Dodecyl laurate

Endpoint summary

Additional information

There is no experimental data available for the aquatic toxicity of lauryl laurate (CAS 13945-76-1). Therefore, the aquatic toxicity of the target substance was assessed by means of a read-across approach, through which additional data for three structurally and chemically closely related source substances was compiled in order to fulfill the standard information requirements laid down in Annex XI, 1.5, of the REACh Regulation (EC) No 1907/2006. The selected source substances fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0), tetradecyl myristate (CAS 3234-85-3), and fatty acids, C8-16, 2-ethylhexyl esters (CAS 135800-37-2) are characterized by similar fatty acid and alcohol components as the target substance.

According to Article 13 (1) of this regulation, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” For aquatic toxicity in particular, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across). In regard to the general rules for grouping of substances and the read-across approach, the regulation specifies (Annex XI, Item 1.5) that substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Based on the high degree of structural similarity as well as similar physico-chemical properties of the target and selected source substances, the target substance is expected to have a similar ecotoxicological profile as the selected source substances. A detailed analogue approach justification is provided in IUCLID section 13 of the technical dossier.

By means of the read-across approach, GLP guideline studies are available for the short-term toxicity to three trophic levels (fish, aquatic invertebrates and algae) and the long-term toxicity to two trophic levels (aquatic invertebrates and algae). In addition, one experimental study is available for the toxicity to microorganisms. In all studies, Water Accommodated Fraction solutions (WAFs) of the respective test items were prepared due to the poor water solubility (< 1.0 mg/L) common to all the source substances as well as the target substance.

For the short-term toxicity to fish, two experimental studies are available for the source substances fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) and tetradecyl myristate (CAS 3234-85-3), respectively. Both tests were performed according to OECD guideline 203. After 96 h of exposure of the model organism D. rerio to WAFs with nominal loading rates of 100 mg/L of the respective substances, no mortality was observed and it was concluded that neither substance causes short-term toxicity to fish up to the limit of water solubility.

For the short-term toxicity to aquatic invertebrates, one experimental study according to OECD guideline 202 is available for the source substance tetradecyl myristate (CAS 3234-85-3). After 48 h of exposure of the model organism Daphnia magna to a WAF with a nominal loading rate of 100 mg/L, no immobilization was observed and it was concluded that the substance does not cause short-term toxicity to aquatic invertebrates up to the limit of water solubility.

For the toxicity to aquatic algae, two experimental studies according to OECD 201 are available for the source substances fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) and tetradecyl myristate (CAS 3234-85-3), respectively. After 72 h of exposure of the model organisms Pseudokirchneriella subcapitata and Desmodesmus subspicatus to WAFs with nominal loading rates of 100 mg/L in a limit test as well as to WAFs in a geometric series with nominal loading rates of 10 to 1000 mg/L, respectively, no effects on growth rate and yield were observed in either test. On this basis it was concluded that the substances neither cause short-term nor long-term toxicity to aquatic algae up to the limit of water solubility.

For the long-term toxicity to aquatic invertebrates, two experimental studies according to OECD 211 and 202 are available for the source substances fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) and fatty acids, C8-16, 2-ethylhexyl esters (CAS 135800-37-2), respectively. After exposure of the model organism D. magna to WAFs with nominal loading rates of 10 and 100 mg/L test item for 21 d, respectively, no effects on reproduction were recorded. Hence, it was concluded that the substances do not cause long-term toxicological effects on aquatic invertebrates up to the limit of water solubility.

For the toxicity to activated sludge microorganisms, one experimental study according to OECD 209 is available for source substancefatty acids, C8-10, C12-18-alky esters (CAS 95912-86-0), in which 62.5 – 1000 mg/L test item was inoculated with activated sludge inoculum for 3 h. No effects on the respiration rate were observed.Thus, it was concluded that the substance does not have inhibitory effects on the activity of activated sludge microorganisms and an inhibition of degradation in sewage treatment plants is therefore not expected.

In summary, the compiled data for the short-term toxicity to fish, aquatic invertebrates and algae as well as for the long-term toxicity to aquatic invertebrates and algae neither indicate any short-term nor long-term toxicity to aquatic organisms up to the limit of water solubility. Furthermore, no inhibitory effects towards microorganisms of activated sludge were recorded.

In addition, due to the ready biodegradability (67% in 28 d, OECD 301 C) and the high adsorption potential (> 5.0, KOCWIN v2.00) of the target substance, the substance is expected to be eliminated from sewage treatment plants to a high extent. Release to the aquatic environment and subsequent exposure of sediment is therefore very unlikely. Furthermore, in the unlikely event of absorption by aquatic organisms, the substance (being a long-chain aliphatic ester) is expected to be rapidly metabolized via enzymatic hydrolysis into its corresponding fatty acid and fatty alcohol components, which, in turn are known to metabolize well in aquatic organisms as well. In the unexpected event where absorption of the substance by aquatic organisms should occur, it is therefore expected to be rapidly metabolized via enzymatic hydrolysis into its corresponding fatty acids and fatty alcohols, which are known from literature to metabolize well in aquatic organisms. Against this background, the overall potential for chronic exposure and for bioaccumulation in aquatic organisms is judged to be very low.

Therefore, it can be concluded that the target substance lauryl laurate (CAS 13945-76-1) presumably does not cause short-term or long-term toxicity to aquatic organisms up to the limit of water solubility and is not expected to affect the degradation process in commercial sewage treatment plants.