Hexanoic acid, 3,5,5-trimethyl-, 1,1'-[2-ethyl-2-[[(3,5,5-trimethyl-1-oxohexyl)oxy]methyl]-1,3-propanediyl] ester

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 July 2013 - 13 January 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in accordance with recognised guidelines

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 or 100 mg/L nominal loading rate
- Sampling method:
- Sample storage conditions before analysis: The samples were stored frozen prior to analysis

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test material was prepared as a Water Accomodated Fraction. An amount of the test material (2100 mg) was added to the surface of 21 liters of test water to give the 100 mg/L loading rate. After the addition of the test material, the test 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 one hour. A wide bore glass tube, covered at on end with Nescofilm was submerged into the vessel, sealed end down, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal. Microscopic inspection of the WAF showed no micro-dispersions or undissolved test material to be present. The aqueous phase or WAF was removed by mid-depth siphoning (the first 75-100 mL was discarded) to give the 100 mg/L loading rate WAF.
- Eluate: Laboratory tap water dechlorinated and partly softened.
- Differential loading: not applicable
- Controls: Laboratory tap water dechlorinated and partly softened.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none

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, UK
- Age at study initiation: no data - juvenile
- Length at study termination (length definition, mean, range and SD): 4.2 +/- 0.4 cm
- Weight at study termination (mean and range, SD): 0.97 +/- 0.34 g
- Feeding during test: No


ACCLIMATION
- Acclimation period: 24 July to 05 August 2013 (12 days)
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: commercial trout pellets. No data on amount.
- Feeding frequency: No data
- Health during acclimation (any mortality observed): No mortality in the seven days prior to the start of the test

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

None

Hardness:

140 mg/L as CaCO3

Test temperature:

14-15 °C

pH:

7.9 - 8.1

Dissolved oxygen:

9.6 - 10.0 mg O2/L

Salinity:

Not applicable

Nominal and measured concentrations:

nominal concentrations: 0 or 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 L glass exposure vessel
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 20 L glass, no further details
- Aeration: yes, via narrow bore glass tubes.
- Renewal rate of test solution (frequency/flow rate): semi-static system - daily renewal
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): single vessel
- No. of vessels per control (replicates): single vessel
- Biomass loading rate: 0.34 g bw/L

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: 16 h light/ 8 h dark with 20 minute dawn and dusk transition periods
- Light intensity:no data

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

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 100 mg/L nminal loading rate
- Results used to determine the conditions for the definitive study:No effects noted in the range finding study

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

There were no mortalities in 7 fish exposed to a 100 mg/L loading rate WAF for a period of 96 hours.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

None

Sublethal observations / clinical signs:

Table 1: Cumulative mortality data in the definitive study.

Nominal loading rate (mg/L)	Cumulative mortality (n = 10)						% mortality
	3 h	6 h	24 h	48 h	72 h	96 h	96 h
Control	0	0	0	0	0	0	0
100	0	0	0	0	0	0	0

 

The test material concentration in the test samples was initially determined by gas chromatography (GC). Analysis of the control samples from the definitive test showed a peak was present, the profile of which was consistent with that of the test item.

Using this method of analysis, measured concentrations of between 0.0066 and 0.74 mg/L were obtained for the 100 mg/L loading rate WAF.

Given the presence of the peak in the control samples, a second analytical method was developed and the test material concentration in the duplicate test samples was determined by gas chromatography mass spectrometry (GC-MS) using an external standard. The test material gave a chromatographic profile consisting of a single peak and was developed so as to be a more specific method so as to identify the previously seen peaks. The GC-MS profile observed in the control samples was consistent with that of the test material; however it was assessed as a possible trace contaminant which had a similar profile to that of the test material. Given that no adverse effects were observed in the test, it was considered appropriate to correct the test results for the control.

Using this method of analysis, measured concentraions of between less than the concentration seen in the control and 0.60 mg/L were obtained for the 100 mg/L loading rate WAF.

Given that the toxicity cannot be attributed to a single component or a mixture of components, but to the test material as a whole, the results were based on nominal loading rates only.

Validity criteria fulfilled:

yes

Conclusions:

The 96-h LL50 based on nominal loading rates was > 100 mg/L loading rate WAF.

Executive summary:

Introduction

A study was performed under GLP to assess the acute toxicity of the test material to rainbow trout (Oncorhynchus mykiss). The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Regulation (EC) No. 440/2008.

Methods

Due to the low aqueous solubility and complex nature of the test item, for the purposes of the test the test medium was prepared as a Water Accommodated Fraction (WAF). Following a preliminary range-finding test, seven fish were exposed to a Water Accommodated Fraction (WAF) of the test material at a single nominal loading rate of 100 mg/L for a period of 96 hours at a temperature of 14 °C under semi-static conditions. the number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

Results

The test material concentration in the test samples was initially determined by gas chromatography (GC). Analysis of the control samples from the definitive test showed a peak was present, the profile of which was consistent with that of the test item.

Using this method of analysis, measured concentrations of between 0.0066 and 0.74 mg/L were obtained for the 100 mg/L loading rate WAF.

Given the presence of the peak in the control samples, a second analytical method was developed and the test material concentration in the duplicate test samples was determined by gas chromatography mass spectrometry (GC-MS) using an external standard. The test material gave a chromatographic profile consisting of a single peak and was developed so as to be a more specific method so as to identify the previously seen peaks. The GC-MS profile observed in the control samples was consistent with that of the test material; however it was assessed as a possible trace contaminant which had a similar profile to that of the test material. Given that no adverse effects were observed in the test, it was considered appropriate to correct the test results for the control.

Using this method of analysis, measured concentraions of between less than the concentration seen in the control and 0.60 mg/L were obtained for the 100 mg/L loading rate WAF.

Conclusion

Given that the toxicity cannot be attributed to a single component or a mixture of components, but to the test material as a whole, the results were based on nominal loading rates only. Exposure of rainbow trout to the test material gave LL50 values of > 100 mg/Lloading rate WAF. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF. It was considered unnecessary and unrealistic to test at loading rates in excess of 100 mg.L loading rate WAF.

Description of key information

One reliable study is available. In this study Rainbow trout (Oncorhynchus mykiss) were exposed to a Water Accommodated Fraction of the substance at a nominal loading rate of 100 mg/L under semi-static conditions for 96 hours. The LL50 (96 h) was > 100 mg/L loading rate WAF. The substance is not acutely harmful to fish.

Additional information

One reliable study is available. In this study (Parr, 2014) performed under GLP according to OECD TG 203 and EC Method C.1, Rainbow trout (Oncorhynchus mykiss) were exposed to the substance under semi-static conditions for 96 hours at a temperature of 14 °C. Due to the low aqueous solubility and complex nature of the test item, the test medium was prepared as a Water Accommodated Fraction (WAF). Following a preliminary range-finding test, seven fish were exposed to a WAF of the test material at a single nominal loading rate of 100 mg/L No mortality was observed during the study. The LL50 (96 h) value was > 100 mg/L loading rate WAF. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF.

 

The results of this study are supported by data available for the read-across substances Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (EC 234-392-1, CAS 11138-60-6)) and its analogues. The justification for read-across is presented in Section 13 Assessment reports- Read-across justification.

 

Two semi-static studies, investigating the short-term toxicity to freshwater fish of Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (CAS-No. 11138-60-6), are available. In the first study (Kuttler, 1998) performed according to OECD 203 and using Brachydanio rerio (Danio rerio) the LL50 (96 h) was > 10000 mg/L (WAF loading rate). In the second study (Källqvist and Tobiesen, 1995) with Salmo trutta according to OECD 203 the EC50 (96 h) was > 1000 mg/L and the LOEC > 1000 mg/L. As at the two highest concentrations (320 and 1000 mg/L) a small amount of emulsion and some increase in turbidity was observed, the highest concentration (1000 mg/L) demonstrated a worst case. In both studies no mortality was observed within the water solubility of the test substance under conditions tested. Therefore,it can be concluded that no toxicological effects on fish are expected up to the water solubility for Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (CAS-No. 11138-60-6).

 

There is one study, investigating the short-term toxicity to freshwater fish of Fatty acids, C5-10, esters with pentaerythritol (CAS-No. 68424-31-7). The semi-static study (Combert and Caunter, 1991) with Salmo gairdneri, similar to OECD 203, determined LC50 (96h) > 1000 mg/L (nominal). As the test material did not dissolve completely in the dilution water, the tested concentration demonstrated a worst case. No mortality was observed within the tested concentration (1000 mg/L nominal) during 96h exposure under conditions tested.