Registration Dossier

Administrative data

Description of key information

No acute toxicity studies with strontium bis(2-ethylhexanoate) are available, thus the acute toxicity will be addressed with existing data on the individual moieties strontium and 2-ethylhexanoic acid.

The calculated oral LD50 for strontium bis (2-ethylhexanoate) is 586.5 mg /kg, hence the substance is classified according to regulation (EC) 1272/2008 as acute toxic via the oral route Category 4 (H302). However, no classification for specific target organ toxicity, single exposure (STOT SE) is required.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50

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

Strontium

Acute oral toxicity

One reliable animal study according to OECD 425 is considered to be reliable without restrictions. The LD50 value was determined to be 1030 mg/kg bw. Based on this, strontium is classified as acute toxic via the oral route (Catergory 4, H302).

The classification criteria according to Regulation (EC) No. 1272/2008 as specific target organ toxicant (STOT) – single exposure, oral are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure and no effects were observed at the guidance value, oral for a Category 1 classification (C≤ 300 mg/kg bw) and at the guidance value, oral for a Category 2 classification (2000 mg/kg bw ≥ C > 300 mg/kg bw). No classification required.

Acute dermal toxicity

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 its 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).

 

2-ethylhexanoic acid

Acute oral toxicity

In an acute oral toxicity study 4 rats/sex/dose were dosed with 90, 722, 1445 or 2890 mg/kg bw. No mortality was observed in the 90, 722 and 1445 mg/kg bw dose groups. The test material caused mortality in rats administered a dose of 2890 mg/kg bw (4/4), and transitory weakness at lower doses in a dose-dependent manner. The LD50 was calculated to 2043 mg/kg bw.

 

In another acute oral toxicity study 5 rats/sex/dose have been administered 0.2, 1.6, 3.2 and 4.0 ml 2-ethylhexanoic acid/ kg bw. No substance related clinical signs nor mortality was observed at 0.2 and 1.6 ml/kg. However, 1/10 animals died. After administration of 3.2 ml/kg and 4 ml/kg apathy dyspnea abdominal position and re crusted eyes and snouts were observed. Mortality in these dose groups was 3/10, 5/10, respectively. LD 50 was estimated to be 4 mL/kg bw, being equivalent to 3640 mg/kg bw (density 0.91 g/ml). This result is supported by another study which however was poorly documented.

 

Acute dermal toxicity

Dermal toxicity of 2-ethylhexanoic acid was tested in an OECD 402 guideline study. Five Wistar rats/sex/dose have been exposed dermally (semi-occlusive to a limit dose of 2000 mg/kg bw 2‑ethylhexanoic acid. No mortality and no clinical symptoms beside eschar formation have been observed. LD50 dermal therefore is > 2000 mg/kg bw.

Strontium 2-ethylhexonate

No acute toxicity studies with strontium bis(2-ethylhexanoate) are available, thus the acute toxicity will be addressed with existing data on the individual moieties strontium and 2-ethylhexanoic acid.

In a relevant and reliable acute oral toxicity study with the assessment entity 2-ethylhexanoic acid no toxicological findings were reported. However, adverse effects observed in an acute oral toxicity study with the moiety strontium were observed. Under the assumption that the moieties of strontium bis(2-ethylhexanoate) show their toxicological profile individually upon dissolution, the acute oral (systemic) toxicity of strontium bis(2-ethylhexanoate) can be calculated using the equation given in regulation (EC) 1272/2008, Annex I, Section 3.1.3.6.1.

The calculated oral LD50 for strontium bis (2-ethylhexanoate) is 586.5 mg /kg, hence the substance is classified according to regulation (EC) 1272/2008 as acute toxic via the oral route Category 4 (H302). However, no classification for specific target organ toxicity, single exposure (STOT SE) is required.

A study for acute toxicity via inhalation was not conducted with strontium bis(2-ethylhexanoate), 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 constituents, please refer to the relevant sections in the IUCLID and CSR.

Signs of acute dermal toxicity are not expected for strontium bis(2-ethylhexanoate), since the two moieties strontium and 2-ethylhexanoic acid have not shown signs of acute dermal toxicity in experimental testing (both LD50 > 2000mg/kg).

Justification for classification or non-classification

The calculated oral LD50 for strontium bis (2-ethylhexanoate) is 586.5 mg /kg, hence the substance is classified according to regulation (EC) 1272/2008 as acute toxic via the oral route Category 4 (H302). However, no classification for specific target organ toxicity, single exposure (STOT SE) is required.