Glycerol trioctanoate

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:

02 Mar - 05 Mar 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP-Guideline study with acceptable restrictions: The nominal concentrations were calculated from the concentration (TOC analysis) of the stock solution and related to the test substance. It can not be ruled out that the test substance concentration is influenced by the diester component (1.2%) included in the triester.

Qualifier:

according to guideline

Guideline:

other: Guideline 88/302/EWG (Algal Inhibition Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of the poorly soluble test substance was prepared by adding 1 g/L of the test substance into destilled water and subsequently stirring for 18 h. Afterwards the solution was filtrated and the TOC content was determined. The DOC content of the stock solution is 1.3 mg/L which equals to 2.0 mg/L of the test substance.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: CHODAT 86.81 SAG
- Source: Institut für Wasser-, Boden- und Lufthygiene Berlin - afterwards own cultivation
- Method of cultivation: three days before test initiation, a preculture was reared from a stock culture with a cell density of about 20000 cells/mL

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 ± 2 °C

pH:

Test start: 8.1 - 8.3
End of test: 9.0 - 9.2

Nominal and measured concentrations:

Nominal concentrations: 0.2, 0.34, 0.6, 1.0, 1.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Aeration: yes, sterile aeration
- Initial cells density: 2x10E4 cells/mL
- Control end cells density: 76x10E4 cells/mL
- No. of vessels per concentration: 3
- No. of vessels per control: 3

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: destilled water
- Intervals of water quality measurement: pH at the beginning and at the end

OTHER TEST CONDITIONS
- Photoperiod: continuously
- Light intensity and quality: 8000 Lux

EFFECT PARAMETERS MEASURED: Algal growth was recorded after 0, 24, 48 and 72 hours test duration.
- Determination of cell concentrations: Photometrically: The absorption was measured at 685 nm. The values were converted into cells/mL with the help of a calibration curve.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

other: filtered test substance

Basis for effect:

growth rate

Remarks on result:

other: No effect up to the limit of the water solubility was observed.

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

other: filtered test substance

Basis for effect:

growth rate

Remarks on result:

other: No effect up to the limit of the water solubility was observed. This value is given as NOEC in the study report.

Details on results:

- Exponential growth in the control: yes
- Effect concentrations exceeding solubility of substance in test medium: no

Reported statistics and error estimates:

The EC values could not be calculated with a probit analysis as no effect was observed.

Under conditions tested no effect up to the limit of the water solubility of the test substance was observed.

Table 1: Mean values of cell numbers in dependency of test duration and test substance concentration.

Cell numbers (10E4 cells/mL)
Concentration (mg/L)	Test duration (h)
	0 h*	24 h	48 h	72 h
Control	2	5	24	76
0.20	2	6	23	77
0.34	2	6	24	76
0.60	2	5	22	76
1.0	2	6	25	85
1.8	2	6	23	84

* no mean value

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Nov-17 Nov 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study with acceptable restrictions (precipitation occurred in those test vessels where the substance was directly added, probably creating the observed effects by physical interference)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

. Additionally consideration of the "VCI-Konzept-Entwurfes für die (akute) aquatische Prüfung von schwerlöslichen Stoffen vom 31.1. 1994"

Deviations:

yes

Remarks:

only 300 lux light intensity

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Both test runs (a) separated from undissolved test substance and b) directly weighed in)
- Sampling method: samples were taken at 0, 24, 48, 72 hours

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Due to the low solubility of the test substance two different test solutions were prepared according to the VCI-concept for poorly soluble substances:
a) Test solution with 100 mg/L and subsequently separation of undissolved test substance: 100 mg test substance were added to 1 L test medium and stirred for 24h. Afterwards the undissolved test substance was separated by filtration with a fibre glass filter (pretreated with 1 molar NaOH). For each replicate 100 mL aliquot of the filtrate were used, with algae inoculated and incubated.
b) 100 mg/L directly weighed in solution
The test substance was directly weighed in and shaked for 24h in a Clim-O-Shake.
To each replicate 10 mL of a 10times-concentrate of the mineral medium (according to DIN 38412/9) was added and subsequently filled up to 100 mL with deionised water. Afterwards the algae suspension was added and the incubation started.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): Pflanzenphysiol. Inst. of University Göttingen


ACCLIMATION
- Acclimation period: 3 to 4 days of preincubation in test medium without test substance

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

23 °C

pH:

Control: 8.0 (0h); 9.8 - 10.4 (72h)
Test solution a) 8.0 (0h); 10.4 (72h)
Test solution b) 8.0 (0h); 8.6 (72h)
The increase of the pH during the incubation time was not caused by the substance but results from the strong cell growth of the algal cells. A significant influence onto the test result is unlikely.

Nominal and measured concentrations:

Nominal concentration: 100 mg/L
Measured concentrations:
Test solution a) separation of undissolved matter: 0h - < 0.05 mg/L; 24h - < 0.05 mg/L; 48 h - < 0.05 mg/L; 72h < 0.05 mg/L. The recovery was lower than the LOQ which means that the separation was quantitative.
Test solution b) directly weighed in without separation: 0h - 78.9 mg/L; 24h - 18.9 mg/L; 48 h - 6.0 mg/L; 72h - 5.0 mg/L. Due to the inhomogeneity of the test suspension, the recovery was at test begin 80% and decreased to 5% from 0h to 72h.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 300 mL Erlenmeyer flasks, filled with 100 mL
- Initial cells density: 1x10E4 cells/mL
- Control end cells density: 8.6x10E5 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3


GROWTH MEDIUM
- Standard medium used: yes, according to DIN 38412/9


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water
- Culture medium different from test medium: preadaption to test medium for 3-4 days)
- Intervals of water quality measurement: after 72h


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: not mentioned
- Photoperiod: continuous
- Light intensity and quality: 300 Lux (daylight spectrum)


EFFECT PARAMETERS MEASURED: growth rate after 24, 48 and 72h
- Determination of cell concentrations: Coulter counter


TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 µg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: test solution a) with separation of undissolved test substance; no effect up to the limit of the water solubility of test substance was observed.

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: test solution b) without separation of undissolved test substance

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Any observations that might cause a difference between measured and nominal values: yes, in test solution b) where the undissolved matter was not filtered out
- Other observations: After an incubation time of 24h bacteria growth was observed in 2 of 3 replicates and after 48h/72h in all replicates of solution a). For solution b) bacteria growth was observed after 24h/48h/72h as well as a cloudiness.
- Effect concentrations exceeding solubility of substance in test medium: In test solution b) an effect was observed which can be attributed to the undissolved matter (see Remarks on results including tables and figures)

The test with test solution a), a test solution where the undissolved test substance was filtered out, showed no effects on the growth rate of Scenedesmus subspicatus. Therewith, it can be stated that no effect up to the limit of the water solubility of the test substance occurred under conditions tested.

Thus, the massive inhibition of algae growth observed in test solution b) where the undissolved test substance was not filtered out, can be attributed to physical impacts of the undissolved test substance and not to a systemic toxicity of the test substance.

Table 1: Cell concentrations and pH-values

Nominal test substance concentration [mg/L]	Alga cell concentrations [1/mL]			pH values
	Incubation time [h]			Incubation time [h]
	24	48	72	0	72
Control	4.3E+04	2.4E+05	8.6E+05	8.0	9.8-10.4
100 a)	4.0E+04	1.75E+05	1.1E+06	8.0	10.4
100 b)	2.7E+04	6.7E+04	7.3E+04	8.0	8.6

 

 

Table 2: Growth rates and inhibition of growth rates

Concentration [mg/L]	Growth rates after …h incubation
	24 [cells/(mL*h)]	48 [cells/(mL*h)]	72 [cells/(mL*h)]
0	0.0611	0.0659	0.0618
100 a)	0.0578	0.0594	0.0650
100 b)	0.0409	0.0395	0.0277
	Inhibition of growth rates after … h incubation
	24 [%]	48 [%]	72 [%]
100 a)	5.5	9.8	-5.1
100 b)	33.1	40.0	55.2

 

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Jul-23 Jul 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- For analytical measurements a solution was prepared in the same way as test solutions were prepared but without algae
- Samples were taken from all concentrations at 0 and 72 hours

Vehicle:

no

Details on test solutions:

- The poorly water soluble test substance was added to distilled water in a concentration of 1 g/L and stirred for 18 hours. Afterwards the solution was filtrated and the TC-content determined. The TC-content was < 1 mg/L. This solution was used as stock solution and further diluted (differential loading) for the test concentrations

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: CHODAT (86.81 SAG)
- Source (laboratory, culture collection): Institut für Wasser-, Boden- und Lufthygiene, Berlin; afterwards own cultivation
- Method of cultivation: three days prior to test initiation a preculture was cultivated from the stock culture. From this preculture the test cultures were inoculated with a cell density of approx. 20000 cells/mL

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 ± 2 °C

pH:

Start of test: 8.1 - 8.3
End of test: 8.6 - 8.7

Nominal and measured concentrations:

- The test solutions were diluted from a stock solution with a concentration of < 1 mg/L. Dilutions and measured concentrations are listed in Table 1

Details on test conditions:

TEST SYSTEM
- Initial cells density: 2 x 10E4 cells/mL
- Control end cells density: 91 x 10E4 cells/mL
- No. of vessels per concentration (replicates): 5-8 replicates
- No. of vessels per control (replicates): 5-8 replicates


GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: distilled water


OTHER TEST CONDITIONS
- Light intensity and quality: 8000 Lux, white


EFFECT PARAMETERS MEASURED: Number of cells after 24, 48 and 72 hours
- Determination of cell concentrations: The number of cells were determined photometrically. The absorption at 685 nm was measured and afterwards the absorption values were converted into the parameter "cells/mL"


TEST CONCENTRATIONS
- Spacing factor for test concentrations: < 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.449 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: TC content

Basis for effect:

growth rate

Remarks on result:

other: No effect up to the limit of the water solubility of the test substance was observed.

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 0.449 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: TC content

Basis for effect:

growth rate

Remarks on result:

other: No effect up to the limit of the water solubility of the test substance was observed.

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.449 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: TC content

Basis for effect:

growth rate

Remarks on result:

other: No effect up to the limit of the water solubility of the test substance was observed.

Details on results:

- Exponential growth in the control: yes

No effect was observed up to the limit of the water solubility of the test substance which was reached under test conditions. The ErC50, ErC10 and ErC90 (0 -72h) are > water solubility under conditions tested.

Table 2: Mean values of cell numbers in dependency of test duration and test substance concentration. The concentrations are based on dilutions (mL/L)

Dilution (mL/L)	Cell numbers (*10E+04/mL) during test period
	0h	24h	48h	72h
Control	2	4	24	91
100	2	5	25	92
170	2	5	26	95
300	2	5	28	99
500	2	6	29	101
900	2	7	29	102

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Oct - 12 Oct 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

other: OECD Guidance Document No. 23 on Aquatic Toxicity of Difficult Substances and Mixtures, OECD 2000

GLP compliance:

yes (incl. QA statement)

Remarks:

LUBW Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg, Karlsruhe, Germany

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Analysis was performed in additional test vessels without algae to avoid an influence of the algae on the measured concentrations. At the start and at the end of the experimental phase samples (4 mL) were taken and filtered with a 0.45 µm cellulose acetate (CA) membrane filter (Whatman FP 30/0.45 µm). First the filter was washed with 100 mL bi-distilled water and with 15 mL sample. Additional samples were measured at the end of the study (72h) from the original test vessels with algae to get an impression of the influence of the organisms on the exposure concentration. Algae were separated by filtration before analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Due to the low water solubility of the test item, the study was performed with WAFs ("water accommodated fraction") prepared with algal growth medium according to OECD 201. The test item was weighted on a piece of polyethylene foil (rinsed with ethanol and H2O bidest. before) which was transferred together with the test item into a defined volume of Algal medium into a 2000 mL beaker. The suspension was stirred for 48 hours at 21 - 22 °C in the dark. For stirring a magnetic stirrer with a 2 cm stir bar was used. After stirring was stopped, the suspension was allowed to float and sediment for a period of 65 minutes. After stopping the stirring in all WAFs white flakes were observed which sedimented. After one hour sedimentation and flotation period no particles could be observed in suspension which could affect the organisms physically. Therefore the WAFs were not filtered to obtain the water soluble fractions (WSF). The test solutions were taken from the middle of the suspension in the beakers using a glass tube and transferred into the test vessels.
The loading rates (LR) for the WAFs were chosen 1.11-fold higher than the nominal loading rates intended in the test solution so as to take into account the dilution by the algal inoculum suspension (10%).
45 mL test solution was transferred into each test vessel (100 mL wide necked Erlenmeyer flask) and 5 mL of the algae inoculum suspension (0.8 x 10E+05 algae/mL) were added to obtain an algae starting concentration of 0.8 x 10E+04 algae/mL. For the controls, 5 mL algae inoculum suspension was added to 45 mL algal medium. This medium was stirred in the same way as the WAF.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Green alga
- Strain: SAG No. 86.81
- Source (laboratory, culture collection): German Environmental Agency (UBA), Berlin-Marienfelde, cultured in the laboratory of Hydrotox GmbH since June 2012.
- Method of cultivation: Twice a week the stock suspension is diluted 2:50 into fresh Holm-Hansen medium under axenic conditions to keep it in exponential growth.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.9 - 23.2 °C

pH:

6.92 - 7.76

Nominal and measured concentrations:

Nominal: control, 4.3, 9.4, 20.7, 45.5, and 100 mg/L (WAF, nominal)
Measured concentrations ranged from 4.50 to 4.86 mg/L at a nominal loading rate of 100 mg/L and from < LOD to 1.19 mg/L for a nominal loading rate of 20.7 mg/L. Concentrations at the lowest nominal loading rate of 4.3 mg/L could not be detected (< LOD).

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Type: closed (sealed with a sterile cellulose stopper)
- Material, size, headspace, fill volume: 100 mL wide necked glass Erlenmeyer flask
- Initial cells density: 0.8 x 10E04 cells/mL
- Control end cells density: 7.8 x 10E05 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, according to OECD guideline 201


OTHER TEST CONDITIONS
- Photoperiod: continuous
- Light intensity and quality: The flasks are illuminated laterally by eight fluorescent tubes (58 Watt each) which are separated from the incubation chamber by heat absorbing glass. Light intensity is continuously variable and was set on 45% of the maximum light intensity resulting in a mean light intensity of 120 µE/m2 s ± 5.7% (PAR)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Chlorophyll measurement: The algal growth was determined by measuring the chlorophyll fluorescence as a measure for algal biomass. At the start of the test and after 24, 48 and 72 hours, 200 µL samples were taken out of each test vessel and chlorophyll fluorescence was measured in a 96-well micro-plate for each sample using a fluorescence micro-plate reader (excitation wave length: 465 nm, emission wave length: 670 nm). The conversion factor between the chlorophyll fluorescence and the algal count, as required in the OECD guideline, was determined by correlating both parameters. Several different algal cell concentrations were measured using the same algal pre-culture as in the test. The algal count was determined for a cell size between 3 and 9 µm using a Coulter Counter 72.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

20.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.19 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Measured final concentration

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

9.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

49 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 31.3 - 78.8

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

29.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Remarks on result:

other: 95% CL: 28.6 - 30.6

Duration:

72 h

Dose descriptor:

LOELR

Effect conc.:

45.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOELR

Effect conc.:

20.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Details on results:

- Growth inhibition occurred at nominal loading rates of 45.5 mg/L and 100 mg/L (53.8% and 77%, respectively). No significant effects were observed at any other treatment group.

Results with reference substance (positive control):

EC50 (growth rate) = 0.94 mg/L
EC50 (yield) = 0.49 mg/L

Table: Mean growth rates and mean yields and its inhibitions compared to the control

	A	B	C	D	E	Control
Loading Rate mg/L	100	45.5	20.7	9.4	4.3	-
Number of replicates	3*	3	3	3	3	6
Mean growth rate	0.370	0.743	1.555	1.583	1.588	1.610
Mean yield**	32	341	4584	5259	5242	5138
Mean inhibition of growth rate	77.0%	53.8%	3.4%	1.7%	1.4%	-
Mean inhibition of	99.4%	93.4%	10.8%	-2.4%**	-2.0%**	-

* for replicate C the mean value of replicate A and B was taken as substitute for the 0h fluorescence value

** negative inhibition means growth propagation

Reference 5

Endpoint:

toxicity to aquatic algae and cyanobacteria

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

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

other: filtered test substance

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 620-67-7, Sasol, 1993, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

20.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.19 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

9.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

49 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

29.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

LOELR

Effect conc.:

45.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

LOELR

Effect conc.:

20.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

other: yield

Remarks on result:

other: Source: CAS 85536-07-8, Cremer, 2013, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 µg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: test solution with separation of undissolved test item; Source: CAS 65381-09-1, BASF, 1996, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: test solution without separation of undissolved test item; Source: CAS 65381-09-1, BASF, 1996, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.449 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: TC content

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 73398-61-5, Sasol, 1994, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 0.449 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: TC content

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 73398-61-5, Sasol, 1994, Desmodesmus subspicatus

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.449 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: TC content

Basis for effect:

growth rate

Remarks on result:

other: Source: CAS 73398-61-5, Sasol, 1994, Desmodesmus subspicatus

Additional information

Since no studies investigating the toxicity of Glycerol trioctanoate (CAS 538-23-8) to aquatic algae are available, in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5, a read-across to the structurally related source substances Glycerol triheptanoate (CAS 620-67-7), Glycerides, C8-10 mono and di (CAS 85536-07-8), Decanoic acid, ester with 1,2,3-propanetriol octanoate (CAS 65381-09-1), and Triglycerides, mixed decanoyl and octanoyl (CAS 73398-61-5) was conducted. The source substances are representative to evaluate the toxicity of the target substance to aquatic algae. This read-across is justified in detail within the analogue justification in IUCLID section 13.

The target substance Glycerol trioctanoate (CAS 538-23-8) is a monoconstituent characterized by the alcohol component glycerol which is fully esterified with octanoic acid to give glycerol triesters of octanoic acid.

The source substance Glycerol triheptanoate (CAS 620-67-7) is a monoconstituent characterized by the alcohol component glycerol which is esterified to give triesters of C7 fatty acids.

The source substance Glycerides, C8-10 mono and di (CAS 85536-07-8) is a UVCB substance characterized by the alcohol component glycerol and C8-10 (even numbered) fatty acids. Esterification of glycerol gives mainly mono- and diesters of C8-10 (even numbered) fatty acids.

The source substance Decanoic acid, ester with 1,2,3-propanetriol octanoate (CAS 65381-09-1) is a UVCB substance characterized by the alcohol component glycerol. Complete esterification with octanoic and decanoic fatty acids gives glycerol triesters of octanoic decanoic acid.

The source substance Triglycerides, mixed decanoyl and octanoyl (CAS 73398-61-5) is a UVCB substance characterized by the alcohol component glycerol and C6-12 (even numbered fatty acids). Esterification of glycerol gives largely triesters of C8 and C10 fatty acids. Mono- and diesters as well as C6 and C10 fatty acids occur as minor fractions.

The study with read-across substance Glycerol triheptanoate (CAS 620-67-7) was performed in a static design and under GLP according to Guideline 88/302/EWG (Algal Inhibition Test). The freshwater alga Desmodesmus subspicatus was used as test organism. The algae were exposed to nominal concentrations of 0.2, 0.34, 0.6, 1.0, and 1.8 mg/L over a period of 72 hours. No effect on growth rate was observed up to the limit of water solubility. The ErC 50 (72 h, nominal) was determined as > 1.8 mg/L. The ErC 10 (72 h, nominal) was determined as > 1.8 mg/L.

The study with read-across substance Glycerides, C8-10 mono and di (CAS 85536-07-8) was performed in a static design under GLP according to OECD guideline 201 (Alga, Growth Inhibition Test). The freshwater alga Desmodesmus subspicatus was used as test organism. The algae were exposed to nominal concentrations of 4.3, 9.4, 20.7, 45.5, and 100 mg/L (WAF) over a period of 72 hours. Analytical measurements revealed concentrations of 4.50 to 4.86 mg/L at a nominal loading rate of 100 mg/L and < LOD to 1.19 mg/L at a nominal loading rate of 20.7 mg/L. Concentrations at the lowest nominal loading rate of 4.3 mg/L could not be detected (< LOD). Growth inhibition occurred at nominal loading rates of 45.5 mg/L and 100 mg/L (53.8% and 77%, respectively). No significant effects were observed at any other treatment group. The EL50 (72 h, growth rate) was determined as 49 mg/L. The EC50 (72 h, yield) was determined as 29.5 mg/L.

The study with read-across substance Decanoic acid, ester with 1,2,3-propanetriol octanoate (CAS 65381-09-1) was performed as a limit test in a static design and under GLP according to EU Method C.3 (Algal Inhibition Test). The freshwater alga Desmodesmus subspicatus was used as test organism. The algae were exposed to a single nominal concentration of 100 mg/L over a period of 72 hours. The concentration of the test solution (a) after quantitative separation of undissolved matter was < 0.05 mg/L. The concentration of the test solution (b) without separation of undissolved matter was 78.9 mg/L at test start and decreased to 5 mg/L at 72 h. No effect on growth rate was observed up to the limit of water solubility for test solution (a). The ErC 50 (72 h, measured) was determined as > 10 µg/L for test solution (a). In test solution (b) an effect was observed which can be attributed to physical impacts of the undissolved test substance and not to a systemic toxicity of the test substance. The ErC 50 (72 h, measured) was determined as < 100 mg/L for test solution (b).

The study with read-across substance Triglycerides, mixed decanoyl and octanoyl (CAS 73398-61-5) was performed in a static design and under GLP according to EU Method C.3 (Algal Inhibition Test). The freshwater alga Desmodesmus subspicatus was used as test organism. The algae were exposed to measured initial concentrations (TC content) of 0.096, 0.113, 0.128, 0.357, and 0.529 mg/L over a period of 72 hours. No effect on growth rate was observed up to the limit of water solubility. The ErC 50 (72 h) was determined as > 0.449 mg/L. The NOEC (72 h) was determined as≥0.449 mg/L.

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 Glycerol trioctanoate (CAS 538-23-8) shows no toxicity to aquatic algae up to the limit of water solubility (< 0.532 µg/L at 20°C).