Gases (petroleum), light steam-cracked, butadiene conc.

Endpoint summary

Description of key information

Constituents of Category D are all gases and as such the evaluation carried out for it is tailored to the physical state of the constituents and the composition. Constituents within the Category D are not classified for the environment or human health with the exception of 1,3-butadiene which has a human health classification. Therefore, it was prioritised for inclusion in the ecotoxicological evaluation.

Environmental exposure was not performed for the Category D as the representative constituents do not have any environmental classifications. For Category D 1,3-butadiene was modelled in the environment but only to assess man via the environment exposure and not for any other environmental endpoint as butadiene does not have an environmental classification. The exposure working group agreed this approach as the most sensible approach to implement for Category D.

As per ECHA UVBC guidance, representative constituents were those with concentration greater or equal to 10% (v/v) and/or are CMRs.

The members of this category are gases at standard temperature and pressure and will predominantly partition to the atmosphere, which will limit their aquatic toxicity. Consequently, conducting aquatic ecotoxicity tests on these streams is technically difficult and based on exposure estimates the test is not relevant.

 

Due to the difficulty associated with conducting aquatic toxicity tests on these stream, experimental data are not available for the members of this category. In the absence of measured data, the use of QSAR to predict the ecotoxicity of representative constituents of these streams is an appropriate technique for aquatic toxicity and it is more appropriate to consider the toxicity of representative constituents of these streams.

 

ECOSAR v.1.11 (Epi Suite 4.1) has been used as key QSAR. The representative constituents of the category studied and used as supporting read-across are But-1-en-3-yne (CAS 689-97-4), But-1-ene (CAS 106-98-9), But-2-ene, cis- (CAS 590-18-1), But-2-ene, trans- (CAS 624-64-6), Buta-1,2-diene (CAS 590-19-2), Buta-1,3-diene (CAS 106-99-0), Butane (CAS 106-97-8), Prop-1-ene, 2-methyl- (CAS 115-11-7), and Propane, 2-methyl- (CAS 75-28-5).

 

The acute toxicity of the representative constituents of the category were predicted to range from 12.405 mg/L to 148.62 mg/L, whereas the chronic toxicity of representative constituents was predicted to range from 1.563 mg/L to 13.605 mg/L for the different aquatic taxonomic groups. These values indicate that the toxicity criteria stipulated in Annex XIII are unlikely to be met. Therefore, this Category is considered to be not T on the basis of the screening criterion.

 

CAS Numbers 92045-23-3 and 95465-89-7 are both listed in Annex VI to CLP Annex I but are not classified for environmental hazards. Additionally constituents Butane, 2 -Methylpropane, Butene and 2 -Methylpropene are listed in Annex VI to CLP but are not classified for environmental hazards. This Category would not be classified for environmental hazards.