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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

Data for surrogate substance:
Pseudokirchneriella subcapitata, 72hr, EC50 (biomass) 520mg/l (protocol: ISO) EC10=300mg/l
Scenedesmus subspicatus: 72hr EC10>500mg/l (growth rate & biomass)

QSAR predictions:

2 -(2 -butoxyethoxy)ethyl acetate: EC50 (96hr)=75mg/L

2 -butoxyethyl acetate: EC50 (96hr)=38mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
520 mg/L
EC10 or NOEC for freshwater algae:
300 mg/L

Additional information

There is no toxicity data for algae available for 2 -(2 -butoxyethoxy)ethyl acetate. However, there is data available for a read across substance 2 -butoxyethyl acetate which is sufficient to meet the requirements of the end point. A read across justification is attached as a separate document to chapter 13 of the IUCLID. This concludes that the read across is both justified and likely to be conservative and over-predict the toxicity of 2 -butoxyethyl acetate. Two experimentally derived results for the latter are available, both showing relatively low toxicity to the species. The study used as the key study shows the lower of the two results and is to a modern protocol. It is deemed reliable, although the available publication is not particularly detailed. The data is sufficient to judge with confidence that the substance is of low toxicity to algae. The data is also sufficient to provide evidence that this trophic level does not provide the critical NOEC for use in deriving the PNEC for the aquatic compartment.

Read across is also supported by a valid QSAR which predicts that the acute toxicity to algae for 2 -(2 -butoxyethoxy)ethyl acetate will be 75mg/L (96hr EC50) and that the chronic toxicity will be 15mg/L. For comparison, the closely related substance 2 -butoxyethyl acetate is predicted by the same QSAR to have a 96hr EC50 of 38mg/L and a chronic ChV of 8mg/L. This confirms that using real data from the latter will be conservative in estimating the toxicity of the former target substance to algae.