Monopentaerythritol tetraesters and dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic, n-heptanoic, n-octanoic and n-decanoic acids

Toxicity to aquatic algae and cyanobacteria

Description of key information

One reliable study is available. In this study Pseudokirchneriella subcapitata were exposed to a Water Accommodated Fraction of an analogue substance (EC 613 -848 -7) at a nominal loading rate of 100 mg/L under static conditions for 72 hours. The ErL50 (72 h) value was > 100 mg/L loading rate WAF. The NOELR was 100 mg/L loading rate WAF. The analogue substance is not harmful to algae.

Additional information

One reliable study is available. In this study (Vryenhoef, 2014) performed under GLP according to OECD TG 201 and EC Method C.3, green alga Pseudokirchneriella subcapitata were exposed to the analogue substance under static conditions for 72 hours at 24 °C. Due to the low aqueous solubility and complex nature of the test item, for the purposes of the test the test item was prepared as a Water Accommodated Fraction (WAF). Following a preliminary range-finding test, Pseudokirchneriella subcapitata (6 replicates) was exposed to a WAF of the test material at a nominal loading rate of 100 mg/L. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group using a Coulter Multisizer Particle Counter. ErL50 (72 h) value was > 100 mg/L loading rate WAF. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF.

The results of this study are supported by data available for the read-across substances fatty acid polyols (Fatty acids, C5-9, esters with pentaerythritol (EC 270-290-3, CAS 68424-30-6) and Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (EC 234-392-1, CAS 11138-60-6)) and their analogues is applicable based on the similarity in structure and physico-chemical properties. The substance with the CAS No. 131459-39-7 is a structural analogue of one of the read-across substances (CAS No. 68424-30-6) and can therefore be used for read-across.

The justification for read-across is presented in Section 13 Assessment reports- Read-across justification.

Two studies, investigating the toxicity to freshwater algae of Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (EC 234 -392 -1, CAS-No. 11138-60-6), were available.

During both static Algal Growth Inhibition tests no inhibiting effects on growth rate were observed within 72 hour test period at the tested concentrations. The first study (Häner, 2007) according to OECD 201 with Desmodesmus subspicatus determined a no-observed-effect concentration for growth rate (ErL0) of ≥ 100 mg/L and an ErL50 > 100 mg/L (WAF loading rate). In the second study (Craig, 2005) similar to OECD 201 with Pseudokirchnerella subcapitata an ErL50 and ErL10 > 1000 mg/L (WAF loading rate) was estimated. In addition, another algae toxicity test (Kuttler, 1998) with Desmodesmus subspicatus showed no toxicity of the test substance after 72 h at a WAF loading rate of 10000 mg/L. All results show no toxicities of Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (CAS-No.11138-60-6) in the range of water solubility (< 0.3 mg/L). Therefore, the test substance is not harmful to algae.

In a static GLP study on 3,5,5-trimethylhexanoic acid mixed tetraesters with PE and valeric acid (CAS-No. 131459-39-7), (Mead, 1999) with Scenedesmus subspicatus according to OECD 201, no inhibition on growth rate and biomass was observed at the tested WAF loading rates (EL50 (72h) > 100 mg/L, NOELR (72h) ≥ 100 mg/L). An increase in growth rate and biomass (growth rate: 2 - 4%, biomass: 2 -20%) in comparison to the controls was determined. Chemical analysis showed measured test concentrations of 2 -18 mg/L. No toxic effects were observed within the water solubility under the conditions tested.