Mill scale (ferrous metal)

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Mill scale is mainly and primarily composed of high-purity iron oxides (on average above 65%, i.e. FeO, Fe2O3, Fe3O4). Besides, other metal oxides and spinels, elements, and trace compounds such as oil residues <1% for all the uses except for batteries and Melting charge for which <3% can be found in the mill scale. More information on the justification of read across can be found in the attached document in the endpoint summarie of section 7.

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Iron oxides

IUPAC Name:

Iron oxides

Results and discussion

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

No studies were identified with a form of iron oxides on reproduction toxicity. However, a study on the effects of iron oxides on reproduction in terms of fertility, as is normally investigated by means of a standard two-generation reproduction toxicity study, is not justified on the following scientific grounds (see also IUCLID Section 7.1).
• Effects on the endpoints measured in a reproduction toxicity study are typically the results of systemic exposure. The endpoints, as they may occur in the gonads (ovaries and testes), the endocrine glands involved in the regulation of reproduction, the placenta, and the uterus, can only be reached by test compounds via the blood, at least when normal, non-invasive exposure routes are applied.
• Human exposure to iron oxides occurs via skin contact with large solid objects, or via the inhalation or ingestion (primary or secondary) of small particles (powders). Based on the physico-chemical properties of iron oxides, any significant systemic exposure upon skin contact can be deemed unlikely. Regarding the oral and inhalation (particles are ingested after clearance from the respiratory tract) route, after ingestion (primary or secondary), the oxides will not be dissolved in the gastric juice due to their physicochemical properties; they will be efficiently eliminated as such via the feces. Therefore, systemic exposure will not occur to any significant extent.
• Intracellular dissolution of the oxide within the alveolar macrophages, after phagocytosis due to the clearance mechanism, proceeds very slowly and its rate is highly dependent on the particle size and specific surface area (see information in IUCLID section 7.1). It is highly unlikely that this will ultimately lead to any significant systemic exposure. For this reason, it is deemed irrelevant for the present endpoint. It can thus be concluded that for a lack of significant systemic exposure, testing of iron oxides for reproduction toxicity is redundant.