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Description of key information

No acute toxicity studies with zinc bis(2-ethylhexanoate) are available. In the assessment of toxicity of zinc bis(2-ethylhexanoate), read-across to the assessment entities zinc and 2-ethylhexanoic acid is applied since the ions of zinc bis(2-ethylhexanoate) determine its toxicity in biological compartments.

Signs of acute oral or acute dermal toxicity are not expected for zinc bis(2-ethylhexanoate), since its two moieties zinc and 2-ethylhexanoic 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

Acute toxicity

Existing data on the acute toxicity of the two moieties of bis(2-ethylhexanoate) are detailed below.

 

Zinc

Acute oral toxicity

- With LD50 values consistently exceeding 2,000 mg/kg bw, zinc oxide (LD50 ranges between 5,000 and 15,000mg/kg bw), shows very low level of acute oral toxicity.

Acute inhalation toxicity

- Key study carried out according to OECD guideline no 403 indicating for micro zinc oxide LC50 > 5.7 mg/L/4hrs

Acute dermal toxicity

- There are no available data on which to evaluate acute dermal toxicity for ZnO micromaterial. However, acute dermal toxicity can be considered to be low taking into account the poor percutaneous absorption of zinc oxide or the zinc cation.

2-ethylhexanoate

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 dyspnoea 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 no signs of a toxicity response.  It is concluded that the LD50 is greater than 3640 mg/kg. This result is supported by another study which however was poorly documented.

Acute inhalation toxicity

No mortality in 12 rats (6 m;6f) was observed after 8 h exposure to saturated 2-ethylhexanoic acid vapour in an inhalation hazard test comparable to OECD 403 Annex 1. Maximal achievable concentration in this test system was 0.11 mg/L (Nominal concentration). No acute toxicity has to be expected from 2-ethylhexanoic acid vapour at normal conditions of use. The test demonstrates that vapour inhalation is not the relevant rout for exposure concerning acute toxicity.

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.

Table: Summary of acute toxicity data of zinc bis(2-ethylhexanoate) and the assessment entities.

 

(slightly soluble) zinc substances

2-ethylhexanoic acid

(CAS# 149-57-5)

Zinc bis(2-ethylhexanoate)

(CAS# 136-53-8)

Acute oral toxicity

LD50(rat)>2,000 mg/kg bw

LD50(rat)= 2,043 mg/kg bw

LD50>2,000 mg/kg bw

(calculated)

Acute inhalation toxicity

LD50>5.7mg/L

LD0= 0.11 mg/L air (nominal)

waived, since the substance is used and placed on the market in a non-inhalable form

Acute dermal toxicity

LD50> 2,000 mg/kg bw

LD50> 2,000 mg/kg bw

LD50>2,000 mg/kg bw

(calculated)

 

Zinc bis(2-ethylhexanoate)

Signs of acute oral or acute dermal toxicity are not expected for zinc bis(2-ethylhexanoate), since its two moieties zinc and 2-ethylhexanoic acid have not shown signs of acute oral or acute dermal toxicity. Under the assumption that the two moieties of zinc bis(2-ethylhexanoate) show their toxicological profile individually upon dissolution, the acute oral and dermal (systemic) toxicity of zinc 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 and dermal LD50 for zinc bis(2-ethylhexanoate) is > 2000mg/kg, hence the substance is not to be classified according to regulation (EC) 1272/2008 for acute oral and dermal toxicity as well as for specific target organ toxicity, single exposure (STOT SE). Further testing is not required. For further information on the toxicity of the the two moieties of zinc bis(2-ethylhexanoate), please refer to the relevant assesment entity sections in the IUCLID and CSR.

Justification for classification or non-classification

The calculated oral and dermal LD50 for zinc bis(2-ethylhexanoate) is > 2000 mg/kg, hence the substance is not to be classified according to Regulation (EC) 1272/2008 for acute oral and dermal toxicity as well as for specific target organ toxicity, single exposure (STOT SE).