Manganese neodecanoate

Endpoint summary

Description of key information

No acute toxicity studies with manganese neodecanoate are available, thus the acute toxicity will be addressed with existing data on the dissociation products manganese and neodecanoate.

Signs of acute oral or acute dermal toxicity are not expected for manganese neodecanoate, since the two moieties manganese and neodecanoic acid have not shown signs of acute oral or acute dermal toxicity in experimental testing (both LD50 > 2000mg/kg).

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

Manganese

Acute toxicity: oral

Acute toxicity was determined in male and female Wistar rats. The LD50 -value was 2150 mg/kg, which was the highest dose tested. Three supporting studies were identified which studied the acute oral toxicity in rats and mice. The LD50 -values determined in these studies were > 2000 mg/kg.

 

Acute toxicity: dermal

In the absence of measured data on dermal absorption, current guidance suggests the assignment of either 10 % or 100 % default dermal absorption rates. In contrast, the currently available scientific evidence on dermal absorption of metals yields substantially lower figures, which can be summarised briefly as follows:

Measured dermal absorption values for metals or metal compounds in studies corresponding to the most recent OECD test guidelines are typically 1 % or even less. Therefore, the use of a 10 % default absorption factor is not scientifically supported for metals. This is corroborated by conclusions from previous EU risk assessments (Ni, Cd, Zn) and current metal risk assessments under REACH, which have derived dermal absorption rates of 2 % or far less (but with considerable methodical deviations from existing OECD methods) from liquid media.

However, considering that under industrial circumstances many applications involve handling of dry powders, substances and materials, and since dissolution is a key prerequisite for any percutaneous absorption, a factor 10 lower default absorption factor may be assigned to such “dry” scenarios where handling of the product does not entail use of aqueous or other liquid media. This approach was taken in the in the EU RA on zinc. A reasoning for this is described in detail elsewhere (Cherrie and Robertson, 1995), based on the argument that dermal uptake is dependent on the concentration of the material on the skin surface rather than it’s mass.

The following default dermal absorption factors for metal cations are therefore proposed (reflective of full-shift exposure, i.e. 8 hours):

From exposure to liquid/wet media: 1.0 %

From dry (dust) exposure: 0.1 %

This approach is consistent with the methodology proposed in HERAG guidance for metals (HERAG fact sheet - assessment of occupational dermal exposure and dermal absorption for metals and inorganic metal compounds; EBRC Consulting GmbH / Hannover /Germany; August 2007).

 

 

Neodecanoate

 

Neodecanoic acid has a low potential for toxicity via the oral and dermal routes. 

 

Oral

Male and female rats were gavaged with neodecanoic acid at concentrations of 1, 1.5, 2, 3, or 4 ml/kg to assess acute oral toxicity.  All animals that died during the study did so within 3 days of exposure. Signs of toxicity included lethargy, hypothermia, piloerection, dyspnea, and ataxia. Based on these results, it is concluded that the LD50 is approximately 2.27 ml/kg (2066 mg/kg). 

 

Dermal

In a study that assessed acute dermal toxicity, male and female rats were exposed to 4 ml/kg (3640 mg/kg) neodecanoic acid via an occluded dermal patch for 24 hours. After 24 hours, the patch was removed and clinical observations were made once daily for 9 days. There were no deaths observed in this study and there were no signs of a toxicity response.  It is concluded that the LD50 is greater than 3640 mg/kg. 

 

 

Manganese neodecanoate

Signs of acute oral or acute dermal toxicity are not expected for manganese neodecanoate, since the two moieties manganese and neodecanoic acid have not shown signs of acute oral or acute dermal toxicity in experimental testing (both LD50 > 2000mg/kg). Under the assumption that the moieties of manganese neodecanoate show their toxicological profile individually upon dissolution, the acute oral and dermal (systemic) toxicity of manganese neodecanoate can be calculated using the equation given in regulation (EC) 1272/2008, Annex I, Section 3.1.3.6.1.

A study for acute toxicity via inhalation was not conducted with manganese neodecanoate, since it is produced and placed on the market in a form in which no inhalation hazard is anticipated, thus acute toxic effects are not likely to occur during manufacture and handling of that substance. For further information on the toxicity of the individual moieties, please refer to the relevant sections in the IUCLID and CSR.

 

The calculated oraland dermal LD50 for manganese neodecanoate is > 2000mg/kg, hencethe substance is not to be classified according to regulation (EC) 1272/2008 for acute oral and dermal toxicity.

 

Justification for classification or non-classification

Based on in vivo oral and dermal LD50 data on the moieties, acute toxicity estimates for manganese neodecanoate have been calculated resulting in LD50 values > 2000 mg/kg bw.

According to the criteria of REGULATION (EC) No 1272/2008 and its subsequent adaptions, manganese neodecanoate does not have to be classified and has no obligatory labelling requirement for acute oral or dermal toxicity.