Sodium 3,5,5-trimethylhexanoate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2 August 2017 to 20 June 2018

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Batch number: 5764BF17
Purity: 44-46%
Expiry: 1 July 2019 (Re-test)

Analytical monitoring:

yes

Details on sampling:

Duplicate samples were taken at the start and end of the 48 hour exposure period. Samples were taken from remaining test media after filling test vessels for 0 hours and pooled replicate vessels for 48 hours.

Vehicle:

no

Details on test solutions:

Stock solutions were prepared for both the range-finding and definitive tests by addition of the test sample directly to Elendt M4 medium in a volumetric flask of adequate volume. Calculated volumes of the stock solution were added to Elendt M4 medium and made to volume to prepare the test concentrations and provide enough solution for testing and subsequent water quality measurements.
The test concentrations for both the range-finding test and definitive test were prepared separately by the addition of the test sample to Elendt M4 medium in volumetric flasks of adequate volume to provide enough solution for testing (25 mL) and subsequent water quality measurements.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna
Source: From cultures maintained at Chemex Environmental International Ltd since July 2014 and originally sourced from a clone of genotype 5.
Date of gravid isolation: 23 April 2018
Age of Daphnia at start of test: ≤ 24 hours
Culture conditions: Cultured under static conditions
Temperature: 20 ± 2°C
Dissolved oxygen: >60% (or 3mg/l) ASV
Photoperiod: 16 hours light and 8 hours dark
Feeding regime: Each working day, a suspension of Chlorella vulgaris. The Daphnia in the test were not fed.

The Daphnia were cultured, and the tests performed, in Elendt M4 media. The dissolved oxygen (DO) concentration was >60% or 3mg/l air saturation and the pH stabilised between 6 and 9 before commencement of the test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

Temperature range within incubator throughout test: 19.9 – 20.7 °C (Required: 20±2°C maintained to ±1°C)

pH:

Initial pH at 0 Hours: 7.97 pH range in control and test concentrations throughout test: 7.41 – 7.56

Dissolved oxygen:

Initial Dissolved Oxygen at 0 Hours: 9.89mg/l DO range in control and test concentrations throughout test: 8.83 – 9.89mg/l (Required: ≥3mg/l)

Nominal and measured concentrations:

The recovered concentrations at 0 and 48 hours were found to be within ±20% of nominal concentration therefore were reported as nominal.

Details on test conditions:

Illumination: 16 Hours Light, 8 Hours Dark Cycle

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Results with reference substance (positive control):

A separate GLP study (ENV 11395) was conducted from 18 to 20 January 2017 to monitor the sensitivity of the test animals and test procedures. The reference study gave a 24 hour EC50 of 1.4mg/l of potassium dichromate which was within the acceptable range 0.6 mg/l to 2.1 mg/l as specified in Technical Corrigendum to ISO6341.

Cumulative immobilisation

Active ingredient (mg/L)	% Immobilisation
	24 Hours	48 Hours
0 (Control)	0	0
100	0	0

Average recoveries of Isononanoic acid, sodium salt (1:1) (mg/l), percentage recovery compared to nominal concentrations.

Percentage recoveries of Isononanoic acid, sodium salt (1:1)
Nominal concentration of Sodium mg/L	Exposure period
	0 hours	48 hours	Mean measured
100	95.309%	97.743%	96.526%

Validity criteria fulfilled:

yes

Conclusions:

The Daphnia were examined at 24-hours and 48-hours for abnormal behaviour during the determination of immobility. All Daphnia appeared normal with no signs of abnormality.
The 24-hour EC50 and 48-hour EC50 of Isononanoic acid, sodium salt (1:1) to Daphnia magna were both >100mg/l (determined by direct observation)
The 0 to 24-hour NOEC and LOEC were 100mg/l and >100mg/l respectively (determined by direct observation).
The 0 to 48-hour NOEC and LOEC were 100mg/l and >100mg/l respectively (determined by direct observation).

Executive summary:

EC50>100 mg/L

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: Potassium 3,5,5-trimethylhexanoate
CAS No.: 93918-10-6
Batch No.: PURS151015
Purity: 99.4%
Physical State: solid
Colour: white
Molecular Weight: 196.33 g/mol
Storage Conditions: room temperature
Re-certification Date: 14 October 2016

Analytical monitoring:

yes

Details on sampling:

TOC analysis
A static test design was applied with an accompanying TOC-analysis. The swimming capability of the daphnids was assessed after 24 h and 48 h exposure. Samples of 5 mL were taken from each additional vessel for TOC-analysis (without test organisms in order to not disturb the TOC-analysis) of the test item treatment and NC at 0 h, 24 h and 48 h. Of these 4 samples per treatment and time, 2 were measured directly after sampling using a TOC-analyser and 2 samples were stored as retain samples in the freezer at ≤ -18 °C until finalization of the study.

Vehicle:

yes

Details on test solutions:

The test was performed with M4 medium according to OECD 202 (2004).

Test organisms (species):

Daphnia magna

Details on test organisms:

The test organism Daphnia magna Straus originates from the clone breeding of the Federal Environment Agency, department IV 2.4, Berlin, and has been cultivated at Hydrotox GmbH since October 2012. The daphnids are cultured at 20 ± 2 °C with 16 h light : 8 h dark and placed into fresh M4 medium twice a week. They are kept at approx. 10 animals / 200 mL and fed on workdays with Desmodesmus subspicatus algae corresponding to 0.1 mg C × daphnid-1 × day-1. The test organisms used were 0.25 - 22.5 h old at the start of the test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

The test was performed with M4 medium according to OECD 202 (2004).

Test temperature:

19.7 - 21.1 °C

pH:

The pH was 7.4 - 7.9 in the control and 7.6 - 7.9 in the test item treatment.

Dissolved oxygen:

The dissolved oxygen concentration was 7.8 - 8.2 mg/L in the control and 7.7 - 8.2 mg/L in the test item treatment.

Salinity:

Salinity of M4 medium.

Conductivity:

The test was performed with M4 medium according to OECD 202 (2004).

Nominal and measured concentrations:

The measured TOC-concentrations in the test item treatment were 89.0 – 91.2 % of the nominal concentrations and stable during the exposure period. The TOC-concentrations in the control were below the limit of quantification

Reference substance (positive control):

yes

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Results with reference substance (positive control):

Quality assurance takes place at regular intervals by testing the sensitivity of the test organisms to the potassium dichromate. The recent quality testing was performed in December 2015 with EC50 (24h) = 1.30 mg/L and EC50 (48h) < 1.25 mg/L.

The purpose of this study was to investigate the effects of the test item on Daphnia magna. Daphnids, less than 24 h old, were exposed to one concentration of the test item in M4 medium mfor 48 h. A static test design was applied with an accompanying TOC-analysis. The swimming mcapability of the daphnids was assessed after 24 h and 48 h exposure. A preliminary test without GLP was performed before start of this GLP-study. Nominal concentrations of 10, 40 and 160 mg/L test item were tested and showed no effects on the mobility of the test organisms. In the present study, a single concentration of 100 mg/L test item was used (limit test).

The test vessels were kept in an incubator with 16 h light : 8 h dark for 48 h. The swimming capability of the daphnids was determined after 24 h and 48 h exposure. Animals that did not swim within 15 s after gently moving the test vessel were considered to be immobile. The pH as well as the O2-concentrations were measured at the start (0 h) and at the end of the test (48 h) and the temperature was measured continuously.

The effect occurrence after 24 h and 48 h exposure was calculated. With the statistical software ToxRat Professional 3.2.1 (ToxRat Solutions GmbH, Alsdorf, Germany), LOEC/NOEC were determined.

Nominal test item concentration [mg/l]	Immobility [%]
	24 h	48 h
Negative control	0	0
100	10	15

Validity criteria fulfilled:

yes

Conclusions:

A static Daphnia magna acute immobilisation test was performed using a single concentration of 100 mg/L test item. All results are given in relation to nominal test item concentrations: NOEC >= 100 mg/l and LOEC > 100 mg/l.

Executive summary:

A static Daphnia magna acute immobilisation test was performed using a single concentration of 100 mg/L test item. All results are given in relation to nominal test item concentrations. NOEC was determined to be >= 100 mg/l and LOEC to be > 100 mg/l. The measured TOC-concentrations in the test item treatment were 89.0 – 91.2 % of the nominal

concentrations and stable during the exposure period. The TOC-concentrations in the control

were below the limit of quantification.

Description of key information

The Daphnia were examined at 24-hours and 48-hours for abnormal behaviour during the determination of immobility. All Daphnia appeared normal with no signs of abnormality.

The 24-hour EC50 and 48-hour EC50 of Isononanoic acid, sodium salt (1:1) to Daphnia magna were both >100mg/l (determined by direct observation)

The 0 to 24-hour NOEC and LOEC were 100mg/l and >100mg/l respectively (determined by direct observation).

The 0 to 48-hour NOEC and LOEC were 100mg/l and >100mg/l respectively (determined by direct observation).

In this case, isononanoic acid was the substance name given to the product ColaTrope INC prior to the ECHA inquiry. It is the 'same' substance as sodium 3,5,5-trimethylhexanoate. The test was carried out on the product.

A supporting study for the K salt gave the following information and was in agreement with the results of the Na salt study as expected.

A static Daphnia magna acute immobilisation test was performed using a single concentration of 100 mg/L test item. All results are given in relation to nominal test item concentrations: NOEC >= 100 mg/l and LOEC > 100 mg/l.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L