Sulphuric acid, compound with graphite

Carcinogenicity

Description of key information

According to Column 2 of Annex X (standard information requirements for substances manufactured or imported in quantities of 1000 tonnes or more) of Regulation (EC) No 1907/2006 a carcinogenicity study may be proposed by the registrant or may be required by the Agency in accordance with Articles 40 or 41 if, inter alia, “…the substance is classified as mutagen category 3 or there is evidence from the repeated dose study(ies) that the substance is able to induce hyperplasia and/or preneoplastic lesions.”
Sulphuric acid, compound with graphite is an inorganic solid, consisting of natural graphite and variable amounts of intercalated sulphuric acid. 
Graphite is a naturally occurring solid substance which is insoluble in water. Due to its physico-chemical properties it is not systemically and biologically available and does not cross biological membranes. In the aquatic compartment it can be considered as an inert substance.
The intercalated sulphuric acid is partially leached out by water and dissociated into the biologically ubiquitous sulphate and hydronium ions. Due to their ionic character, they do not cross biological membranes. Sulphate is a normal biological constituent of the body, a normal biological metabolite and a degradation product of sulphur-containing amino-acids.
The performed Ames-test and the in vitro Mammalian Micronucleus Assay in human lymphocytes clearly show the non-mutagenic potential of sulphuric acid, compound with graphite. Due to its physico-chemical properties sulphuric acid, compound with graphite is neither systemically available nor bioavailable and can therefore not reach or enter critical tissues and organs.
It can be concluded that the substance is highly unlikely to pose a cancerogenic potential. Against this background and in conformity with the ECHA principles of avoiding unnecessary animal testing, it is considered to be unnecessary to perform a carcinogenicity study.

Justification for classification or non-classification

Sulphuric acid, compound with graphite is an inorganic solid, consisting of natural graphite and variable amounts of intercalated sulphuric acid.

The absence of bioavailability and of mutagenic potential was underlined by the negative testing results of the Ames test and the in vitro Mammalian Micronucleus Assay in Human Lymphocytes (see section 7.6.1 of the IUCLID dossier).

In the Ames test no cytotoxic effects of the test item extracts were noted up to the highest concentration in any of the five tester strains used (with and without metabolic activation). As the assays directly measure heritable DNA mutations, which - inter alia - are involved in cancer in humans and experimental systems, conclusions can be derived regarding the potential cancerogenic effects.

Under the experimental conditions of the in vitro Mammalian Micronucleus Assay in Human Lymphocytes no structural and/or numerical chromosomal damage in human lymphocytes has been induced by sulphuric acid, compound with graphite in various concentrations. Therefore the test item was considered to be non-mutagenic with respect to clastogenicity and/or aneugenicity. As the in vitro micronucleus test is the only in vitro test which is able to detect both numerical and chromosomal aberrations, two mechanisms involved in genetic and carcinogenic risk, conclusions can be derived from the testing results regarding potential cancerogenic effects.

 

Against this background, it can be concluded that the substance is highly unlikely to pose a cancerogenic potential, leading to no classification obligation according to the CLP Regulation.