Fatty acids, C16-18, lithium salts

Endpoint summary

Description of key information

It is considered from the results that all the substances in the category of lithium salts of C14-C22 monocarboxylic acids exhibit a similar lack of acute oral and dermal toxicity potential across the entire category. There is no evidence of a relevant intrinsic acute oral or dermal toxicity requiring classification or substance specific RMMs. An estimate of the inhalative dust/mist toxicity by route-to-route extrapolation result in an ATE well above the cut-off values for classification for acute inhalation toxicity hazard.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High. Reliable, adequate and relevant data available to fulfill the tonnage-driven data requirements of REACH. Tested substance is representative of the lithium salts of C14-C22 fatty acids category and can be read across to other category members.

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

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High. Reliable, adequate and relevant data available to fulfill the tonnage-driven data requirements of REACH. Tested substance is representative of the lithium salts of C14-C22 fatty acids category and can be read across to other category members.

Additional information

The substances in the category are considered to be similar on the basis that they have common structures of a lithium ion varying only by the length of the fatty acid chain and the presence of unsaturated and/or hydroxyl functional groups. As a result, it is expected that the substances will have similar, predictable properties. Due to the close structural similarity and the narrow range of carbon chain numbers covered in this category, the acute toxicity potential is expected to be similar across the category.

Although fatty acids C18 (unsaturated) lithium salts is not in the list of substances being registered, this substance falls within the definition of the lithium salts of fatty acids C14-C22 category (see Category Justification Document) by virtue of its chemical structure and therefore read across from data on fatty acids C18 (unsaturated) lithium salts to other members of the category is considered to be justified.

A number of key acute oral and dermal toxicity studies in rats have been conducted on lithium salts of myristic (C14), 12-hydroxystearic (C18 hydroxylated), stearic (C18), C18 unsaturated, and behenic (C22) monocarboxylic acids. The results from these studies showed no evidence of acute toxicity up to the highest doses tested (2000 mg/kg or greater). In addition, several supporting acute toxicity studies on lithium 12 -hydroxystearate in rats and rabbits have also been considered which, on a weight of evidence basis, provide data which supports the lack of acute toxicity of the lithium salts of C14 -C22 monocarboxylic acids. Several of the latter studies were conducted on the substance contained within a grease base at lower concentrations. However, no conflicting results were seen, and the data also supports the low acute toxicity of the category members.

It is considered from the results that all the substances in the category of lithium salts of C14-C22 monocarboxylic acids exhibit a similar, lack of acute oral and dermal toxicity potential across the entire category. There is no evidence of a relevant intrinsic acute oral or dermal toxicity requiring classification or substance specific RMMs. An estimate of the inhalation dust/mist toxicity by route-to-route extrapolation using conservative standard default values results in an ATE of 10.4 mg/L/4h minimum. This value is well above the cut values for classification for acute inhalation toxicity hazard.

Justification for selection of acute toxicity – oral endpoint
The data are representative of the lithium salts of C14 - C22 fatty acid substances and can be read across to other category members.

Justification for selection of acute toxicity – dermal endpoint
The data are representative of the lithium salts of C14 - C22 fatty acid substances and can be read across to other category members.

Justification for classification or non-classification

The oral and dermal LD50 values are greater than 2000 mg/kg bw. An estimate of the inhalation dust/mist toxicity by route-to-route extrapolation according to ECHA CLP TGD 3.1.3.3.4i results in an ATE well above the cut-off values for classification for acute inhalation toxicity hazard.