2-methoxyethyl acrylate

Endpoint summary

Additional information

One study on the acute toxicity to aquatic invertebrates is available for 2-methoxyethyl acrylate (CAS 3121-61-7), resulting in a 48h-EC50 of 6.7 mg/L (nominal). For other endpoints, read-across was conducted to other structurally analogue substances.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "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. In particular, information shall be generated whenever possible by means other than vertebrate animal tests, through the use of alternative methods, for example, in vitro methods or qualitative or quantitative structure-activity relationship models or from information from structurally related substances (grouping or read-across).” According to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006, physico-chemical, toxicological, ecotoxicological and environmental fate properties may be predicted from data for reference substance(s) by interpolation to other substances on the basis of structural similarity.

The substances methyl acrylate (CAS 96-33-3) and ethyl acrylate (CAS 140-88-5) within the analogue approach of 2-methoxyethyl acrylate (CAS 3121-61-7) meet the requirements of these general rules and are selected as source substances for assessment of ecotoxicological properties. Similarity is justified on basis of the representative molecular structure, physico-chemical properties and environmental as well as ecotoxicological profiles. There is convincing evidence that these chemicals lie in the overall common profile identified within this analogue approach.

 

The key points that the members share are:

· Similar structural features: The target and source substances are characterized as short chain alkyl esters of acrylic acid. They contain a common basic functional group, acrylate ester (CH₂=CH-COOR), where the not common functional group (R) of the source substances are alkyl homologues (methyl- and ethyl-), and the equivalent of the target substance is a methoxylated ethyl group. Acrylates are reaction products of acrylic acid and the corresponding alcohol with addition of catalysts.

· Similar physico-chemical properties: The target and source substances are liquid at room temperature (melting points ranging from -76.5 to -45 °C) and volatile as characterised by their high vapour pressures (4000 and 9000 Pa for ethyl and methyl acrylate, respectively, and 281 Pa for 2-methoxyethyl acrylate). All substances exhibit high water solubilities ranging from 20 to 144 g/L. The log Kow values for the target and source substances are low and range from 0.74 to 1.20.

· Similar environmental fate and ecotoxicity profile: The target and source substances show a constant pattern in their environmental profiles that comprises rapid photodegradation and ready biodegradability. Hydrolysis is expected to be very slow. Besides, they all can be assumed to have a low bioaccumulation potential and low adsorption potential to soils and sediments due to their low log Kow and Koc values. Regarding ecotoxicity, effect values for acute aquatic toxicity were observed in the range of 2.6 to 7.9 mg/L for fish, aquatic invertebrates and algae. Chronic aquatic toxicity data are available only for the source substance ethyl acrylate with a NOEC of 0.19 mg/L for aquatic invertebrates. These data demonstrate that functional groups not common to source and target substances do not affect the anticipated toxicity.

Data on short-term aquatic toxicity are available for fish, aquatic invertebrates and algae from a structurally analogue substance, ethyl acrylate (CAS 140-88-5), which was considered suitable for read-across.

For fish, a 96h-LC50 of 4.6 mg/L was reported, for Daphnia, a 48h-EC50 of 7.9 mg/L was obtained and for algae, a 72h-EC50 of 4.5 mg/L was shown (all concentrations related to mean measured). Besides as above-mentioned, one study on acute toxicity to aquatic invertebrates is available for 2-methoxyethyl acrylate (CAS 3121-61-7), resulting in a 48h-EC50 of 6.7 mg/L (nominal). Hence it can be concluded that the effect concentrations for short-term aquatic toxicity are in the same range across the trophic levels, and also in the same range for the source and target substance regarding read-across.
For long-term aquatic toxicity, data on aquatic invertebrates are available from a structurally analogue substance, ethyl acrylate (CAS 140-88-5), which was considered suitable for read-across. From this study, a 21d-NOEC of 0.19 mg/L (mean measured) was derived for Daphnia. Chronic data for fish and algae are not available, but can assumed to lie on a comparable level as also the acute toxicity values were shown to be in the same range.

For aquatic microorganisms, a 72h-EC10 of > 100 mg/L was obtained for activated sludge. Due to structural and property similarities with the tested analogue substances, it can be concluded that the above results also apply to 2-methoxyethyl acrylate (CAS 3121-61-7). For more details see analogue justification in Chapter 13 of the Technical Dossier.