Residues (petroleum), vacuum distn. residue hydrogenation

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

This information was not available.

Additional information

No reproductive study on bitumen has been performed. However, based on the results from repeated-dose toxicity studies, dermal exposure to bitumen at doses up to 2000 mg/kg did not show any treatment related effects on reproductive organ weights and histopathology.

Table 1. Summaries of data on reproductive organs from subchronic studies with bitumen          (Robust study summaries are provided in Section 7.5 Repeated Dose Toxicity)
Test Material	Route, Species, Doses, Exposure Regimen	Endpoints	Results	Reference
Vacuum residuum (API 81-13)	Dermal. Rabbit. 0, 200, 1000, 2000 mg/kg, applied on a gauze pad and wrapped for 6 hr, 3 d/wk for 4 wk	Weights of testes and ovaries. Histopathology of seminal vesicles, testes, epididymides, prostate, ovaries, uterus, and vagina	No treatment-related effect on reproductive organs noted.	API, 1983a
Vacuum residuum (API 81-14)	Dermal. Rabbit. 0, 200, 1000, 2000 mg/kg, applied on a gauze pad and wrapped for 6 hr, 3 d/wk for 4 wk	Weights of testes and ovaries. Histopathology of seminal vesicles, testes, epididymides, prostate, ovaries, uterus, and vagina	No treatment-related effect on reproductive organs noted.	API, 1983b

The need for a 2-generation reproductive toxicity study with bitumen is considered questionable based on the following observations.

1) No effects were seen in weights of testes or ovaries or in the histopathology of seminal vesicles, testes, epididymides, prostate, ovaries, uterus, or vagina in two 4-week dermal studies in rabbits with bitumen at doses up to 2000 mg/kg.

2) Additional supporting evidence comes from separate dermal screening-level fertility studies of syntower bottoms in males and females. The NOAEL was ≥ 250 mg/kg/day. Although not in the bitumen category, this test substance contains significantly higher levels of PACs than bitumen and is one of the more toxic petroleum streams.

 

Nonetheless, there is a clear data gap with respect to the REACH Annex X testing requirements for a two-generation reproductive toxicity study. Therefore a 2-generation reproductive study (OECD guideline 416) is proposed.

 

Short description of key information:
No reproductive study on bitumen has been performed. However, some indication of the likely effect of a test substance on reproductive organs can be gained from the results of repeated-dose toxicity studies where the weights and histopathology of reproductive organs were not affected following dermal exposure to bitumen at doses up to 2000 mg/kg.

Effects on developmental toxicity

Description of key information

No developmental inhalation study on bitumen has been performed. 

Additional information

No developmental inhalation study on bitumen has been performed. There is a data gap with respect to the REACH Annex X (8.7.2) testing requirements for a developmental toxicity study with bitumen. The proposed study would be performed in accord with OECD Guideline 414(Prenatal Developmental Toxicity Study).

Justification for classification or non-classification

No comprehensive guideline developmental or 2-generation reproductive toxicity studies were available for bitumen. A test proposal is included, but currently available data do not raise concern with regard to classification of bitumen as toxic for reproduction or development under CLP Regulation, (EC)1272/2008.