Buta-1,3-diene

Endpoint summary

Additional information

Measured ecotoxicity 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. 1,3 -Butadiene 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 toxicity of 1,3-butadiene has been estimated using two suitable QSARs. The equations used are suitable for non-polar narcotic chemicals. The endpoints calculated here are therefore a reasonable estimate of the baseline toxicity of 1,3-butadiene.

The PBT assessment toxicity screening criteria are that an acute EC50 or LC50 value of <0.1 mg/L is considered to be T, and that an EC50 or LC50 value of <0.01 mg/L indicates that the substance is definitely T. Experimental ecotoxicity data were not available for 1,3-butadiene and therefore, to allow an assessment of the potential toxicity of 1,3-butadiene, (Q)SAR estimates of the acute toxicity were calculated (Verhaar et al, 1995 and Van Leeuwen et al. 1992). The (Q)SAR predictions indicate that 1,3-butadiene is of low toxicity to environmental receptors, with a 96 hour LC50 to fish of 44.8 mg/L, a 48 hour EC50 to invertebrates of 33.3 mg/L and a 72 hour EC50 to algae of 32.6 mg/L. All of the predicted acute LC50 toxicity values are significantly greater than the screening criteria. These values indicate that the environmental toxicity criteria stipulated in Annex XIII are unlikely to be met.