Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Endpoint summary

Administrative data

Description of key information

Additional information

Measured ecotoxicity data is only available for 6.1.3 Short term toxicity to aquatic invertebrates. This proprietary study reports a 48hr EC50 for Daphnia magna of 7.3mg/l.

In accordance with column 2 of REACH Annex VII and VIII, the acute toxicity tests do not need to be conducted if there are mitigating factors indicating that aquatic toxicity is unlikely to occur. Buta-1,2-diene is a gas at standard temperature and pressure and is expected to partition primarily to air, therefore aquatic toxicity tests may not be relevant. In addition, it is technically difficult to maintain aqueous concentrations of gases for toxicity testing. Therefore, in the absence of measured data the ECOSAR model has been used to calculate the likely toxicity of buta-1,2-diene to aquatic organisms. The ECOSAR model is a reliable and appropriate QSAR model to apply to buta-1,2-diene as it is based on a related chemical dataset that calculates the toxicity of neutral organic hydrocarbons whose mode of action is non-polar narcosis. The endpoint calculated here is therefore a reasonable estimate of its baseline toxicity.

It must be noted that although the calculated ecotoxicity data are below the measured water solubility the water solubility test was not done under representative natural environmental conditions. The high volatility of this substance will significantly reduce observed concentrations in water.