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

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification document provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EL0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

mobility

Remarks on result:

other: RA-A, CAS 68604-44-4, BASF, 1998, D. magna 48 h, RL2

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

mobility

Remarks on result:

other: RA-A, CAS 68604-44-4, BASF, 1998, D. magna 48 h, RL2

Duration:

48 h

Dose descriptor:

EL100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

mobility

Remarks on result:

other: RA-A, CAS 68604-44-4, BASF, 1998, D. magna 48 h, RL2

Description of key information

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

Additional information

No study investigating the short-term toxicity of fatty acids C18-C22 (even numbered), tetraesters with pentaerythritol aquatic invertebrates is available. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across to the structurally related source substance 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 to be suitable representatives for the evaluation of the short-term toxicity of the target substance to fish. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

The study investigated the short-term toxicity to aquatic invertebrates of fatty acids, C16-18 and C18-unsatd., tetraesters with pentaerythritol (CAS 68604-44-4). The study was performed under static conditions according to EU Method C.2 using Daphnia magna as test organism. Testing was done with the water-accommodated fraction (WAF). The WAF was prepared by adding the appropriate amount of test substance with subsequent stirring and filtering. A nominal test concentration of 100 mg/L was tested, corresponding to < 10 mg/L (detection limit). No immobilisation was observed in the treatment and the control throughout the test period of 48 h. Hence, the 48 h-EL50 is determined to be > 100 mg/L based on the nominal test concentration.

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. The relevant route of uptake of the substance in aquatic organisms is expected to be predominantly by ingestion of particle bound substance. However, 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. Following the ‘rule of 5’ (Lipinski et al., 2001), developed to identify drug candidates with poor oral absorption based on criteria regarding partitioning (log Kow > 5) and molecular weight (> 500 g/mol), the substance is considered to be poorly absorbed after oral uptake (Hsieh & Perkins, 1976).

Based on the available results from a structurally related source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is 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 short-term effects to aquatic invertebrates 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.