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No data is available for the UVCB substance itself so the information required for these end points is obtained by read across and use of data from the main components. A full and detailed justification for a category approach for meeting the individual data requirements for glycol ethers to support read across is included as an attachment in chapter 13 to this dossier. For these specific end points, the category document shows a clear trend of decreasing toxicity to aquatic species with reducing length of the alkyl chain length of the alcohol used to produce the glycol ether and increasing number of EO units in the chain. Interpolation from the results of other similar glycol ethers , particularly those with similar partition coefficients, can be considered a valid approach to meeting the data requirements of this substance.

A number of acute toxicity studies are available in fish, invertebrates and microorganisms for the major component 2-(2-(2-ethoxyyethoxy)ethoxy)ethanol which is practically non-toxic to these organisms. The LD50 was always in excess of the maximum tested dose. A reliable QSAR along with the information from the category document, support the conclusion that that the other major component, 3,6,9,12-tetraoxatetradecan-1-ol, will be less toxic than 2-(2-(2-ethoxyethoxy)ethoxy)ethanol so it seems an acceptable conservative approach to use data from 2-(2-(2-ethoxyethoxy)ethoxy)ethanol in place of absent data for the UVCB substance itself for these three end points.

For algal toxicity, there is no measured data for any components of the UVCB substance. There is however measured data for two substances either side of it in the homologous series of these triethylene glycol ethers. 2-(2-(2 -methoxyyethoxy)ethoxy)ethanol (TEGME) has a measured 72hr EC0 of >500mg/l (maximum tested dose) whereas 2-(2-(2 -butoxyyethoxy)ethoxy)ethanol has a measured 72 hr EC10 of 613mg/l.. Since the logKow is the primary determinant of the likely toxicity, the value for 2-(2-(2 -methoxyyethoxy)ethoxy)ethanol (TEGME) is likely to be closest to actual unknown value for the two main components of this UVCB substance, 2-(2-(2-ethoxyethoxy)ethoxy)ethanol and 3,6,9,12-tetraoxatetradecan-1-ol. As a conservative approach, the key value for the EC50 (rounded to 2 significant figures) representative of the UVCB substance is taken from the as the lower of the two QSAR predicted EC50 values for these two component substances.

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