Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Measured data are not available for the aquatic toxicity endpoints. 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. Acetylene 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.

In the absence of measured data the ECOSAR model ECOWIN v1.00 (Nabholz and Mayo-Bean 2009) has been used to calculate the likely toxicity of acetylene to aquatic organisms. The ECOSAR model is a reliable and appropriate QSAR model to apply to Acetylene 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.

The ECOSAR model estimates a 96-hour LC50 for fresh water fish of 545 mg/L, a 48-hour EC50 of 242 mg/L for fresh water invertebrates and a 96-hour EC50 of 57 mg/L for fresh water algae. These values indicate that the toxicity criteria stipulated in Annex XIII would not be met. Therefore, acetylene is not considered to be T on the basis of the screening criterion and there is evidence that the criterion stipulated in Annex XIII is also not met.