Slags, ilmenite electrothermal smelting

Endpoint summary

Additional information

UGI (Upgraded Ilmenite) consists primarily of a titanate phase (solid solution) most of which is Ti in an oxidised form. Upon uptake into the body, a low rate of dissolution in the respiratory or gastrointestinal tracts is assumed, based on the experimental verified inertness of the material in artificial physiological media. Any material being released from UGI under physiological conditions will thus be in the form of ionic Ti, which is similarly the case for titanium dioxide: more specifically, the results from in vitro bioaccessibility testing in such fluids demonstrate a similar dissolution pattern of UGI and titanium dioxide (see summary reported under point 7.1.1 basic toxicokinetics), thus read-across from genotoxicity data on titanium dioxide is considered feasible without any restrictions.

In vitro genetic toxicity tests

It is concluded that titanium dioxide did not induce micronuclei in cultured human peripheral blood lymphocytes following treatments in the absence and presence of an Aroclor induced rat liver metabolic activation system (S-9). Concentrations were tested and analysed up to and in excess of the solubility limit in culture medium.

It is concluded that titanium dioxide did not induce mutation at the tk locus of L5178Y mouse lymphoma cells when tested under the conditions employed in this study up to 500µg/mL. These conditions included treatments up to precipitating concentrations in two independent experiments, in the absence and presence of a rat liver metabolic activation system (S-9). Furthermore titanium dioxide did not induce chromosome aberrations in chinese hamster ovary cells (CHO) when tested under the conditions employed in this study up to 2500µg/mL. These conditions included treatments up to precipitating concentrations in two independent experiments, in the absence and presence of a rat liver metabolic activation system (S-9).

In vivo genetic toxicity tests

It has been shown that titanium dioxide does not induce micronuclei or chromosome aberration in the bone marrow of male B6C3F1 mice following a single intraperitoneal injection of 1500 and 2500 mg titanium dioxide /kg bw respectively.

It can therefore be concluded thattitanium dioxidedoes not cause genetic toxicity in vitro and in vivo.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Genetic toxicity, in vivo:

The reference Shelby, M.D. (1995) is considered as the key study for in vivo genetic toxicity and will be used for classification. The overall results are as follows:

Titanium dioxide did not show a significant or dose-dependent increase in chromosome aberrations in the bone marrow of male mice via i.p. injection up to the maximum dose of 2500mg/kg bw 17 and 36 hours after dosing.

Titanium dioxide did not show a significant or dose-dependent increase in micronucleated cells in the bone marrow of male mice via i.p. injection up to the maximum dose of 1500mg/kg bw 24 hours after dosing.

 

Genetic toxicity, in vitro:

None of the in vitro genotoxicity studies rated as reliable showed any effect in bacterial reverse mutation assays, in mammalian cell gene mutation tests (TK assay) or in mammalian cell chromosome aberration tests, thus supporting the negative findings in the in vivo tests as cited above. The classification criteria acc. to regulation (EC) 1272/2008 as germ cell mutagen are also not met.