Asphalt, oxidized

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

This information was not available

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

300 mg/m³

Study duration:

subacute

Species:

rat

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

No effects on reproductive organs were observed in repeat dose toxicity studies and there were no effects on reproductive performance in a combined repeat dose toxicity and developmental/reproductive toxicity study (OECD 422) with an emission condensate derived from a severely oxidized asphalt.

1)       No effects were seen in the weights of testes or in the histopathology of testes, epididymis, prostate, seminal vesicles, ovaries, uterus, vagina, or mammary glands in rats exposed by inhalation for 14 weeks to fume condensate from air-rectified (partially oxidized) asphalt at concentrations up to 100 mg/m3.

2)       No effects were seen in the histopathology of testes, epididymis, prostate, seminal vesicles, ovaries, uterus, vagina, or mammary glands in rats exposed by inhalation for 104 weeks to fume condensate from air-rectified (partially oxidized) asphalt at concentrations up to 100 mg/m3.

3)       No effects were seen in(a) weights of testes, epididymides, ovaries, and uterus, (b) histopathology of testes, epididymides, prostate, seminal vesicles, coagulating glands, ovaries, uterus, vagina, fallopian tubes, and mammary glands, (c) staging of seminal epithelium in testes, (d) number and morphology of cauda epididymal sperm, or (e) epididymal sperm motility in rats exposed by inhalation for 28 days to fume condensate from oxidized asphalt at concentrations up to 300 mg/m3.

Nonetheless, there is a clear data gap with respect to the REACH Annex X testing requirements for an extended one-generation reproductive toxicity study. A study proposal is included in the REACH registration dossier - (see Endpoint study record Toxicity to reproduction-Testing proposal-EOGRTS).

Short description of key information:

One key reproductive/developmental screening study (OECD 422) was identified, in which reproductive and developmental effects of oxidised (fully blown) asphalt fume condensate were evaluated in rats. The results do not give any indication that the test item is a reproductive toxin at concentrations up to 300 mg/m³ total hydrocarbon.

Effects on developmental toxicity

Description of key information

One key PNDT study (OECD 414) was identified, in which developmental effects of oxidised asphalt fume condensate were evaluated in rats. The results do not give any indication that the test item is a developmental toxin at concentrations up to 500 mg/m³ (nominal).

Note on choice of exposure route:

A developmental inhalation study on oxidized asphalt has been performed. Oxidized asphalt is a (semi) solid material, therefore it is considered that any potential exposure is solely to the fumes that may arise during occupational handling of the material at elevated temperatures. This study was therefore performed via the inhalation route as this is considered the only relevant route of human exposure, which means that sufficient oxidized asphalt fumes, collected as condensates, were generated before the studies could be conducted.

An additional complexity with applying this approach is that the composition of the condensate is influenced by the occupational conditions, mainly the temperature at which the oxidized asphalt is heated when applied. Thus, Concawe has validated the composition of the condensate collected at the manufacturing site against actual workplace fume samples through a workplace monitoring campaign to ensure that the tested material is representative of real-life exposures.

Full reports of fume collection and validation, as well as workplace monitoring campaigns and fume condensate comparisons, are available from Concawe upon request.

Brief summary of results:

Developmenal NOAEL to rats as determined in OECD 414 inhalation study was 500 mg/m³(maternal NOAEL was 50 mg/m³in the study).

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

500 mg/m³

Study duration:

subacute

Species:

rat

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

There were no developmental effects seen in a PNDT study (OECD 414) with an emission condensate derived from oxidized asphalt.

The developmental NOAEC for the study was 500 mg/m3, (with maternal NOAEC 50 mg/m³).

Justification for classification or non-classification

No comprehensive guideline 2-generation reproductive toxicity studies were available for oxidised asphalt. A PNDT study conducted according to OECD 414 and a screening reproductive/developmental toxicity study evaluating oxidised asphalt fume condensate showed no effects on reproductive or developmental parameters. Although results from the screening study showed no reproductive or developmental effects at the highest dose tested, these data do not strictly meet the REACH Annex X requirement for extended one-generation reproductive studies. A test proposal is included but currently available data do not raise concern with regard to classification of oxidised asphalt as toxic for reproduction or development under EU CLP Regulation (EC No. 1272/2008).