Registration Dossier

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Description of key information

It is considered likely that the substance sodium permanganate may cause similar neurotoxicity to other manganese compounds and this is therefore considered in the DNEL derivation.

Key value for chemical safety assessment

Additional information

There is a substantial literature on the effects of manganese on the human nervous system. High exposures can result in severe neurotoxic signs and symptoms, some of which resembie those of idiopathic Parkinson's disease. This syndrome, which may also include psychiatric manifestations, has become known as 'manganism'. M anganese mainly induces damage to the globus pallidus (particularly the internal segment) with changes to the substantia nigra pars compacta and the absence of Lewy bodies. This contrasts with what is seen in Parkinson's disease, in which there is preferential degeneration of dopamine neurons in the substantia nigra pars compacta coupled with Lewy bodies and preservation of the pallidum. Overt manganism has been described in a number of early papers that reported studies on neurological signs and symptoms in workers with relatively high and long-term occupational exposures. More recently, several studies on lower occupational exposures to manganese have reported less severe, subtle, non-clinical neurofunctional effects. These subtle effects usually consist of deterioration in motor function and co-ordination and, as such, may constitute manganese-induced changes in the same area of the brain as manganism, that is the basal ganglia and, in particular, the globus pallidus.

A review of the neurological effects of inorganic manganese is beyond the scope of this UCLID 5 dossier. Nevertheless, it is considered likely that the substance sodium permanganate may cause similar neurotoxicity to other manganese compounds and this is therefore considered in the DNEL derivation.

Justification for classification or non-classification