Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic and n-heptanoic acids

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:

13 Jun - 16 Jul 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(1984)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom, date of inspection 23 March 1998

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control - 100 mg/L
- Sampling method: Water samples were taken (replicates R1-R3 and R4-R6 pooled) at 0 and 72 h for quantitative analysis.
- Sample storage conditions before analysis: Duplicate samples were taken at 0 h and stored frozen (approx. -20 °C) for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: An amount of test material (2000 mg) was added to the culture medium and stirred for 23 h to give the 100 mg/L loading rate. The stirring was stopped after 23 h and the mixture allowed to stand for 1 h. The water accommodated fraction (WAF) was then removed by filtration through 0.45 µm filters to give the 100 mg/L loading rate WAF. An aliquot (2 L) of the 100 mg/L loading rate WAF was mixed with algal suspension (20 mL).
- Controls: The control group was maintained under identical conditions but not exposed to the test material.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: CCAP 276/20
- Source: Culture Centre for Algae and Protozoa (CCAP), Institute of Freshwater Ecology, Ferry House, Ambleside, Cumbria
- Method of cultivation: Cultures were maintained in the laboratory by a periodic replenishment of culture medium at a temperature of 21 ± 1 °C under continuous illumination (approx. 7000 lux) and constant aeration.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

24 ± 1 °C

pH:

Control: 7.5 (0 h), 8.9-9.0 (72 h)
100 mg/L: 7.4 (0 h), 9.4-9.7 (72 h)

Nominal and measured concentrations:

Nominal: 100 mg/L
Measured: < 0.18 mg/L (limit of quantification)

Details on test conditions:

TEST SYSTEM
- Test vessel: conical flasks
- Type: covered with aluminium foil
- Material: glass, Size: 250 mL, Fill volume: 100 mL
- Aeration: constantly shaken at 100 rpm for 72 h
- Initial cells density: 10^4 cells/mL
- Control end cells density: 9.18x10^5 cells/mL
- No. of vessels per concentration: 6
- No. of vessels per control: 3

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

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reverse osmosis purified deionised water (Elga Optima 15+), pH adjusted to 7.5 ± 0.1

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity and quality: approx. 7000 lux

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: Samples were taken at 0, 24, 48 and 72 h and the cell densities determined by using a haemocytometer and light microscope.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 100 mg/L
- Results used to determine the conditions for the definitive study: The results showed no effect on growth at the 100 mg/L loading rate WAF.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAF)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAF)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAF)

Basis for effect:

biomass

Details on results:

- Exponential growth in the control: yes
- Any stimulation of growth found in any treatment: yes, 4% stimulation of growth after 72 h (100 mg/L)
- Effect concentrations exceeding solubility of substance in test medium: The effect concentrations exceeded the water solubility of the test substance.

Reported statistics and error estimates:

A Students t-test was performed for statistical analysis.

The test exhibited an EL50 of > 100 mg/L (nominal) based on the growth rate. No effects were observed in the range of the water solubility of the test substance. Chemical analysis of the 100 mg/L loading rate WSFs at 0 and 72 h showed the measured test concentrations to be less than the limit of quantification of the analytical method (0.18 mg/L). Exceeding the duration of stirring did not result in significant increase in TOC in test solutions.

Table 1: Cell densities in the definitive study

Nominal loading rate [mg/L]	Cell densities [cells/mL]
	0 h	24 h	48 h	72 h
Control R1	6.65x10³	3.61 x10^5	6.94 x10^5	8.33 x10^5
Control R2	5.00 x10³	3.89 x10^5	5.83 x10^5	9.18 x10^5
Control R3	5.00 x10³	3.89 x10^5	5.56 x10^5	8.33 x10^5
Control Mean	5.55 x10³	3.80 x10^5	6.11 x10^5	8.61 x10^5
100 R1	3.35 x10³	4.72 x10^5	5.56 x10^5	1.17 x10^6
100 R2	5.00 x10³	3.89 x10^5	5.56 x10^5	9.18 x10^5
100 R3	5.00 x10³	3.89 x10^5	5.83 x10^5	1.00 x10^6
100 R4	6.65 x10³	4.17 x10^5	5.28 x10^5	6.68 x10^5
100 R5	5.00 x10³	4.17 x10^5	6.11 x10^5	8.33 x10^5
100 R6	3.35 x10³	4.17 x10^5	5.56 x10^5	9.18 x10^5
100 Mean	4.73 x10³	4.17 x10^5	5.56 x10^5	9.18 x10^5

Table 2: Inhibition of growth rate and biomass

Nominal loading rate [mg/L]	Area under curve at 72 h	% inhibition	growth rate (0-72 h)	% inhibition
Control	3.38x10^7	-	0.070	-
100	3.43x10^7	[2]	0.073	[4]

[increase in growth as compared to the controls]

Conclusions:

EL50 (72 h, growth rate) >100 mg/L (nominal) (Scenedesmus subspicatus, OECD 201)
NOELR (72 h, growth rate) ≥100 mg/L (nominal) (Scenedesmus subspicatus, OECD 201)
No effects up to the limit of the water solubility of the substance.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

In accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read across to the structurally similar analogue substance Dipentaerythritol with fatty acids C5 and C9 iso (CAS 647028-25-9) was conducted to fulfil the data requirements according to Annex VII of Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic and n-heptanoic acids. (CAS 1379424-11-9) in regard to toxicity to aquatic algae.
This read-across is justified in detail in the overall summary (IUCLID section 6.1) and within the analogue justification in IUCLID section 13. The source substance consists of the same alcohol component (dipentaerythritol) and similar fatty acid chain lengths as the target substance (C7, C9-iso for the target substance compared to C5, C9-iso for the source substance).

The study with the read across substance Dipentaerythritol with fatty acids C5 and C9iso investigated the toxicity to algae in a GLP guidance study. The test was performed according to OECD 201 (Mead and Mullee, 2000) with Scenedesmus subspicatus exposed to a water accommodated fraction with a limit concentration of 100 mg/L. The test substance concentration was analysed using GC-analysis and resulted in a concentration of <0.8 mg/L (limit of quantification). No inhibition was observed after 72 h. Therefore, this study resulted in an EL50 of > 100 mg/L (nominal). The NOELR was derived to be 100 mg/L (nominal).

Based on the result from the structurally related substance, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5, characterized by a similar ecotoxicological profile, it can be concluded that Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic and n-heptanoic acids will not exhibit toxic effects to aquatic algae up to the limit of water solubility.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

biomass

Conclusions:

In the toxicity to aquatic algae study with source substance Dipentaerythritol wiht fatty acids C5 and C9iso (OECD 2014, Mad an Mullee, year 2000) with Scenedesmus subspicatus exposed to a water accommodated fraction with a limit concentration of 100 mg/L, no inhibition was observed after 72 h. The test substance concentration was analysed using GC-analysis and resulted in a concentration of <0.8 mg/L (limit of quantification). Therefore, this study resulted in an EL50 of > 100 mg/L (nominal). The NOELR was derived to be 100 mg/L (nominal).

Based on the resut from the structurally related substance, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5, characterized by a similar ecotoxicological profile, it can be concluded that Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic and n-heptanoic acids will not exhibit toxic effects to acquatic algae up to the limit of water solubility.

Description of key information

EL50 (72 h, growth rate) >100 mg/L (nominal) (Scenedesmus subspicatus, OECD 201)
NOELR (72 h, growth rate) ≥100 mg/L (nominal) (Scenedesmus subspicatus, OECD 201)
No effects up to the limit of the water solubility of the source substance.

Based on the result from the structurally related substance, characterized by a similar ecotoxicological profile and

in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5, it can be concluded that Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic and n-heptanoic acids will not exhibit short-term toxic effects to fish up to the limit of water solubility.