Fatty acids C18-C22 (even numbered), tetraesters with pentaerythritol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

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

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: source, RA-A, CAS 62125-22-8, 2005, P. subcapitata 72 h, RL2

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

> 180 - < 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: source, RA-A, CAS 62125-22-8, 2005, P. subcapitata 72 h, RL2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: source, RA-A, CAS 68604-44-4, Oleon, 2010, D. subspicatus 72 h, RL2

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

Remarks on result:

other: source, RA-A, CAS 68604-44-4, Oleon, 2010, D. subspicatus 72 h, RL2

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

Remarks on result:

other: source, RA-A, CAS 68604-44-4, Oleon, 2010, D. subspicatus 72 h, RL2

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

biomass

Remarks on result:

other: source, RA-A, CAS 68604-44-4, Oleon, 2010, D. subspicatus 72 h, RL2

Description of key information

No effects up to the limit of water solubility; read-across.

Additional information

No study investigating the toxicity of fatty acids C18-C22 (even numbered), tetraesters with pentaerythritol to aquatic algae is available. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across to the structurally related source substances 2,2-bis[[(1-oxoisooctadecyl)oxy]methyl]-1,3-propanediyl bis(isooctadecanoate) (CAS 62125-22-8) and fatty acids, C16-18 and C18-unsatd., tetraesters with pentaerythritol (CAS 68604-44-4) is applied.

Based on the high degree of similarity between the structural and physico-chemical properties of the target and source substances, the source substances are considered as suitable representative for the evaluation of the short-term toxicity of the target substance to aquatic invertebrates. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

A study investigating the toxicity to aquatic algae and cyanobacteria of 2,2-bis[[(1-oxoisooctadecyl)oxy]methyl]-1,3-propanediyl bis(isooctadecanoate) (CAS 62125-22-8) is available. The study was performed according to OECD 201. The green algae Pseudokirchneriella subcapitata was exposed under static conditions to nominal concentration of 100, 180, 320, 560 and 1000 mg/L. The test solution was prepared as water accommodated fraction (WAF) by adding the appropriate amount of test substance with subsequent stirring followed by settling. After the test duration of 72 h an EL50 > 1000 mg/L (nominal) based on growth rate was determined, the EL10 ranged from > 180 - < 320 mg/L. It can hence be concluded that the test substance will not exhibit effects to aquatic algae up to the limit of water solubility.

The second study investigated the toxicity of fatty acids, C16-18 and C18-unsatd., tetraesters with pentaerythritol (CAS 68604-44-4) to aquatic algae and cyanobacteria. The limit study was performed according to OECD 201. A water accommodated fraction (WAF) was prepared. The green algae Desmodesmus subspicatus was exposed to a nominal concentration of 100 mg/L. The test solution was prepared by adding the appropriate amount of test substance with subsequent stirring followed by filtration. No effect on growth rate and biomass of Desmodesmus subspicatus up to the limit of water solubility was observed resulting in an EL50 > 100 mg/L (nominal) and a NOELR of ≥ 100 mg/L (nominal), respectively for growth rate and biomass.

In addition, aquatic toxicity of the substance is unlikely to occur due to the low bioavailability of the substance in water. Due to the high potential for adsorption, the substance can be effectively removed in conventional sewage treatment plants (STPs) by sorption to biomass. The low water solubility (< 0.518 mg/L at 20 °C, OECD 105) and high estimated log Kow (> 10, QSAR, VEGA 1.1.3) indicate that the substance is highly lipophilic. If released into the aquatic environment, the substance undergoes extensive sorption on organic matter. Thus, the bioavailability in the water column is reduced rapidly. Furthermore, as the substance has a high molecular weight of 1370.31 – 1426.42 g/mol, it is unlikely that it is readily absorbed, due to the steric hindrance of crossing biological membranes.

Based on the available results from structurally related source substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which are characterized by a similar ecotoxicological profile and comparable structure, a low bioavailability of the substance in water and a steric hindrance of crossing biological membranes, it can be concluded that fatty acids C18-C22 (even numbered), tetraesters with pentaerythritol will not exhibit effects to aquatic algae up to the limit of water solubility.

References

Hsieh, A. and Perkins, E. G. (1976). Nutrition and Metabolic Studies of Methyl Ester of Dimer Fatty Acids in the Rat. Lipids, 11(10):763-768.

Lipinski et al. (2001). Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv. Drug Del. Rev. 46: 3-26.