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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Sediment toxicity

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Administrative data

Link to relevant study record(s)

Description of key information

The EC50 value as shown below is derived using the partitioning equation, starting with the EC50 value of 2910mg/L, a logKow of 0.81 and the substance type as 'alcohols', to derive and EC50 in units of mg/kgdw sediment.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:
11 400 mg/kg sediment dw

Additional information

In a study designed to generate data to prepare a QSAR model, the acute (48hr) and chronic (96hr) toxicity of 2 -butoxyethanol to the soil/sediment dwelling species C. Elegans was assessed. Acute toxicity was measured in terms of mobility as a proxy for lethality with a derived LC50 values of 2910mg/L. Chronic toxicity was measured in terms of impact on reproduction and growth rate with EC50 values of 1710mg/L and 2750mg/L respectively for these two end points. It is notable that the chronic toxicity 50th percentile for chronic toxicity is <2x lower than that for acute toxicity which suggests that the default factor of 10 normally used in extrapolating from acute to chronic toxicity is excessive for this substance. This should be taken into account when assessing the PNEC for sediment. However, since the PNEC aquatic is derived from a full set of chronic data, it is preferable to derive the PNEC for sediment from this by the equilibrium partitioning method rather than from a single acute toxicity value for a sediment dwelling species. The latter data does support the hypothesis that there is no significant difference in sensitivity between species from different trophic levels.

A waiver for this end point is retained as there is no chronic EC10 or NOEC available.