Distillates (petroleum), cracked, ethylene manuf. by-product, C9-10 fraction

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In vitro and in vivo genotoxicity data are available for 2 streams within this category - CAS 68477-54-3 (Low Dicyclopentadiene Resin Oil) and CAS 68478-10-4 (Dicyclopentadiene/Codimer Concentrate). In vitro data are available 5 streams: CAS 64742-94-5 (Solvent naphtha (petroleum), heavy arom.), CAS 101316 -62 -5 (Extract residues (coal), light oil alk., acid ext., indene fraction), CAS 68516-20-1 (Naphtha (petroleum), steam-cracked middle arom.), CAS 68526-56-7 (Alkenes, C9-11, C10-rich), and CAS 65996-79-4 (Solvent naphtha (coal)). The stream studies show negative results. However, there are substantial data on the genotoxicity of some of the specific constituents present in some streams. Streams that contain ≥ 0.1% benzene are considered to be mutagenic and will require classification for this end-point.

Additional information

According to the testing proposal generated by the LOA REACH Consortium, all UVCB streams in Category L will be tested for genetic toxicity endpoints. Full details are available in the testing proposal included in Section 13.

In vitro and in vivo genotoxicity data are available for two specific streams identified for this category:

In vitro gene mutation in bacteria and in vivo micronucleus:

CAS 68477-54-3 (Low Dicyclopentadiene Resin Oil): No positive mutagenic response was observed in a bacterial reverse mutation test using Salmonella typhimurium tester strains TA98, TA100, TA1535 and TA1537 and Escherichia coli tester strain WP2 uvrA in the presence and absence or Aroclor-induced rat liver S9 (ACC, 2004m). Negative results were also seen in vivo. Not statistically significant increase in micronucleated polychromatic erythrocytes was seen in male or female mouse bone marrow when evaluated after two administrations, approximately 24 hours apart. The highest dose administrated on the study was 1750 mg/Kg (ACC, 2004o).

CAS 68478-10-4 (Dicyclopentadiene/Codimer Concentrate): This stream was shown to have no mutagenic activity in a bacterial reverse mutation test using Salmonella typhimurium tester strains TA98, TA100, TA1535 and TA1537 and Escherichia coli tester strain WP2 uvrA in the presence and absence or Aroclor-induced rat liver S9 (ACC, 2004l). No evidence of genotoxicity was seen in an in vivo mouse micronucleus test dosed at 1750 mg/Kg (2 doses at 24 hour interval) (ACC, 2004n).

CAS 64742-94-5 (Solvent naphtha (petroleum), heavy arom.): This stream was shown to have no mutagenic activity in a bacterial reverse mutation test using Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and one tryptophan-requiring strain of Escherichia coli (WP2 uvrA) when tested under the conditions of this study. These conditions included treatments at concentrations up to 5000 µg/plate (the maximum recommended concentration according to current regulatory guidelines and a precipitating concentration), in the absence and in the presence of a rat liver metabolic activation system (S-9) (Covance 2020).

In vitro gene mutation in bacteria:

CAS 101316-62-5(Extract residues (coal), light oil alk., acid ext., indene fraction): This stream was shown to have no mutagenic activity in a bacterial reverse mutation test using Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and one tryptophan-requiring strain of Escherichia coli (WP2 uvrA) when tested under the conditions of this study. These conditions included treatments at concentrations up to 5000 µg/plate (the maximum recommended concentration according to current regulatory guidelines and a precipitating concentration), in the absence and in the presence of a rat liver metabolic activation system (S-9) (Covance 2020).

CAS 68516-20-1 (Naphtha (petroleum), steam-cracked middle arom.): This stream was shown to have no mutagenic activity in a bacterial reverse mutation test using Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and one tryptophan-requiring strain of Escherichia coli (WP2 uvrA) when tested under the conditions of this study. These conditions included treatments at concentrations up to 5000 µg/plate (the maximum recommended concentration according to current regulatory guidelines and a precipitating concentration), in the absence and in the presence of a rat liver metabolic activation system (S-9) (Covance 2020).

CAS 68526-56-7 (Alkenes, C9-11, C10-rich): This stream was shown to have no mutagenic activity in a bacterial reverse mutation test using Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and one tryptophan-requiring strain of Escherichia coli (WP2 uvrA) when tested under the conditions of this study. These conditions included treatments at concentrations up to 5000 µg/plate (the maximum recommended concentration according to current regulatory guidelines and a precipitating concentration), in the absence and in the presence of a rat liver metabolic activation system (S-9) (Covance 2020).

CAS 65996-79-4 (Solvent naphtha (coal)): This stream was shown to have no mutagenic activity in a bacterial reverse mutation test using Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and one tryptophan-requiring strain of Escherichia coli (WP2 uvrA) when tested under the conditions of this study. These conditions included treatments at concentrations up to 5000 µg/plate (the maximum recommended concentration according to current regulatory guidelines and a precipitating concentration), in the absence and in the presence of a rat liver metabolic activation system (S-9) (Covance 2020).

In vitro micronucleus:

CAS 64742-94-5 (Solvent naphtha (petroleum), heavy arom.): This stream did not induce micronuclei in cultured human peripheral blood lymphocytes when tested up to toxic concentrations for 3+21 hours in the absence and presence of a rat liver metabolic activation system (S-9) and for 24+24 hours in the absence of S-9 (Covance 2020).

CAS 101316-62-5 (Extract residues (coal), light oil alk., acid ext., indene fraction): This stream did not induce micronuclei in cultured human peripheral blood lymphocytes when tested up to toxic concentrations for 3+21 hours in the absence and presence of a rat liver metabolic activation system (S-9) and for 24+24 hours in the absence of S-9 (Covance 2020).

CAS 68526-56 -7 (Alkenes, C9-11, C10-rich): This stream did not induce micronuclei in cultured human peripheral blood lymphocytes when tested up to toxic concentrations for 3+21 hours in the absence and presence of a rat liver metabolic activation system (S-9) and for 24+24 hours in the absence of S-9 (Covance 2020).

CAS 65996-79-4 (Solvent naphtha (coal)): This stream did not induce micronuclei in cultured human peripheral blood lymphocytes when tested up to toxic concentrations for 3+21 hours in the absence and presence of a rat liver metabolic activation system (S-9) and for 24+24 hours in the absence of S-9 (Covance 2020).

In vitro gene mutation:

CAS 68477-54-3 (Distillates (petroleum), steam-cracked, C8‑12 fraction): This stream was shown to be non-mutagenic at the hprt locus in mouse lymphoma L5178Y cells when tested up to concentrations at, or very close to, the toxicity limit for 3 hours in the absence and presence of a rat liver metabolic activation system (S-9) (Covance 2020).

Specific constituents which have been identified as present in some streams and shown to be mutagenic in vivo:

Benzene (Classification: GHS/CLP - Category 1B, H340): Benzene has been extensively examined for mutagenicity both in vitro and in vivo in a range of recognised core assay types. It has shown mixed results for mutagenicity in vitro although in mammalian cells there is overall evidence for potential mutagenic activity (EU, 2008b). Benzene has been shown to be mutagenic in vivo in both somatic cells and germ cells (Ciranni et al, 1991).

Further studies: Genotoxicity studies to address endpoints are currently ongoing to generate data for gene mutation in mammalian cells: OECD 487 - in vitro micronucleus, as well as OECD 476 - in vitro gene mutation. These data will replace data derived from the UVCB constituents as they become available.

References

EU (2008b). European Union Risk Assessment Report for Benzene. EC Joint Research Centre. http: //ecb. jrc. ec. europa. eu/documents/Existing-chemicals/RISK_ASSESSMENT/REPORT/benzenereport063. pdf.

Justification for classification or non-classification

Available data for streams in this category and specific constituents present within some streams indicate the Resin Oils and Cyclic Dienes that contain <0.1% benzene are considered not to be mutagenic and no classification will be required under Reg (EC) 1272/2008.

It is proposed that Resin Oils and Cyclic Dienes streams containing ≥0.1% benzene are classified as Cat 1B, H340 under Reg (EC) 1272/2008 “May cause genetic defects”. Resin Oils and Cyclic Dienes streams that contain <0.1% benzene.