2-ethyl-2-[[(1-oxononyl)oxy]methyl]propane-1,3-diyl dinonan-1-oate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Microlitre volumes of a stock solution of Priolube 3934 in anhydrous diethyl ether were pipetted into separating flasks containing 10ml ISO medium. The diethyl ether was allowed to evaporate off, so as to provide calibration standards covering the concentration range of the samples. To each of these calibration standards, and any 10 ml volumes of samples provided, 5ml chloroform was added and the flasks were shaken for two minutes. The lower chloroform layer was run off into a glass bottle and evaporated to dryness at about 65°C under a flow of nitrogen. The calibration standards and test samples were redissolved in 100ul of choroform and spiked with 10ul of an internal standard solution (680 mg/I stearic acid methyl ester in chloroform).

Vehicle:

no

Details on test solutions:

0.020 g of Priolube 3934 was dispersed in 1000 ml of distilled water using a high shear mixer at 16 000 rpm for 20 minutes to prepare a 20 mg/I stock. A range of test substance concentrations (nominally 0.10, 0.32, 1.0, 3.2 and 10 mg/I) was prepared by diluting the stock with ISO medium.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Scenedesmus subspicatus is widely distributed in freshwaters and is easily maintained in laboratory culture in synthetic media. It is one of two species used in the ISO algal growth inhibition test and is recommended for use in algal growth inhibition tests in OECD guideline 201.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Not reported

Test temperature:

21 - 23 °C

pH:

At T0 = 7.2-7.6
At the end of the test = 7.7- 9.5

Dissolved oxygen:

Not reported

Salinity:

Not reported

Conductivity:

Not reported

Nominal and measured concentrations:

See table below (Table 1)

Details on test conditions:

TEST SYSTEM
- Test vessel: loosely stoppered and placed in an orbital illuminated incubator
- Initial cells density: 10E+04 cells/mL
- No. of vessels per concentration: 4
- No. of vessels per control: 7

GROWTH MEDIUM
- Standard medium used: yes (ISO Algal medium)

OTHER TEST CONDITIONS
- Photoperiod: continuous light

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: samples were taken at 0, 48 and 72 h and the cell densities were determined by using a Coulter Counter (at 440 nm)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 4.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 4.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The test substance did not interfere with the Coulter Counter to an unacceptable extent and consequently it was decided that the counts made on the Coulter Counter gave the best assessment of algal concentrations.
The calculated percentage inhibition of growth rate and biomass at each mean measured concentration of Priolube 3934 at 72 hours are given in Table 2 below.
There was a 52 fold mean increase in the cell density of control cultures over 72 hours. The control growth was therefore qualitatively acceptable.

Table 2: Percentage Inhibition of Test Algal Cultures

48 hours			72 hours
Mean concentration (mg/I)	Biomass	Growth rate	Mean concentration (mg/I)	Biomass	Growth rate
0.17	28	15	0.14	26	9.0
0.21	23	10	0.16	10	1.6
0.42	30	15	0.32	5.4	0.94
1.3	51	25	1.0	-0.54	-4.6
5.4	87	66	4.4	23	6.3

Validity criteria fulfilled:

yes

Conclusions:

72 hour EC50 (72h) >4.4 mg/L (growth inhibition & biomass) It was not possible to determine the 72 hour NOEC because there was no statistically significant adverse effect at the highest concentration tested

Executive summary:

The toxicity of Priolube 3934 to the freshwater green alga Scenedesmus subspicatus was determined in compliance with ISO, EEC and OECD standard methods.

A range of concentrations of the test substance (nominally 0.10, 0.32, 1.0, 3.2 and 10 mg/I) was prepared in ISO medium.

The concentration of Priolube 3934 in each of the test concentrations was analysed at o, 24, 48 and 72 hours. Analysis of the 0 hours samples indicated that the mean of 0 hours measured concentrations was 101 % (spread 81 - 150 %) of nominal concentrations.

Due to limits of detection, corrected measured concentrations below 0.3 mg/l should be treated with caution.

EC50 72h > 4.4 mg/l

It was not possible to determine the 72 hour NOEC from these data because there was no statistically significant effect at the highest concentration tested.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

other: Read across with analogous substance

Adequacy of study:

supporting study

Study period:

1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Microlitre volumes of a stock solution of Priolube 3988 in anhydrous diethyl ether were pipetted into 250 ml separating flasks containing 150 ml ISO medium. The diethyl ether was allowed to evaporate for 5 minutes so as to provide calibration standards covering the concentration range of the samples. To each of these calibration standards and any 150 ml volumes of samples provided, 15 ml chloroform was added and the flasks were shaken for 2 minutes. The lower chloroform layer was run off into a glass bottle and evaporated to dryness at about 65 °C under a flow of nitrogen. The calibration standards and test samples were redissolved in 100 mI of chloroform and spiked with 10 mI of an internal standard solution (736 mg/l stearic acid methyl ester in chloroform). The spiked extracts were then analysed by gas chromatography with a flame ionisation detector.

Vehicle:

no

Details on test solutions:

0.020 g of priolube 3988 was dispersed in 1000 ml of distilled water using a high shear mixer at 16 000 rpm for 20 minutes to prepare a 20 mgl/l stock.
A range of concentrations of the test substance (nominally 0, 0.10, 0.32, 1.0, 3.2 and 10 mg/l) was prepared by diluting the stock with ISO medium.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Scenedesmus subspicatus is widely distributed in freshwaters and is easily maintained in laboratory culture in synthetic media. It is one of two species used in the ISO algal growth inhibition test and is recommended for use in algal growth inhibition tests in OECD guideline 201.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Not reported

Test temperature:

21 - 23.5 °C

pH:

At T0 = 6.8-7.3
At the end of the test = 7.6- 7.8

Dissolved oxygen:

Not reported

Salinity:

Not reported

Conductivity:

Not reported

Nominal and measured concentrations:

See table below (Table 1)
Nominal: 0.0, 0.1, 0.32, 1.0, 3.2 and 10 mg/L
Measured: < 0.04, 0.18, 0.23, 0.30, 1.7 and 3.7 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: loosely stoppered and placed in an orbital illuminated incubator
- Initial cells density: 10E+04 cells/mL
- No. of vessels per concentration: 4
- No. of vessels per control: 7

GROWTH MEDIUM
- Standard medium used: yes (ISO Algal medium)

OTHER TEST CONDITIONS
- Photoperiod: continuous light

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: samples were taken at 0, 48 and 72 h and the cell densities were determined by using a Coulter Counter (at 440 nm)

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 3.7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 3.7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

lt was not possible to determine the 48 and 72 hour EC50s or the 72 hour NOEC as there was no inhibitory effect at the highest concentration tested. There was an indication that the test substance caused an increase in celi growth at concentrations of 0.3 mg/I and above.

Geometric mean conc. (mg/l)	Biomass		Growth rate
	48 hours	72 hours	48 hours	72 hours
0.18	-55	10	-40	-1.5
0.23	17	-14	1.5	-3.7
0.30	-110	-0.31	-62	-3.5
1.7	-200	-6.5	-79	-4.7
3.7	-2200	-58	-240	-15

Validity criteria fulfilled:

yes

Conclusions:

It was not possible to determine the 48 and 72 hour EC50s or the 72 hour NOEC as there was no inhibitory effect at the highest concentration tested. There was an indication that the test substance caused an increase in cell growth at concentrations of 0.3 mg/l and above.

Executive summary:

The toxicity of Priolube 3988 to the freshwater green alga Scenedesmus subspicatus was determined in compliance with ISO, EEC and OECD standard methods.

A range of concentrations of the test substance (nominally 0.10 - 10 mg/l) was prepared in ISO medium.

The concentration of Priolube 3988 in each of the test concentrations was analysed at 0 and 72 hours.

Description of key information

Two studies have been conducted (one on the target substance TMP Pelargonate and one on the analogue TMP Triisostearate)

indicating no effect at the maximum tested concentration, equivalent to nominal 10 mg/l. The measured concentrations are much lower due to the water solubility and hydrolytic instability of the substances.

The target substance is of extremely low water solubility (0.078 µg/L) and therefore the test was performed in supersaturated solution. No lethality / immobility / growth rate reduction could be observed up to the highest attainable test item concentration. Because no hazard was identified, no key values for chemical safety assessment are given below.