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Ecotoxicological information

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This UVCB substance a mixture of molecules with 3 or more ethylene oxide 'monomer' units with a methoxy terminal function at one end of the molecule and a hydroxyl function group at the other end. The triethylene and tetra ethylene glycol molecules (EO=3 and 4 respectively) are the two main molecules present, with the higher molecular weight members of the family present in diminishing amounts as the number of EO units increases. The category document attached to chapter 12 of the IUCLID dossier shows the trends in how the ecotoxicological properties vary within the E series glycol ethers as a whole and the polyethylene oxide methyl ether series in particular. Toxicity data is available for monoconstituent substance components of this substance that is considered representative of the substance as a whole.

Guideline studies are available for 2 -(2 -(2 -methoxyethoxy)ethoxy)ethanol in two different fish species. Studies show that the substance is effectively non toxic to fish with LC0 values between 5000 -10000mg/l and LC50 values in excess of 10000mg/l. There is no data available on marine fish.

 

Two measured values are available for the acute toxicity in daphnia magna. One study established that the EC0 was in excess of the maximum tested dose of 500mg/l whilst a second study established that the LC50 was in excess of the maximum tested dose of 10000mg/l. A QSAR predicts that the EC50 is much higher at around 70000mg/l. On this basis, it seems reasonable to conclude that the acute toxicity EC50 is likely to be in excess of 10000mg/l and that selecting this value is a conservative choice for the key parameter. There is no data availalble on marine invertebrates.

In a growth inhibition acute toxicity test, the green algae Scenedesmus subspicatus were exposed to concentrations of 2 -(2 -(2 -methoxyethoxy)ethoxy)ethanol at concentrations up to 500mg/l for a period of 72 hours. No growth inhibition was seen, indicating that the substance is practically non-toxic to algae. Whilst only an EC20 is quoted (>500mg/l), it is assumed based on information available in this and other studies that this would be the same as the EC10. This result is supported by information from the ECOSAR QSAR model, which predicts that the 96hr EC50 value for algae would be 14066mg/l and the 96hr NOEC 1810mg/l and from a surrogate substance predicted by the QSAR to be inherently more toxic which shows a NOEC of 1000mg/l . The QSAR result is used as a basis for the EC50 and a conservative key value of 10000mg/l is selected.

In an activated sludge respiration inhibition test, no inhibition was found up to the maximum tested concentration of 2000mg/l. In a Microtox assay using a photobacterium, the IC50 was not reached up to the maximum tested concentration of 5000mg/l. The data indicates that the substance is effectively non toxic to micro-organisms.