): covered
- Material, size, headspace, fill volume: glass, 20 L
- Aeration: yes, via narrow bore glass tubes
- Renewal rate of test solution (frequency/flow rate): daily renewal
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.50 g body weight/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water was dechlorinated by passage through an activated carbon fflter (Purite Series 500) and partly softened (Elga Nimbus 1248D Duplex Water Softener)
- Total organic carbon: 0.92 mg/L
- Turbidity: 0.135 NTU
- Metals: Sb 0.531 μg/L; Cd 0.121 μg/L; Hg 0.018 μg/L; Ni 3.288 μg/L; others under detection limit
- Chlorine: 0.270 mg/L
- Conductivity: 315.000 μS/cm at 20 °C
- Culture medium different from test medium: no
- Intervals of water quality measurement: each 24 h

OTHER TEST CONDITIONS
- Photoperiod: photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Any martalities and sub-lethal effects af exposure were recorded at 3, 24, 48, 72 and 96 hours after the start of exposure.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: no mortalities

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

mortality (fish)

Details on results:

- No mortality or sublethal effects were observed
- Mortality of control: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: During the test the 100 mg/L loading rate was observed to be a clear, colourless solution.
- Effect concentrations exceeding solubility of substance in test medium: yes
- Given that toxicity cannot be attributed to a single component or a mixture of components but to the test item as a whole, and the dissolved test item was generally below the quantifiable limit of the analytical method, the resuits were based on nominal loading rates only.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Remarks:

Summary of available data used for the endpoint assessment of the target substance

Adequacy of study:

key study

Justification for type of information:

Please refer to the Analogue Justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

mortality (fish)

Remarks on result:

other: Source: CAS 85186-86-3, Oleon, 2012, Oncorhynchus mykiss, 96 h, RL1

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Source: CAS 68855-18-5, Croda, 2012, Oncorhynchus mykiss, 96 h, RL1

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.086 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: highest attainable test concentration

Remarks:

Source: CAS 68855-18-5, Croda, 2012, Oncorhynchus mykiss, 96 h, RL1

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.086 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: highest attainable test concentration

Remarks:

Source: CAS 68855-18-5, Croda, 2012, Oncorhynchus mykiss, 96 h, RL1

Conclusions:

No effects are expected up to the limit of water solubility.

Description of key information

LC50 (96 h) > 0.086 mg/L (measured, geometric mean; Oncorhynchus mykiss); no effects up to the limit of water solubility; read-across

LL50 (96 h) > 100 mg/L (nominal; Oncorhynchus mykiss); no effects up to the limit of water solubility; read-across

Additional information

There is no study available in which the short-term toxicity of Neopentyl glycol dicaprate (CAS No. 27841-06-1) to fish was assessed. Therefore, read-across to the structurally and chemically closely related source substances Fatty acids, C8-18 and C18-unsatd., esters with neopentyl glycol (CAS 85186-86-3) and Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS 68855-18-5) was performed in accordance with Regulation (EC) No 1907/2006 Annex XI, section 1.5 in order to fulfill the data requirements for this substance. The source substances are characterized by similar chemical structures and are therefore considered suitable representatives for the assessment of the short-term toxicity of the target substance to fish. A detailed read-across justification in provided in IUCLID section 13.

The study conducted with the source substance Fatty acids, C8-18 and C18-unsatd., esters with neopentyl glycol (CAS 85186-86-3) was performed under semi-static conditions and according to OECD guideline 203, using Oncorhynchus mykissas test organism. A 100 mg/L loading rate, prepared as Water Accommodated Fraction (WAF), was applied in a limit test. No mortality occurred in the control and the treatment during the 96 h exposure period. Hence, the LL50 (96 h) was determined as > 100 mg/L (WAF, nominal).

The study conducted with the source substance Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS 68855-18-5) was carried out under semi-static conditions using Oncorhynchus mykissas test organism. A 100 % v/v nominal test concentration was prepared in a limit test. No mortality occurred in the control and the treatment during the 96 h exposure period. Hence, the LC50 (96 h) was determined as > 0.086 mg/L (geometric mean – highest attainable test concentration). The NOEC was determined as ≥ 0.086 mg/L (geometric mean – highest attainable test concentration). Based on the available results from structurally related read-across substances (in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5) which are characterized by a similar ecotoxicological profile and comparable structure, it can be concluded that the target substance Neopentyl glycol dicaprate (CAS No. 27841-06-1) is not actuely toxic to fish.