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Key value for chemical safety assessment

Additional information

No evidence of mutagenic activity was seen in five tester strains of Salmonella typhimurium (TA 98, 100, 1535, 1537 and 1538) in four Ames tests (Birtley, 1980; Conz and Fumero, 1988a; Elliott, 1989a; Wiegand, 1989) carried out with C14-17 chlorinated paraffins (40-52% chlorination) in the presence or absence of a rat liver metabolic activation system (S9).

No in vitro gene mutation or cytogenetic studies in mammalian cells on MCCPs are available. Therefore, read-across from SCCPs will be used for the gene mutation data-gap and in vivo data on MCCPs for the cytogenicity data-gap (see below for details).

Negative results were reported in an in vitro gene mutation (HPRT) study (which was performed to modern standards according to the final RAR (EU, 2000)) with a C10-13 chlorinated paraffin (56% chlorination) in Chinese hamster V79 lung cells tested at up to cytotoxic concentrations, with and without S9 (Mϋller, 1987) [Hoechst, 1987]. A similar result would, therefore, be anticipated for MCCPs. It is highly unlikely that the medium-chain analogue (MCCP) would be more active than the shorter-chain material (SCCP). In addition, a well-conducted in vivo germ cell mutagenicity study (dominant lethality) in rats with a C10-12 chlorinated paraffin (58% chlorination) was negative (EU, 2000). No in vivo gene mutation tests for MCCPs are available.

In accordance with column 2 of REACH Annex VIII, an in vitro cytogenicity study in mammalian cells or an in vitro micronucleus study, do not usually need to be conducted if adequate data from an in vivo cytogenicity test are available. In this instance, three reliable in vivo mammalian cytogenicity tests (Spicer, 1983; Conz and Fumero, 1988b; Elliott, 1989b) have been performed with MCCPs. The first, an in vivo bone marrow chromosome aberration test in male rats has been conducted with a C14-17 chlorinated paraffin (52% chlorination). The test material, administered in corn oil for five days at up to 5000 mg/kg bw/day via stomach tube, failed to increase the frequency of chromosome aberrations (including gaps) in the bone marrow of treated animals (Spicer, 1983). In two bone marrow micronucleus tests (Conz and Fumero, 1988b; Elliott, 1989b) no increase in the frequency of micronuclei was reported 24 to 72 hours after male and female mice received a single oral gavage dose of a C14-17 chlorinated paraffin (42 or 45% chlorination) at up to 5000 mg/kg bw (in corn oil). These three in vivo bone marrow studies demonstrate that MCCPs are not clastogenic to this sensitive target tissue. The available toxicokinetic data demonstrate that MCCPs undergo significant absorption following oral administration, with one study (Darnerud and Brandt, 1982), showing distribution to the bone marrow, indicating the reliability of these negative genotoxicity study results.

References (not contained elsewhere in this IUCLID dossier)

Darnerud and Brandt I (1982). Studies on the distribution and metabolism of a14C‑labelled chlorinated alkane in mice. Environ. Pollut.(Series A).27: 45-46 (cited in EU, 2008).


Short description of key information:
C14-17 chlorinated paraffins (40-52% chlorination) consistently showed no evidence of mutagenic potential in four Ames bacterial tests. No in vitro cytogenetic or gene mutation studies in mammalian cells are available for MCCPs. However, for a C10-13 chlorinated paraffin (56% chlorinated) a negative result was obtained in a well-conducted in vitro gene mutation assay tested at up to cytotoxic concentrations in hamster cells; a similar negative result would, therefore, be anticipated for MCCPs. Three in vivo bone marrow studies in rodents demonstrate that C14-17 chlorinated paraffins (42-52% chlorination) are not clastogenic towards this target tissue. Negative results for in vivo genotoxicity tests in somatic and germ cells have been obtained for SCCPs. Overall, the available data on MCCPs and SCCPs indicate that MCCPs do not possess genotoxic activity.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Under EU CLP and DSD regulations, C14-17 chlorinated paraffins would not be classified as mutagenic.