Neodecanoic acid, zirconium salt

Endpoint summary

Description of key information

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

Signs of acute oral, acute inhalation or acute dermal toxicity are not expected for neodecanoic acid, zirconium salt, since the two moieties zirconium and neodecanoic acid have not shown signs of acute oral, acute inhalation or acute dermal toxicity in experimental testing.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

> 2 067 mg/kg bw

Quality of whole database:

Acute toxicity estimate based on high quality experimental LD50 values for zirconium (>3705 mg Zr/kg bw) and neodecanoic acid (2066 mg/kg bw) and their maximal content in neodecanoic acid, zirconium salt (34% and 81%, respectively).

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

> 2.7 mg/L air

Quality of whole database:

Acute toxicity estimate based on high quality experimental LD50 values for zirconium (>3.2 mg Zr/L) and neodecanoic acid (>3.0 mg/L) and their maximal content in neodecanoic acid, zirconium salt (34% and 81%, respectively).

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 1 557 mg/kg bw

Quality of whole database:

Acute toxicity estimate based on high quality experimental LD50 values for zirconium (>810 mg Zr/kg bw) and neodecanoic acid (>3640 mg/kg bw) and their maximal content in neodecanoic acid, zirconium salt (34% and 81%, respectively).

Additional information

Zirconium

Acute toxicity: oral

One key study was identified (Klimisch 1). Acute toxicity of ZrO2 was determined via the acute class method (OECD Guideline 423 and EU Method B1 tris) in female Sprague-Dawley rats. The LD50 -value was > 5000 mg ZrO2/kg bw, equivalent to >3705 mg Zr/kg bw. Three supporting studies were identified (Klimisch 2) which studied the acute oral toxicity of ZrO2 via a standard acute test in Crj: CD (SD) IGS male and female rats. The LD50 -values determined in these studies were > 2000 mg ZrO2/kg bw.

Acute toxicity: inhalation

One key study (Klimisch 1) was performed by WIL Research Laboratories on request of the MOZO Consortium in 2010. Acute inhalation toxicity was tested according to OPPTS Guideline 870.1300 and OECD Guideline 436. Zirconium dioxide was administered to 1 group of 3 male and 3 female Crl:CD(SD) albino rats via nose-only inhalation exposure as a dust aerosol at a concentration of 4.3 mg ZrO2/L, which was the maximum obtainable mean concentration, for 4 hours. The exposure atmosphere was characterized by a mean mass median aerodynamic diameter (± geometric standard deviation) of 2.0 µm ± 1.75 µm. As no mortality occurred during the study, the LC50 of zirconium dioxide was greater than 4.3 mg/L, equivalent to >3.2 mg Zr/L.

Acute toxicity: dermal

One key study was identified (Klimisch 1). Acute dermal toxicity was determined for zirconium acetate via a standard OECD 402 test in male and female Sprague-Dawley rats. The LD50 -value was > 2000 mg Zr acetate/kg bw, equivalent to >810 mg Zr/kg bw.

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. 

 

Acute toxicity: 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). 

Acute toxicity: inhalation

In acute inhalation study, male Wistar rats and Swiss albino mice (10/sex/species) were exposed the test substance vapour via a whole-body exposure at 3.0 mg/L for 6 hours with a subsequent 14 day observation period. No mortality or significant signs of toxicity were observed during the 6-hour exposure period. No deaths occurred in mice or rats throughout the study and no significant observations were made at necropsy. The LC50 is therefore greater than 3 mg/l (3000 mg/m3).

Acute toxicity: 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. 

 

 

Neodecanoic acid, zirconium salt

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

For further information on the toxicity of the individual moieties, please refer to the relevant sections in the IUCLID and CSR.

Justification for classification or non-classification

Based on in vivo oral, inhalation and dermal LD50 data on the moieties, acute toxicity estimates for neodecanoic acid, zirconium salt have been calculated resulting in a LD50 value > 2000 mg/kg bw for oral exposure and no adverse effect observed up to the largest dose tested for dermal and inhalation exposure.

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